MERU CENTRAL

231/1
PAPER 1
1. What do the branches of biology entail?
(a) Cytology (1mk)
(b) Entomology (1mk)
2. In lichen, algae and fungi live in an association that is beneficial to each organism
a) Name the type of relationship shown by the two organisms that form lichen (1mk)
b) Explain the benefits of the relationship to the organism in association (2mks)
3. Two species in an ecosystem cannot occupy the same niche. Explain (1mk)
4. Use the diagram of an organism shown in the figure below to answer the questions that follow

a) Name the parts labelled A and B

b) State the type of asexual reproduction shown in the diagram, giving reasons (2mks)
5. Name three cells in the leaf which contain chloroplast (3mks)
6. Name the class;
a) Of organism in the phylum arthropoda in which members have four pairs of legs and two body
parts (1mk)
b) Of plants which have floral parts in fours, fives or their multiples (1mk)
7. The diagram below represents a stage during cell division

a) Name the stage of cell division (1mk)

b) Give two reasons for your answer in (a) above (2mks)
c) State the significance of this stage of cell division in living organisms (1mk)
8. In an experiment the concentration of ions in the cell sap of reeds growing in a swamp were
determined. The data below were obtained. study it and answer the questions that follow
Sample Na+ Mg2+ Cl- SO42-
Cell sap 50 11 101 13
Swamp water 1.2 30 10.2 0.67
a) Name the process by which uptake of the following ions by the reeds occurs. (2mks)
Na+
Mg2+
b) What effect would reduced the oxygen supply have on the uptake of (sulphate ions) SO42-
Explain your answer (1mk)
9. The diagram below shows a part of a nephron

a) State two differences in composition of blood in parts P and Q (2mks)

b) State a characteristic feature of blood capillaries in part Q that is not found in other capillaries
(1mk)

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10. A set up was used to investigate a certain process in plants as shown in the diagram below

a) What process was being investigated (1mk)

b) Giving reason, state one precaution that should be taken when setting up the experiment (1mk)
11. Variegated leaves accumulate less food than non-variegated leaves under similar conditions
Explain (2mks)
12. The diagram below show a bone that was obtained from a mammal

a) Identify the bone (1mk)

b) i) Name the type of joint formed at the part marked P
ii) State one characteristic of the joint named in b (i) above (1mk)
13. (a) What is the role of green plants in an ecosystem with respect to energy flow (2mks)
(b) Explain why it is advisable for humans to feed on grains directly rather than first using the
grains to fatten the bulls whose beef is later fed on by humans (3mks)
14. Suggest the possible cause of the following stomach disorders and give one measure that can
control them.
a) Ulcers (2mks)
Cause (1mk)
Control measure (1mk)
b) Constipation
Cause (1mk)
Control measure (1mk)
15. State the function of the following during pregnancy. (3mks)
Amnions
Amniotic fluid
Umbilical cord
16. A portion of nucleic acid is shown below ;

a) Name the nucleic acid to which the portion belongs. Give reason (2mks)
b) Write down the sequence of the bases of a complimentary strand to the one above (1mk)
17. State the function of the following parts of the mammalian ear
a) Eustachian tube (1mk)
b) The utriculus and sacculus (1mk)
18. Distinguish between analogous and homologous structure. For each give an example (4mks)

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19. In an experiment, a shoot of a maize seedling was exposed to light on one side. It was observed
that it grew bending towards the direction of the source of light.
a) Explain how the bending towards light occurs (2mks)
b) State the survival value of the response named in (a) above (1mk)
20. (a)Name the hormone responsible for secondary sexual characteristics (2mks)
i) Males
ii) Females
c) During menstruation there is discharge of blood and debris. What does this indicate?
21. A student set an experiment as shown in the diagram below. The set up was kept at room
temperature for one week.

a) What was the aim of the experiment ? (1mk)

b) State the expected observation at the end of the experiment (1mk)
c) Account for the observation made in set up A (1mk)
22. (a) Name the respiratory surface for gaseous exchange in insects (1mk)
(b) state the adaptations of the site named in (a) above. (2mks)
23. List the changes that take place during inhalation in the breathing cycle of a mammal in the
following; (3mks)
a) Ribcage
b) Diaphragm
c) External intercostal muscles
24. Which organelle would be numerous in the following cells (2mks)
a) Liver cell
b) Palisade cell
25. State 3 advantages of sexual reproduction. (3mks)
26. State the significance of metarmophosis to the life of insects (2mks)
27. Explain the following observations
a) Grass lawns are treated with herbicides containing auxins (1mk)
b) In temperate countries, trees that have begun to bear fruits are sprayed with auxins (1mk)
c) During malting process in beer production, gibberellins are added (1mk)
28. Julie observed eight onion epidermal cells across the field of view of a light microscope. If the
field of view was 4mm in diameter, estimate the average size of cells in
micrometers(1mm=1000 micrometers) (2 mks)

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 MERU CENTRAL
BIOLOGY
231/2
PAPER 2
1. The diagram below shows a set up to investigate a factor necessary for germination

a) Name the factor under investigation (1mk)

b) State the role of pyrogallic acid in the set up
c) Which type of respiration is taking place in the beans. (1mk)
d) Write a word equation for the process named in (c) above (1mk)
e) Explain why plants can only carry out the above respiration process for a short while.
(1mk)
f) State other three factors necessary for germination. (3mks)
2. (a)What is meant by the term linked genes (1mk)
b) Haemophilia is a genetic condition transmitted through a recessive gene linked to X
chromosome. The normal gene may be represented by XH .
i) What is the genotype of a haemophilic female
ii) A woman who is a carrier for the haemophilia gene marries a normal man. Work out the
phenotypic ratio of their offsprings. (4mks)
iii) Haemophilia is more common in male than in females. Explain the phenomenon (2mks)
3. In an experiment to investigate an aspect of digestion, two test tubes A and B were set up as
shown in the diagram below. The test tubes were left in the bath for 30 minutes. The contents of
each test tube was then tested for starch using iodine solution.

a) What was the aim of the experiment (2mks)

b) What results were expected in test tube A and B (2mks)
c) Account for the results in (b) above (4mks)
4. (a)Complete the table below to show the raw materials, enzymes, and end product of digestion
in the human small intestine
Raw material Enzyme End product
i. Fats Lipase --------and---------------------
i. ------------- Peptidase ---------------------------------
b) Name three food substances in the balance diet that do not undergo digestion (3mks)
c) In which region of the alimentary canal does digestion of lipids start ?

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5. The diagram below shows a portion of a leaf

a) Identify the parts labelled A,C,D

b) State the function of the part labelled G (1mk)
c) i) what would happen to structure G if the epidermal tissue was placed in a concentrated
sugar solution for two hours (1mk)
ii) give a reason for your answer in c (i) above (3mks)
SECTION B:
Answer question 6(compulsory) and either question 7 or 8 in the space provided.
6. In a given malaria prone region, scientists discovered two types of malaria causing Plasmodium
namely, K0 and K1. The people had been using a given type of anti-malaria drug for long time , but
the rate of malaria related deaths seemed to continue increasing. The scientists sampled the
percentage prevalence of the two malaria causing Plasmodium and percentage of death caused by
malaria over a period of 10 years. The analysis showed that K0 represented the original form of the
plasmodium while K1 had a slightly different DNA structure from K0 . the data collected was as
follows
Year % deaths caused by malaria % prevalence of K0 type % prevalence of K1 type
1980 44 60 02
1981 46 58 10
1982 4 52 20
1983 48 50 30
1984 47 46 45
1985 46 40 52
1986 47 30 60
1987 50 16 64
1988 54 08 69
1989 64 04 80
a) Plot a graph of % prevalence of type K0 and K1 against the year (7mks)
b) From the graph determine when the prevalence of both species of plasmodium were equal.
(1mk)
c) From the data, calculate the percentage increase in;
i) Prevalence of K1 from 1985 to 1989 (1mk)
ii) Death rate from 1985 to 1989 (1mk)
d) Account for the result obtained in (c) above (2mks)
e) Account for decline in prevalence of K0 with continous use of said anti-malaria drug. (2mks)
f) Account for increase prevalence of K1 with continous use of the said anti-malaria drug (2mks)
g) Suggest the genetic process that resulted to the emergence of K1 type of plasmodium. (1mk
h) i) Suggest two possible measures that the government could initiate to control the increased
mortality from malaria in the area (2mks)
ii) Suggest the evolutionary theory behind the trend of the two plasmodium in the area (1mk)
7. Discuss:
a). The accommodation of the eye (10mks)
b) The process of hearing in man (10mks)
8. a) Explain how the leaves of terrestrial plants are adapted to the process of photosynthesis.
(10mks)
b) Describe factors that increase the rate of photosynthesis (10mks)

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 MERU CENTRAL.
231/3
BIOLOGY
CONFIDENTIAL.
- About 10 ml of starch solution labeled solution P.
- Two test tubes in a test tube rack.
- 10 ml measuring cylinder.
- Iodine solution.
- 10 % Sodium hydroxide solution.
- 1 % Copper (II) sulphate solution freshly prepared.
- Specimen S- male part of maize flower.
- Specimen R- Hibiscus flower.

MERU CENTRAL
231/3
BIOLOGY
1. You are provided with specimen R and S. Examine the specimen.
a). for each of the specimens, name the mode of pollination and features that adapt the specimen to
the mode of pollination.
Specimen R
Mode of pollination (1 mk)
Adaptive features (2 mks)
Specimen S.
Mode of pollination. (1 mk)
Adaptive features. (2 mks)
b). Draw and label any two parts of specimen R. (3 mks)
c). Using observable features only, state two differences between R and S. (2 mks)
d). With reasons, name the class of spermatophyta to which specimen R belongs. (2 mks)
Class.
Reasons.
2. The photographs labeled R, S, T and V are bones obtained from a mammal. Examine them.
(4 mks)

a). Identify the bones and name the part of the mammalian body from which each bone was
obtained.
b. i). Name the joint between bone S and T at point marked X. (1 mk)
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 ii).Give the characteristics of the joint named in (b) (i) above. (1 mk)
c. i). Name the bone structure labeled Y. (1 mk)
ii).State one function of the bone structure named in C (i) above. (1 mk)
d. i). Using the observable features, give two adaptations of the bone labeled R. (2 mks)
ii).On the bone in the photograph V, draw a diagram of Bone R to show the articulation
between the two bones. (2 mks)
e). Name the part labeled Z in the Bone S and state its function. (2 mks)
f). Name the joint formed by bone T with adjacent bones of its distal end. (1 mk)
3. You are provided with a sample of food labeled P in solution form. Using the reagent provided,
carry out tests on the food sample to identify the type of food substance present. (6 mks)
b). Suggest the regions of the human digestive system where the food tested are digested. (2 mks)
c). State enzymes involved in the digestion of the food present. (2 mks)
d). Name two glands that secrete the enzyme that digest the food substance tested. (2 mks)

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 MERU CENTRAL
231/1
BIOLOGY
MARKING SCHEME.
1. a). Cells;
b). Insects;
2. a). Symbiosis;
b). Fungi has rhizoids which absorb water and mineral salts and provide some to the algae;
Algae has chlorophyll hence manufacture food by photosynthesis and provide some to the
fungi, both benefit;
3. A stiff competation for available resources sets in, resulting in the elimination of one species;
4. a). A- Nucleus;
B- Bud;
b). Budding- A daughter cell is formed from the parent cell;
5. Palisade cell;
Spongy mesophyll cell;
Guard Cells;
6. a). Arachnida;
b). Dicotyledonae;
7. a). Anaphase I;
b). Homologous chromosomes separate at the equator;
Homologous chromosomes start migrating to the opposite poles;
c). It’s the reduction phase that results in haploid sex cells / gametes cells;
8. Na+ - Active transport;
𝑀𝑀𝑀𝑀2+ - Diffusion;
b). Reduce the rate of active transport due to increased rate of respiration/ oxidation of glucose, hence
less energy;
9. a). D- has more nitrogenous waste; more water more mineral salts / ions more oxygen than R;
b). Thicker than other blood capillaries;
10. a). Transpiration;
b). Cut shoot under water / assemble entire set up under water;
Apply petroleum jelly at the stopper;
c). High temperatures increases transpiration rate; hence bubble move faster;
11. Variegated / leaves have less chlorophyll compared to non-variegated leaves; they absorb less light
hence facilitate less photosynthesis;
12. a). Ulna;
b. i). Hinge joint;
ii). Presence of cartilage at the articulation area;
Has synovial fluid;
Presence of ligament holding the two bones;
Movement in one plane only (180 0);
13. Break down organic matter releasing nitrogen to the ecosystem to be re- used by organisms;
14. a). Causes – Causes wearing of mucosa exposing the stomach walls to action of digestive enzymes
and acids;
Management – use ant- acids;
eating non- acid foods;
Surgical treatment of the wounds;
b). Constipation- Caused by reduced peristalsis due to eating food with less roughage;
Management- Eating balanced diet and food with enough roughage;
15. Amnion;
Forms amniotic cavity;
Encloses the foetus and amniotic fluid;

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 Amniotic Fluid;
Provide equatic media for the foetus;
Absorb shocks;
Prevent desiccation of the foetus;
Umbilical cord;
Connect placenta and foetus;
Supply foetus with oxygen and nutrients;
Remove metabolic waste;
16. a). Ribonucleic acid;
Has Uracil base;
b). GGCACG;
17. a). Balance pressure in the middle ears with that of the atmosphere to prevent destruction of the ear
drum;
b). Maintenance of body balance and posture in relation to gravity;
18. Analogous structures, are those with different embryonic origin but have undergone modification to
perform similar functions in different organisms example wings of insects and birds / webbed feet
for frogs and ducks;
Homologous structures, are those with a common embryonic origin but have undergone modification
to perform different functions example the pentadactyl limb of vertebrates;
19. a). Light causes lateral migration of auxin to the dark side; where high concentration of auxin
stimulates rapid cell elongation and faster growth on the dark side than the lit side hence the
shoot bend towards light;
b). Enable plant shoot to grow towards light for photosynthesis;
20. a). i). Androgens (Testosterone)
ii), Oestrogen;
b). No fertilization / no implantation; hence the beginning of new cycle;
21. a). To show that oxygen is necessary for germination;
b). No germination in A; Germination occurs in B;
c). Pyrogallic acid absorved all the oxygen necessary for respiration / lacked energy for growth;
22. a). Tracheoles;
b). Moist to dissolve gases for diffusion in solution form;
Has thin epithelium to reduce distance for diffusion gases;
Has numerous fine tubes to increase surface area for gaseous exchange;
23. a). Moves upward and outwards;
b). Flattens;
c). Contracts;
24. a). Golgi bodies / apparatus;
b). Chloroplasts;
25. Fertilization brings about mixing of different / genetic materials which causes beneficial variation;
- Offspring brings about hybrid vigour;
- Mixing a genetic material forms basis for evolution;
26. The adult and larvae occupy different niches / exploits different food hence do not compete for
resources;
27. a). Very high concentration of Auxins inhibits growth of grass.
b). To delay fruit fall and allow economic harvesting;
c). To activate enzymes for rapid conversion of starch into maltose;
28. 1 mm → 1000 μ m
4 mm
4 𝑥𝑥 1000
= 4000 μ m.
1
4000
Average size of a cell = μ m;
8
= 500 μ m;

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 MERU CENTRAL EXAMINATION.
231/2
BIOLOGY
MARKING SCHEME
1. a). Oxygen (as a factor necessary for germination)
b). Anaerobic respiration;
c). Absorbs oxygen;
d). Glucose enzymes Ethanol + carbon (iv) oxide+ Energy.
e). Alcoholic when in high concentration is poison to plant tissue;
f). Suitable temperature;
- Moisture / water;
- Seed viability;
- Enzymes;
- Hormones;
2. a). Genes located on the same chromosome and are always transmitted together;
b). i). 𝑋𝑋 ℎ 𝑋𝑋 ℎ .
ii).

Phenotypic ratio: 3 normal: 1 haemophiliac

Nb. – Crossing sign must be present
- circles must be complete
- fusion lines must not coverge or penetrate the genete
Accept use of punnet square.
iii). Males lack corresponding allele on the Y chromosome; therefore they cannot be caviers;
3.
a). To investigate the effect of boiled saliva on starch or to show the effect of boiling / denature
enzyme amylase has on starch.
b). A- Brown colour / colour of iodine persist / no change in colour.
B – Blue black colour seen/ colour changed to blue black;
c). A- starch has been digested / broken down / hydrolysed by salivary amylase hence no colour
change;
B- Enzyme amylase denatured hence starch not digested / broken down / hydrolysed;
4. a). Raw material Enzyme End product(s)
i). Fats Lipase fatty acids and glycerol
ii). Peptides Peptidase Amino acids
b). Mineral salts ;
Roughage ;
Vitamin ; Rej. Water.

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c). Duodenum ;
5. a). A- Cuticle ;
C- Pallisade cell ;
D- Vascular bundle ;
b). Gaseous exchange ;
c). i). It will close ;
ii). The guard cell (F)is hypotonic while sugar solution is hypertonic; The guard cell would
loose water across semi- permeable membrane by osmosis into the sugar solution; They
will become flaccid, then walls would draw towards each other closing the stomata;
SECTION B.
6. a).

b). 1984
80−52 28
c). = =7%
4 4
64−46 18
ii). = = 4.5 %
4 4
d). As the population of K1 increase, death rate in the population increase though there was use of
anti- material drug.
e). K0 was naturally selected by drug. it had no adaptation to cope with the continuous used of
drug.
f). K1 was resistance – if had features that unable it not be eliminated by drug- it was resistant to
the drug.
g). Mutation ;
h). - Change of anti- malarial drug;
- Advice on proper use of drugs to avoid resistance;
i). Survival for the fittest or natural selection;
7. a). Distant object- ciliary muscles relax, creating tension on suspensory ligaments/ suspensiory
ligament contract; The les become flattens, less convex, Minimising the refractive power of the
lens, bringing light rays from the object to focus on the retina;
Near object- ciliary muscles contract relaxing tension on suspensory ligaments / lens become
spherical shaped; This increase the refractive power of lens; This brings light rays from near
object to focus on the retina.
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b). Funnel shaped pinna collect sound waves; and direct them to the auditory meatus / ear drum.
Ear drum vibrate and transform sound waves into vibration which are transmitted to the ear
ossicles where they are amplified and transmitted to the oval window. Vibration from oval
window create pressure waves on the fluid / perilymph in the cochlea; Movement of fluid in
cochlea causes sensory hair to be stimulated / touched; generating an impulse; the impulse is
transmitted to the brain via auditory nerve for interpretation on pitch, intensity and direction of
sound.
8 a. Has stomata; to allow in carbon (iv) oxide for photosynthesis; Has thin cuticle ; to allow reduce
the distance through which light moves to reach the photosynthetic tissue; They have
transparent cuticle / epidemis ; to allow light to pass through;
Have broad lamina; to increase the surface are for photosynthesis;
They have chloroplast that contains chlorophyll; to trap light energy for photosynthesis;
Thin palisade tissue is arranged perpendicular / and close to the upper surface; to maximize the
amount of light trapped for maximum photosynthesis;
Their vascular bundles have xylem; that transport water for photosynthesis; and phloem; which
transport manufactured food;
b). Increase in light intensity – Increase in light intensity causes an increase in rate of
photosynthesis up to optimum level. Due to increase in energy used to split the water molecules.
Increase in temperature- Optimum temperature provides energy for enzyme activity. High
temperatures leads to faster enzyme activities hence high rate of photosynthesis.
An increase in carbon (iv) oxide concentration – increase in carbon (iv) oxide concentration
increase reaction with hydrogen ions hence faster rate of photosynthesis.
Availability of water- Water provides the hydrogen ions ( 𝐻𝐻 +) required for glucose formation.

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 MERU CENTRAL
231/3
BIOLOGY
MARKING SCHEME.
1. a). Specimen R
Insect pollination;
Adaptive feature.
i). Large petals to make it conspicuous;
ii). Brightly coloured petals to attract insect (at a distance);
Specimen S.
Wind pollination;
Adaptive feature.
i). Anthers are large/ attached to long filaments to be easily swayed by wind to disperse pollen
grains;
ii). Stigma is large / feathery / hangs outside the flower to increase surface area for trapping pollen
grains in the air;
b). Drawing and labeling any two parts. (2 mks)
c). R S
- Large and (conspicuous) - Small (and inconspicuous)
- Brightly coloured petals - Not brightly coloured petals
- Relatively regular shaped / funnel shaped - No particular shape.
- Stigma enclosed within the flower - stigma hanging outside the flower.
(Award any first two.)
d). Class. Dicotyledonae (Reject wrong spelling)
Reason. Five floral parts / petals.
2. Bone Iadentity Where found.
R Rib; Rib cage / thoracic region;
S Pelvic Girdle; Pelvic / Hip region;
T Femur; Upper Hind limb / leg;
V Thoracic vertebrae; Thoracic / chest region;
b. i). Ball and socket joint;
ii). Permits movement of limb in all planes / direction / 3600;
c. i). Sacrum;
ii). - Provide the surface for muscle attachment of pelvic girdle ;
- Transmits the weight of the body of a stationary animal to pelvic girdle and legs;
- Distributes the weight of the body to all parts of vertebral column during movement;
(Accept first one)
d. i).
- Long to increase surface area for attachment of intercostal muscles;
- Curved to increase space in the thoracic cavity;
- Tuberculum and capitalum for articulation with the thoracic vertebral / tubacular facet and
capitalar dem- facet respectively;
ii). Diagram

Award marks for,

Articulation of tubercolum and capitalum with tubercular facel and capitular demi- facet;

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 Carvature of the Rib;
e). Oburator foramen;
Function; For passage of blood vessels / and nerves ( to the lower limb);
f). Hinge joint;

3. a).
Food substance procedure observation Conclusion
Starch To the solution add few drops of blue- black colour; Starch present ;
iodine solution ;
Protein To the solution add 10 % Blue colour retained Protein absent ;
sodium hydroxide solution then ;
1 % copper (II) sulphate
solution ;
Award marks for correct procedures, observation and conclusion only.
b). Mouth;
Duodenum;
c). Salivary amylase / Ptyalin;
Pacreatic amylase;
d). Sub- mandibular gland;
Parotid glands;

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 CEKENAS
231/1
PAPER 1
TIME: 2 HOURS
1. State the role of mosquito net in the pooter (1mk)
2. Name the causative agent of Tuberculosis (1mk)
3. State the functions of;
a) Ribosomes (1mk)
b) Golgi bodies (1mk)
4. The diagrams below show a red blood cell that was subjected to a certain treatment

At the start of the experiment At the end of the experiment

a) Account for the shape of the cell at the end of the experiment (2mks)
b) What is the name given to the process that occurs when the cell is put into the solution?
(1mk)
5. Study the flow diagram below

Name the substance U, V and W (3mks)

6. Name two Vitamins of which their absence in the diet may cause a dental disease called gingivitis
(2mks)
7. Explain the following observation. Red blood cells lack mitochondria. (1mk)
8. i) State one function of a cover slip in light microscope (1mk)
ii) State the role of revolving nose piece (1mk)
9. Differentiate between dicot stem and monocot stem (2mks)
10. Explain why blood is not normally used for transfusion after one month (1mk)
11. Use the diagram of the heart shown below to answer the questions that follow

i) From the diagram, give a reason to show that X is the left ventricle (1mk)
ii) Name a class of organisms where all members have the heart structure above (1mk)
12. A sample of air was passed through pyrogallic acid and its volume reduced from 8 cm3 to 7cm3.
When it was later passed through lime water, the volume reduced to 4.8cm3.
i) What was the role of pyrogallic acid in this experiment? (1mk)
ii) Determine the percentage of Carbon (IV) oxide in the sample of air (2mks)

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13. A group of students placed a fresh leaf in warm water. They observed that air bubbles forms on the
upper and lower surfaces. More bubbles were formed on the lower surface than on the upper surface.
Explain this observation. (1mk)
14. The diagram below represents a set-up that students used in an investigation

a) Name the physiological process that was being investigated (1mk)

b) i) What observation would be made in boiling tube L (1mk)
ii) Give reason for your answer in b(i) above (1mk)
15. The diagram below shows a graph of body temperature of two different organisms against changing
environmental temperature.

a) State the name used to refer to animal A in terms of thermoregulation (1mk)

b) Explain why organism B is more active than A (2mks)
16. a) Mary suspects that she has diabetes mellitus. Using a sample of her urine describe a school
laboratory procedure she can follow to confirm it is true (2mks)
b) Why is insulin not administered orally? (1mk)
17. a) Name a kingdom in which all members lack centrioles (1mk)
18. The diagram below shows an organism in a certain kingdom

a) State the kingdom to which the organism belongs (1mk)

b) State the mode of nutrition for the organism (1mk)
19. Explain the following observations
a) More water hyacinth plants are found growing along the shore of Lake Victoria than in the deep
waters (1mk)
b) Green plants grow faster in lower altitudes areas than in the higher altitude areas
20. Define;
a) Inter-specific competition (1mk)

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 b) Cyanide is classified as one of the non-competitive inhibitor of enzymes. What is the meaning
of the term non-competitive inhibitor? (1mk)
21. State the roles of each of the following hormones in the process of reproduction in human male
i) Follicle stimulating hormone (1mk)
ii) Luteinizing hormone (1mk)
22. The diagram below is of a flower.

a) Name the agent of pollination for this flower (1mk)

b) Give TWO adaptive features from the diagram to support your answer in (a) above
(2mks)
23. A certain animal had one cell from its alimentary canal observed under light microscope.
A total of 40 chromosomes were seen.
a) State the number of chromosomes in
i) The spermatozoa of this animal (1mk)
ii) One of the cells in the tongue (1mk)
24. The stage-wise process of germination of a seed is shown below

Give a reason why the diagram above represents hypogeal germination (1mk)
a) Account for the change in dry weight of the cotyledon at stage X and Y (2mks)
25. The diagram below shows a life cycle of a cockroach

Egg
Incubation period

Adult Young Nymph

Young Nymph

First week
Second week
Old Nymph

a) Name the hormone that would be at high concentration during the first and second week and their
functions

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i) First week (2mks)
Hormone
Function
ii) Second week (2mks)
Hormone
Function
26. Sickle cell anaemia is a hereditary disease due to a recessive gene which changes normal
haemoglobin (HbA) to abnormal haemoglobin (HbS). The red blood cells of people with sickle cell
anaemia are sickle shaped.
What are the possible phenotypes of the offsprings of a man who is heterozygous and a woman who
is also heterozygous? Show your working. (5mks)
27. The process of gamete formation is represented below

XX
XX

X X
XX

P Q
a) State a reason why the process above represents gamete formation in female mammals
(1mk)
b) Identify the genetic disorder that arise when the following gametes are fertilized
i) P (1mk)
ii) Q (1mk)
28. During a lesson, students observed the structure of a bat, cat and human fore limbs to determine their
evolutionary relationship;
a) State the name given to the structure of the limbs observed by the students (1mk)
b) Name the type of evolution illustrated by the structure of the limbs observed (1mk)
c) What evidence of evolution is illustrated by the limbs? (1mk)
d) Why is Lamarck’s theory on mechanism of evolution not scientifically acceptable? (1mk)
29. a) State the role of Thiobacillus denitrificans in the nitrogen cycle (1mk)
b) State the formula for population estimation using capture recapture method (1mk)
30. Explain why a pregnant woman excretes less urea compared to a woman who is pregnant.
31. a) Why is pancreas said to be a dual gland? (1mk)
b) Name the endocrine tissue in the pancreas (1mk)
32. a) State the major factor in the ‘Global warming’ experienced in the world today (1mk)
b) Suggest two ways of reducing the Global warming (2mks)
33. The diagram below represents a pyramid of biomass derived from a certain ecosystem

Consumer

Producer

a) Suggest the type of ecosystem from which the pyramid was derived (1mk)
b) State the significance of short food chains in an ecosystem (1mk)
Page | 18
34. Name the type of response shown by: (2mks)
a) Leaves of Mimosa pudica when they fold after being touched
b) Sperms when they swim towards ovum
35. The figure below shows a stem of a plant growing round a tree trunk

a) What is the name of the response which causes such a twisted growth? (1mk)
b) What is the importance of the above response? (1mk)

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 CEKENAS
231/2
PAPER 2
TIME: 2 HOURS
SECTION A (40 MARKS)
Answer all the questions in this section in the spaces provided
1. The equation below represents what happens in a certain region of the alimentary canal of a man
X
Water + Substance A Glucose + Substance B
a) Identify the process Y
i) X ____________________________ (1mk)
ii) Y ____________________________ (1mk)
b) Name the carbohydrate A given that B is
i) Glucose __________________________ (1mk)
ii) Fructose _________________________ (1mk)
iii) Galactose ________________________ (1mk)
c) State how process X can be achieved in the laboratory without using enzymes (1mk)
d) Write down two functions of carbohydrates in living organisms (2mks)
2. In Drosophila Melanogaster the inheritance of eye colour is sex linked. The gene for eye colour is
dorminant. A cross was made between a heterozygous red eyed female and white eyed male
a) i) Work out the genotype of F1 generation.
(Use R to represent the gene for eye colour) (4mks)
ii) What is the phenotypic ratio of F1 generation (1mk)
b) What is meant by the term sex linkage (1mk)
c) Identify the trait linked to the Y chromosome only (1mk)
d) Name a disadvantageous gene that offer advantage to a certain group of people (1mk)
3. a) Explain the role of genetic mixing in evolution (2mks)
b) The ability of some members of a species to survive depends on how fit they are. Explain the
expression survival of the fittest (3mks)
c) State three limitations of using fossil records as an evidence of evolution (3mks)
4. a) What factors promote ultrafiltration in the Bowman’s capsule of a human kidney?
(3mks)
b) What is the importance of long loop of Henle in animals in arid areas? (1mk)
c) Explain how the human body deals with excess amino acids (4mks)
5. In an investigation, a student extracted three pieces of pawpaw cylinders using a cork borer. The
cylinders were cut back to 50mm length and placed in a beaker containing a solution. The results after
40 minutes were as shown in the table below.
Feature Result
Average length of cylinders (mm) 56mm
Stiffness of cylinders Stiff
a) Account for the results in table above (3mks)
b) What would be a suitable control set-up for the investigation? (2mks)
c) State three importances of the above process to plants (3mks)
SECTION B (40 MARKS)
Answer question number 6 (compulsory) in the spaces provided and either number 7 or 8 in the
spaces provided after question 8
6. A 10 gram sample of wheat grains was germinated on a moist filter paper. Half of the sample was
grown in a normal daylight and other half in permanent darkness. Samples from each group were
weighed every 48 hours. The fresh mass was found in each case and the following results were
obtained.

Page | 20
 Day Fresh mass seeds grown in Fresh mass of seeds
Light grown in darkness
0 10.00 10.00
2 13.75 13.50
4 16.00 16.50
6 20.00 21.25
8 26.50 26.50
10 34.75 32.25
12 43.75 31.50
14 53.50 28.00
16 61.50 25.00
18 68.25 20.50
a) On the same axes, plot a graph of fresh mass against time (8mks)
b) Account for the differences between two graphs (3mks)
c) What difference would it make to the results of the graph if the dry mass and not the fresh mass was
obtained for the seedlings grown in the dark and in the light? (3mks)
d) What was mass of the seedlings grown in light on the 17 th day? (1mk)
e) State two external conditions necessary for the germination to take place other than water
(2mks)
f) Give three characteristics of meristematic cells (3mks)
7. a) Describe how capture recapture method is used to estimate population of birds of a particular
species in a forest ecosystem (14mks)
b) What assumptions are made using capture recapture method to estimate population (6mks)
8. a) How are the mammalian lungs adapted to their function (10mks)
b) Describe how blood clotting occurs (10mks)

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 CEKENAS
231/3
PAPER 3
TIME: 1 ¾ HOURS
1. You are provided with a substance labeled X in a small beaker. Using the reagents provided, test for
the food substances in X. Record the food tested, procedures, observations and conclusions in the
table below. (9mks)

Food Procedure Observations Conclusions

Substance

2. a) Study the photographs below and answer the questions that follow

i) Identify the type of response exhibited by specimen A (1mk)

ii) What is the survival value of the response you have identified in (2ai) above (1mk)
iii) Identify the phenomenon exhibited by specimen B (1mk)
iv) State the significance of the phenomenon in (b) above (1mk)
v) State 2 characteristics of the seedlings shown in specimen B (2mks)
vi) Explain how the response exhibited by seedlings in photograph C occurred (3mks)

2. b) Study the photograph below showing a certain trait in man

i) Identify the trait exhibited in the photograph above (1mk)

ii) The trait you have identified in (2b) (i) above is sex linked. In which chromosome
is it contained (1mk)
iii) Name any other sex linked trait in males (1mk)

Page | 22
3. a) The photographs below show certain chromosomal mutations

i) Identify the type of chromosomal mutation shown in P and Q (2mks)

ii) Study the photographs below and answer the questions that follow

iii) Give two visible survival adaptive features for the organism in photograph Y and Z
(2mks)
iv) Identify the dentitions exhibited in photograph X and Y (2mks)

3b) i) State the type of evolution represented by structures Q1, R1 and S1 (1mk)
ii) Explain the type of evolution identified in (3b) above (1mk)
ii) Give the evolution term used to describe structures:
Q1, R1 and S1 (1mk)
iv) a) Name class for each Q1, R1 and S1
b) Give two observable reasons for your answer for class S (2mks)

Page | 23
 c) The following is a section of a mammalian kidney

i) Name the part labeled X,Y,Z (3mks)

ii) State 2 homeostatic roles of the organ above (2mks)
iii) Using letter A and B label on the diagram the region where glomerulus and loop of Henle are
located (2mks)

CEKENAS
231/3
BIOLOGY
PAPER 3
TIME: 1 ¾ HOURS
CONFIDENTIAL
Each candidate to be provided with
1. 3 test tubes
2. Hot water bath/means of heating
3. Test tube rack
4. 10ml measuring cylinders
5. 4 droppers
6. Test tube holders
7. Filter paper
8. 10ml suspension (solution X)
9. Distilled water
10. 1% CuSO4 solution
11. 10% NaOH solution
12. Benedicts solution

To prepare X, extract egg albumen from 5 eggs in a beaker. Add 20ml olive oil. Then add distilled
water to make 500ml suspension (label it solution X).

Page | 24
 CEKENAS
231/1
PAPER 1
TIME: 2 HOURS
1. Prevent the dirt form entering the section tube/prevent the organism from being sucked
2. Mycobacterium tuberculosis
3. i) Site for protein synthesis
ii) - Processing/packaging synthesized materials/and transporting of cell materials
- Production of lysosomes/secretion of packaged materials
- Transport of packaged cell materials/glycoprotein
Rj. Assembly of material (Any 1)
4.
a) the red blood cell lost water by osmosis; and shrunk;
b) Crenetion
5. a) Water
b) Oxygen gas rej: oxygen alone
c) Hydrogen gas
6. A; C;
7. To increase surface area for packaging of haemoglobin;
8. i) Exclude dust/contaminants; Prevent dehydration; Hold specimen in position;
OWTTE
ii) Holds the objective lenses in place thus enabling change from one objective lens to another/
Enable rotation changing magnification from low, medium and high power
9.
Dicot stem Monocot stem
Has a pith Lacks a pith
Vascular bundles arranged in a ring (cambium) Vascular bundles scattered
Has a cambium Lacks a cambium
10. Most of the red blood cells will have died;
11. i) Thicker muscles rej: thick muscles
ii) Mammalia
12. i) Absorb/Remove oxygen;
ii) % of CO2 = [7cm3 – 4.8cm3) x 100] ÷ 8cm3; Deny if units omitted
= [0.2 cm3 x 100 ] ÷ 8cm3
= 27.5% Deny if % symbol missing
13. There were more number of stomata on the lower surface than on the upper surface;
14. a) Respiration
b) i) No white precipitate
ii) CO2 has been absorbed by potassium hydroxide
15. a) Poikilotherm; Accept Ectotherm//Ectothermic/Poikilothermic Rej cold blooded
b) Colonize many habitats/can live in any habitat; Is more active both day and night;
16. a) Place 2ml of her urine in a boiling tube
Add equal amount/2ml of Benedict’s solution;
Heat to Boil/heat over a hot water bath;
Green/Yellow/Orange/Brown colour change would show a positive
test/result;
b) it may be digested by enzymes (proteolytic enzymes since it is protein in nature);
17. Plantae
18. a) Fungi (F should be capital)
b) Heterotrophic
19. a) Eutrophication/Enrichment of water by pollutants;
b) Higher concentration of Carbon (IV) oxide; thus higher rate of photosynthesis; conducive/

Page | 25
 Optimum temperatures; thus faster rate of metabolism/Activated enzymes;
20. a) Competition between organisms of different species
b) Inhibitors that permanently combine with the enzyme at the active site
21. i) Initiates the onset of sperm production;
ii) Causes interstitial cells to secrete androgens;
22. a) Wind
b) Long filament; Anthers hanging outside; Feather/Net-like stigma;Smaller bracts to allow the
stigma/anthers to be exposed to wind;
23. i) 20 chromosomes; ii) 40 chromosomes;
24. a) Cotyledon is found below the ground surface; elongated epicotyls;
b) Decreases; since stored nutrients are hydrolyzed to facilitate growth/germination/cell division;
25. i) First week
Hormone – Juvenile hormone
Function – Forms larval cuticle/inhibits moulting metamorphic effects of hormone in the larval
stage
ii) Second week
Hormone – Ecdysone / moulting hormone
Function – moulting to allow growth and metamorphosis
26.

27. a) Involves X chromosomes only;

b) i) Turner’s Syndrome;
ii) Klinefelter’s Syndrome;
28. a) Pentadactyl structure evolution
b) Divergent evolution
c) Comparative anatomy
d) Phenotypically acquired characteristics cannot be inherited
29. a) Cause denitrification
b) Population = [First Marked X Second Capture] ÷ Marked Recaptured
REJ Abbreviations
30. Amino acids are used in the formation of foetal tissues; thus has less excess to be eliminated;
31. a) Secretes hormones and enzymes/has endocrine and exocrine functions;
b) Islet of Langerhans;
32. a) Carbon (IV) Oxide;
b) Reducing emission of Carbon IV oxide and other green house gases;
Reducing use of wood and other fossil fuels;
Planting more trees;
33. a) Aquatic ecosystem;
b) The shorter the food chain, the more energy can be derived from it, hence the larger the
population it can support;
34. a) haptonasty/thigmonasty
b) Positive chemotaxis
35. a) Haptotrophism/thigmotropism
b) Provides support to climbing plants so as to trap light and carbon (IV) Oxide

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 CEKENAS
231/2
BIOLOGY
PAPER 2
MARKING SCHEME
1. a) i) X – Hydrolysis;
ii) Y – Condensation ; (2mks)
b) i) Maltose;
ii) Sucrose;
iii) Lactose; (3mks)
c) Heating a disaccharide with a dilute acid (such as hydrochloric acid); (1mk)
d) - Source of energy during respiration;
- Act as structural components e.g. chitin;
- Act as stored food e.g. starch in plants and glycogen in animals; (2mks)
2. a)i)

(4mks)

ii) F1 phenotypic ratio

Red eyed female: white eyed female: red eyed male: white eyed male (1mk)
1 : 1 1 : 1
b) Sex linkage – location of genes on the sex chromosome hence inherited together with those
determining sex (1mk)
c) Premature baldness; (1mk)
Hairy pinnae; acc. Tuft of hair in the ear (mark any one)
d) Sickle cell anaemia; (1mk)
3. a) It brings variation;
It leads to formation of hybrids; (2mks)
b) Organisms tend to produce more offspring than the environment can support hence they must
struggle to exist;
Individuals that have favourable characteristics will have a better chance of survival in the struggle;
and reproduce; (3mks)
c) They have been distorted by earth movements and sedimentation thus some parts are not well
placed;
Some links are missing;
Soft parts are never preserved hence cannot be traced; (3mks)
4. a)
- Afferent arteriole wider than efferent arteriole creating high pressure;
- Dense network of blood capillaries in the glomerulus create high pressure
(since the lumen of capillaries is narrow) ;
- High pressure of blood from renal artery entering glomerulus; (3mks)
b) It enhances the process of reabsorption of water; (1mk)
c) Excess amino acid are deaminated; where the amino group is reacted with hydrogen to form
ammonia;
Ammonia is toxic and combines with Carbon (IV) oxide to form less toxic area;

Page | 27
 Urea is then excreted in urine through the kidney; (4mks)
5. a) The solution was hypotonic/less concentrated compared to cellsap of pawpaw cylinder cells;
Acc. the converse
- The tissue/cells gained water by osmosis; becoming turgid/longer/stiff;
- Rej. use of potato instead of pawpaw (3mks)
b) - Pawpaw cylinder of same size/length placed in isotonic solution;
Rej. if same length and isotonic is missing
- Boiled pawpaw cylinder of same size/length placed in similar solutions; (2mks)
c) Absorption of water from soil;
Support;
Opening and closing of stomata
Feeding in insectivorous plants; (mark first 3) (3mks)
SECTION B (40 MARKS)
Answer question number 6 (compulsory) in the spaces provided and either number 7 or 8 in
the spaces provided after question 8
6. b) Seedlings grown in darkness – fresh weight increases upto day 11 due to
absorption of water; then it begins to drop due to lack of photosynthesis;
Seedlings grown in light: fresh weight increases steadily even after day11 due to
continued photosynthesis; (3mks)
c) In the dark – the dry weight would drop immediately, due to lack of photosynthesis; in the
light; the dry weight would drop; before the leaves start to carry photosynthesis; (3mks)
d) 65.0 + 0.5; (1mk)
e) Optimum temperatures, rej. temperature alone
Oxygen; (2mks)
f) Dense cytoplasm; thin cell wall;
Small in size;
Lack vacuoles; Mark 1st three (3mks)

7. a) Traps are laid; to capture/trap/catch birds;

The birds are counted; marked using a water proof ink/paint; recorded; as first marked (FM); and
then released (into the forest); After one day/24hrs/48hrs; trap are laid again; to capture the birds
again in the second capture(SC); and count the marked; and the unmarked; as marked recaptured
(MR);
Page | 28
 Proceed to calculate the population (P) as
P = FM x SC
MR (14mks)
b) - No immigration and emigration of birds; (OWTTE)
- The released organism mix freely/randomly; with the rest of population;
- The mark/ink paint used doesn’t alter the animal’s behavior;
- Enough time for organisms to mix freely;
- Population doesn’t change within the period of study;
Acc . no reproduction/death (6mks)
8. a) Lungs are made up of (numerous) air sacs/alveoli;
The alveoli are many; to increase surface area for gaseous exchange;
The alveoli are moist; to dissolve respiratory gases; hence faster diffusion;
Alveoli have thin epithelium; that reduce distance; covered by respiratory gases; hence faster
diffusion; (10mks)
b) When a blood vessel is cut/ligatured; platelets are exposed to air; then they burst/rapture to release
thrombokinase /thromboplastin (enzyme); which converts inactive prothrombin; to active thrombin;
Thrombin converts the soluble fibrinogen; into insoluble fibrin; which forms a meshwork at the
wound; this dries to form a scab/dries; preventing loss of blood; (10mks)

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 CEKENAS
231/3
PAPER 3
(PRACTICAL)
TIME: 1 ¾ HOURS
1.
Food Procedure Observations Conclusions
Substance
Put substance X in a test tube, Colour of Copper Proteins present;
Protein(s) add (equal amount of) sodium Sulphate turns
hydroxide the Copper Sulphate; purple/violet;
dropwise;
To solution X1 add Benedict’s Blue colour is Reducing sugar
Reducing sugar(s) solution and heat; retained/ No colour absent;
change;
Lipids Rub/smear X on a filter paper (Permanent) Lipids present;
Rej. oil/fat dry the spot; Transclucent
mark/sport is
formed;
(9mks)
2. i) Haptonasty/Thigmonasty (1mk)
ii) Enables plants in areas that has less nitrates to acquire nitrate (1mk)
iii) Etiolation (1mk)
iv) Enables plants to acquire light (1mk)
v) Stem is white
Small leaves
Thin stem
The stem is long /long internodes (2mks)
vi) Auxins migrate from light to dark side; bringing more elongation/faster/rapid elongation; the
tip of shoot bend towards light (3mks)
2. i) Tuft of hair in the pinna/hairy pinna (1mk)
ii) Y -Chromosome (1mk)
iii) Premature baldness (1mk)
3. i) Identify the type of chromosomal mutation shown in P and Q (2mks)
P – Duplication
Q – Deletion
iii) - Strong jaw
- Sharp incisors and canine/sharp teeth
- Eyes (2mks)
iv) X - Heterodont
Y – Homodont (2mks)
b) Convergent evolution (1mk)
c) The structures from the different embryonic origin but modified to perform same/similar
function (1mk)
i) Q1 - Mammalia
R1 – Insecta
S1 – Aves (3mks)
ii) Have beaks
Have feathers
Have talons/claws
Fore limbs modified to wings (2mks)
c) X – Renal artery
Page | 30
 Y – Renal vein
Z – Pelvis (3mks)
ii) Excretion
Osmoregulation (2mks)
iii)

Page | 31
 KIGUMO CLUSTER
PAPER 1
BIOLOGY
1. Explain how the following factors increase the rate of water loss from a plant
a) Broad leaf stamina (1mks)
b) Wind (2mks)
2. Name the branch of Biology that deals with study of the following
a) Cells (1mks)
b) Development of techniques for the application of biological processes (1mks)
c) Structure of tissues (1mks)
3 a) Name the cell responsible for carbon (IV) oxide transport in human beings (1mks)
b). Give two advantages of carbon (IV) oxide transport by the cells named in (a) above
4. How are the following structures important in the human body
a) Pericardium (3mks)
b) Pleural membrane (2mks)
5. Name the organelle that perform the following functions in a cell.
a) Manufacture of ribosomes (1mks)
b) Transport of cell secretions. (1mks)
c). State two functions of the body tube of the light microscope. (2marks).
6. Name the carbohydrates that make up the following structures in living organisms
a) Exoskeleton of insects (1mks)
b). Collenchyma tissues (1mks)
7. State two importance of irritability to living organisms (2mks)
8. Explain why the bat is classified as a mammal yet it flies (2mks)
9. The table below shows the percentage concentration of certain substances in blood plasma ,
glomerular filtrate and urine in a human being at a particular time
Percentage concentration
Substance Blood plasma Glomerular filtrate Urine
Glucose 0.023 0.02 0.0
Water 92.70 92.70 96.08
Protein 5.69 0.0 0.0
Urea 0.087 0.098 2.6
a) Explain the likely impact on the composition of urine in case of the following
i) Vigorous physical exercises (2mks)
ii) A meal rich in proteins (2mks)
b) Name the processes responsible for
i) presence of glucose in the glomerular filtrate (1mks)
ii). Absence of glucose in urine. (1mks)
10. In investigating a certain physiological process, students set up the apparatus as shown below
and made observations after 30 minutes as illustrated.

Page | 32
1. Name the physiological process being investigated (1mks)
b). Account for the observation made at the end of experiment (3mks)
c). State the likely identity of G. (1mk)
11. In an investigation students set up the apparatus below in the laboratory and made observation
after 72 hours

- Explain the inclusion of the following components would affect the mouse in the experiment
i) Light (2mks)
ii). Sodium hydroxide solution (2mks)
- State why the students preferred to use a bell jar and not a tin box in the experiment. (1mks)
12. Below are diagrams representing developmental stage of three different vertebrate

a) State the evidence of evolution illustrated by the vertebrates in the diagram. (1mks)
b) Suggest why the structure labelled J has been retained throughout the evolution of fish.
(2mks)
c) State two major advantages evolution has given humans over most of the other animals.
(2mks)
13. Name three structures of the skin essential for its homeostatic function. (3mks)
14 a). Name the process that takes place around the 14th day of the menstruation cycle.
(1mks)
b). Under which conditions would the cycle be interrupted? (2marks).
15. Describe how epigeal germination occurs (3mks)
16. State two characteristics of the kingdom Monera that are not found in the Kingdom Animalia.
17. Name the causative agents of the following diseases
a) Amoebic dysentery (1mk)
b). Malaria (1mk)
18. In an experiment students soaked maize seeds in water for 48 hours at room temperature and
tested them for reducing sugars
a) Explain the reasons for soaking the seeds (2mks)
b) State the observations made by the students during the food test (1mk)
Page | 33
c). Explain the effect of soaking the seeds in hot water on the food test results (2mks)
19. State the role of tears in the human eye. (2mks)
20. Explain the effect of a severe drought on the population of organisms in the ecosystem.
(3mks)
21. On a colder day, an infant must be dressed in much warmer clothing than an adult. Explain.
(2mks)
22. Give two causes of eutrophication. (2mks)
23. A patient with blood group A dies shortly after transfusion with blood group B. Explain
24. If food containing a lot of starch is chewed for a long time it may leave a sweet taste in the
mouth. Explain (2mks)
25 a). Name the bones that articulate to form a ball and socket joint at the hip. (2marks).
b). Name the structure that prevents overstretching of the fore limb in human. (1mark).

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 KIGUMO
231/2
PAPER 2
Time: 2 Hours
SECTION A (40 Marks)
Answer ALL the questions in this section
1. In a certain plant species which is normally green, a recessive gene to colour (n) causes the
plants to be white in colour. Such plants die at an early age. In the heterozygous state, the plants
are pale green in colour but grow to maturity.
a) Give reasons for the early death of the plants with the homozygous recessive gene. (2 marks)
b) If a normal green plant was crossed with the pale green plant, what would be the geneotype of
the first filial generation (F1 generation)? Show your working. (4 Marks)
c). If heterozygous plants were self-pollinated and the resulting seeds planted, work out the
proportion of their offspring that would grow to maturity. (2 Marks)
2. A student wanted to observe human red blood cells under a light microscope. He put l0ml of
solution X, Y and Z in three boiling test tubes. The solutions were of different concentration. In
each of the test tubes he put three drops of blood sample. The experiment was left to stand for
30 minutes. He placed one drop of solution X on glass slide and observed under the microscope.
The same procedure was repeated for solutions Y and Z. He made the following observation.
Solution Observation
X Normal Cells
Y Wrinkled Cells
Z No cells observed
(a) What was the physiological process investigated? (1mk)
(b) Explain why red blood cells observed in solution Y were wrinkled. (3mks)
(c) A 3cm long piece of kale (sukuma wiki) stem was cut halfway along its length as
shown below.

i) If the piece was placed in solution Z for 30 minutes, its shape changed. Using a pencil draw a
diagram in the space provided to show the expected change. (1mk)
ii) Explain the results obtained in c(i) above. (3mks)
3. During an ecological study, students collected and marked 120 ants and released them. After 48
hours, the students captured another 90 ants, 20 of which had been marked previously.
a) How many ants were there in the compound? Show your working. (3mks)
b) What are the limitations of this method in sampling animal populations? (4mks)
c) State other method which could be used to determine the population. (1mk)

Page | 35
4. The diagram below represent set ups arranged by a group of students investigating certain
characteristics of enzymes

The students tested the contents for sucrose in the three test tubes after 30 minutes.
a) In which of the three set ups was the test for sucrose negative? (1mk)
b) Giving a reason in each case, state the test tubes in which the test for sucrose was positive.
c) State two characteristics of enzymes the students were investigating. (2mks)
d) Define the term competitive inhibitor as used in study of enzymes. (1mk)
5. The diagram below shows a section through the mammalian skin.

(a) i) Name the substance produced by the part labelled G. (1 mark)

ii) State two functions of the substance named in 5(a)(i). (2 marks)
(b) Name the part labelled E. (1 mark)
(c) Explain the function of the part labelled F to the mammal. (2 marks)
d i) Name one part of the human body where the cornified layer is thickest. (1mark)
ii) Give a reason for your answer in (d)(i) above. (1 mark)
SECTION B (40 MARKS)
Answer question 6 (compulsory) and either 7 or 8
6. Ten batches each containing 50 maize seeds were placed separately in trays containing moist
soil. The trays were kept at different temperatures in a greenhouse. After ten days, the
percentage germination in each batch was found to be as follows:
Temperature (oC) Percentage germination (%)
0 0
5 0
10 4
15 9
20 16
25 32
30 60
35 88
40 5
45 0

Page | 36
a) Using a suitable scale, plot a graph of percentage germination against temperature.(6mk)
b) Account for germination percentage at:
(i) 0oC (2mk)
ii). 35oC (2 marks)
iii). 45oC (2marks)
c). Calculate the number of seeds that germinated at 25oC. (1mark)
d) Other than temperature, state two other abiotic factors that affect germination. (2marks)
e). State the importance of each of the factors named in (d) above. (2mk)
f). Explain the biological importance of dormancy in seeds. (3mk)
7. a) Explain how herbivores are adapted to their mode of feeding. (10mks)
b) Describe the process that occurs after the pollen grain lands on the stigma of a flowering
plant until fertilization occurs. (10marks).
8 a) Describe the process of inhalation in a man. (8mks)
b) Explain how bony fish are adapted to their habitats (12 marks)

KIGUMO
231/3
PAPER THREE.
CONFIDENTIAL

Each candidate will require the following

- 10𝑐𝑐𝑐𝑐3 of dilute hydrogen peroxide
- Scapel
- 1 piece of medium Irish potato
- 1 boiling tube
- Source of heat
- Small amount of corn oil labeled Z
- 2𝑐𝑐𝑐𝑐3 of milk in test tube labeled as solution C
- 1 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 𝑋𝑋
- 3 clean test tubes
- 2𝑐𝑐𝑐𝑐3 of sodium hydrogen carbonate solution
- Distilled water
- Beaker
- Wall clock
- 3 labels

Page | 37
 KIGUMO
231/3
BIOLOGY
PAPER 3
TIME 1 ¾ HOURS
1. Take 2 clean test tubes and into each add 5𝑐𝑐𝑐𝑐3 of dilute Hydrogen peroxide. Label the test tube
as A and B. Cut 2 cubes of irish potato measuring abut 1𝑐𝑐𝑐𝑐3 each. Boil one cube in a boiling
tube with some water for about 5 minutes. Drop the boiled cube into test tube A and unboiled
cube into test tube B at the same time. State your observation
i) test tube A (1mark)
ii) test tube B (1mark)
b) Account for your observation in
i) Test tube A (2mark)
ii) Test tube B (2marks)
c). Take a small amount of substance Z provided and add to it 2𝑐𝑐𝑐𝑐3 of sodium hydrogen
carbonate
i) State your observation. (1mark)
ii) Which process in the body is illustrate above (1mark)
iii) State the part of the body where the process takes place (1mark)
iv) What is the significance of the process? (1mark)
d) Put 2𝑐𝑐𝑐𝑐3 of liquid labeled as C into a test tube. Squeeze some juice from specimen X into a
beaker. Drain some of the juice into a dropper. Add 3 drops of the juice into the test tube with
solution C.
i) State your observation (1mark)
ii) State the part of the human body where the process demonstrated above occurs and the enzyme
that carries out the process.
Part of body (1mark)
Enzyme (1mark)
iii) Which hormone stimulate the production of the enzyme state in (ii) above? (1mark)
2. The photography below shows four specimens labeled P, Q, R and S which were obtained from
same animal. Examine them

a) With reasons identify P and Q (4marks)

b) Based on their structure suggest the function of specimen P and Q (2marks)
c) In specimen P name the two parts labeled A and D (2marks)
d) Using observable features, state the differences between specimen R and S (2marks)
e) Explain how specimen S is adapted for its function (2marks)
f) With reasons, suggest the mode of feeding of the animal from which the specimens were
obtained (2marks)
g) Using observable features only, state:
i) One similarity between specimen Q and R (1mark)

Page | 38
ii) Two differences between specimen Q and R (2marks)
3. The diagram below shows parts of a particular type of plant encountered by students in a
mountainous area

ai) Name the sub division and class the specimen above belongs to
Sub division (1mark)
Class (1mark)
ii) Give a reason for placing it in the sub-division named in a (i) above (1mark)
b). which of the structures labelled above represents a part of the plant where the formation of the
following takes place;
i) Male gametes. (1mark)
ii). Female gametes. (1mark)
c i) Which observation feature of the leaves shows that the plant is a xerophyte (1mark)
ii) State two other features of the leaf of the plant that adapts it to xerophytic life (2marks)

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 KIGUMO CLUSTER
PAPER 1
PAPER ONE
MARKING SCHEME
1.
a) Increase surface area which water vapor is lost.
b) Carries away water vapor thus increases saturation deficit
2.
a) Cytology
b) Biotechnology
c) Histology
3.
a) Red blood cell/erythrocyte.
b) No change in blood pH
Faster due to presence of carbonic anhydrase
4.
a) Hold the heart in position
Prevent over dilation of the heart
Secrete pericardia fluid
b) Hold lungs in position
Secretes pleural fluid that lubricates the lungs.
5.
a) Nucleolus
b). Golgi bodies
c). Hold revolving nose piece/objective lens in place;
Hold the eye piece lens/ocular lens in place;
6. a). Chitin
b). Cellulose
7. Enables living organism avoid harmful conditions;
Enables living organisms obtain favorable conditions;
8 a). Has mammary glands
b). Body covered with fur
c). Heterodont dentition
d). Has sweat glands
9.
a.
i) Less water and urea since some is eliminated through skin as sweat.
ii) Increased amount of urea in the urine due to determination of amino acids from proteins
b.
i) Ultrafiltration
ii) Selective reabsorption Rej. Selective absorption or reabsorption alone
10.
(a) Osmosis
(b) Solution E was hypertonic compared to solution F by osmosis water molecules moved through
semipermeable membrane G hence the decrease in volume of solution F
(c) Semipermeable membrane
11.
a.
Page | 40
i) Light enables the potted plant to photosynthesis producing oxygen which is inhaled by the
mouse
ii) Absorb carbon (iv) oxide denying the plant raw material to photosynthesis hence suffocating of
the mouse/ no oxygen.
b. Bell jar is transparent allows penetration of light for the plant to photosynthesis
12.
a) Comparative embryology
b) Fish remain in aquatic habitat well developed tail for propulsion /movement
c) Ability to think binocular vision
Ability to walk on two/ upright vision
Ability to communicate through speech
13. Blood vessels; hair; sweat glands; nerve endings; erector pili muscles;
14. a) Ovulation;
b). Sickness;
Change in environment;
Pregnancy/implantation/conception;
Emotional instability;
15. Hypocotyl elongate faster than the epicotyl;
Pushing cotyledon above the ground
16. Prokaryotic /lack nuclear membrane
Possess cell wall; unicellular; lack membrane bound organelles;
17.
a) Entamoeba Histolytica
b) Plasmodium ovale/ falciparum /vivax/ malariae
18.
a) To soften seed coat for entry of water to activate enzymes action starch
b) Color change to yellow/ orange/ brown;
c) Hot water has high temperature which would denature the enzymes giving negative results no
color change
19. Moisten the eyeball/eye
Washes of dust particles from the eye
Antiseptic
20. Plant dies; reducing food for organism, which lead to death migration forcing a decrease in
pollution
21. Infant has a large surface area to volume ratios hence would lose more heat to the surrounding
than the adult
22. Wash away of inorganic fertilizer from land into water bodies
Dispose of raw sewage into water bodies
Discharge of industrial material into water bodies
23. Patient has antibody b while donor has antigen B; antigen- antibody reaction occurs leading to
agglutination of red blood cells of the patient
24. Chewing increases surface area or food for action of salivary amylase; to breakdown starch to
maltose that is a reducing sugar with a sweet taste;
25. a). Pelvic girdle;
femur;
b). Olecranon process;

Page | 41
 KIGUMO
MARKING SCHEME
231/2
BIOLOGY
PAPER 2
1 a) The leaves do not have chlorophyll; They do not manufacture food (by photosynthesis);
thus no development of tissues. (2 marks)
b)

Fi Filial generation NN Nn Nn Nn
2 : Homozygous green
2 : Heterozygous
c)

2. (a) Osmosis; (1 mark)

(b) Solution Y is hypertonic to the red blood cells; water moved from cell to solution Y by
osmosis; Cell became flaccid/ shrinks; (3mark)
c), (i)

ii) Cortex cells/ cortical cells absorbs water by osmosis; expanding /curving away to the epidermis;
epidermal cells are water proof; (3 marks)
3. a) Approximate population =
No. of organism in first catch × No. of organisms in sec ond catch
No. of marked organisms recaptured
𝐹𝐹𝐹𝐹×𝑆𝑆𝑆𝑆
i.e 𝑃𝑃 = ;
𝑀𝑀𝑀𝑀
120×90
= ;  540 ants; 
20
b) Does not consider migration of organisms into and out of study area.
- Does not consider the effect of paint used in marking on the animals behaviour
- Released animals may not mix freely with the remaining population.
- Marked organism may not have adequate time to mix with the rest.
- Does not consider the effect of weather on the organisms behavior (any 4)
c) - Quadrat method
- Belt transect method
Page | 42
 - Line transect method
4. The diagram below represent set ups arranged by a group of students investigating certain
characteristics of enzymes
a). Set up B;
b). Set up A; – sucrose was not broken down because there was no sucrase enzyme; lactose cannot
breakdown sucrose
Set up C; Sucrose was not broken down because the enzyme sucrase was inactivated by low
temperatures;
c) - Enzymes are affected by temperatures;
- Enzymes are substrate specific;
d) Substances that compete with the substrate for the active sites of the enzyme slowing down rate
of reaction; OWTTE
5. a) i) Sebum;
ii) Keeps the skin moist/supple;
Acts as an antiseptic;
makes the skin/hair water repellent; mark the first two
b) Sweat pore;
c). Thermoregulation; lies flat or erects (on the skin) when hot/cold to conserve heat or emit excess
heat;
d i). Sole of the feet/palm of hand;
ii) they encounter high friction;
SECTION B (40 MARKS)
Answer question 6 (compulsory) and either 7 or 8

b i). Enzymes are inactive due to low temperature; hence no hydrolysis of food in the
endosperm/ no respiration to provide energy for growth;
ii) This is the optimum temperature for enzyme activity; hence maximum growth is
experienced;
iii). High temperature beyond the optimum hence enzymes get denatured; hence no hydrolysis
of food takes place and no energy is produced for growth;

Page | 43
c). 100% = 50 seeds germinated
32% =?
32/100x 50
16 eeds
d). Water; oxygen; Light; any two
e). Water
i) Activates enzymes;
ii) Medium for enzyme activity;
iii) Hydrolyses stored food;
iv) Medium of transport of soluble food substances;
v) Softens the seed coat Award only for the first correct
Oxygen
Oxidizes food to generate energy for germination /growth/respiration;
f). i). Provides seeds with adequate time for dispersal so that they germinate away from the
parent plant;
ii). Enables seeds to survive adverse environmental conditions without depleting the stored
food;
iii). Provides enough time for the embryo to mature fully before it can germinate/respiration;
7. a) Herbivorous mammals
These are animals that feed on exclusively on plants; they are faced with a major problem of
digesting plant tissues made up of tough cellulose materials that form the cell wall of plant cell;
They lack incisors in the upper jaw instead they have honey pad; against which grass is pressed
and cut with incisors in the lower jaw; Incisors in the lower jaw are well developed with sharp
chisel edge; for cutting of grass. They have no canine teeth instead they have a gap called
diastema; which helps to hold the grass before pushing it to the premolar and molar for
grinding.
The molar and premolar have ridges /cusps; in the grinding surface; which slides over one other;
with the grass in between hence is grounded into tiny particles;
The enamel of the molars and premolars have a large surface area for grinding food;
The joint of the jaw bone are loose; allowing circular jaw motion in the horizontal plane ideal
for grinding food
Their premolar and molar have open enamel in the crown allowing continuous growth of teeth
throughout their life; hence counteracting the wear and tear due to grinding; they have long and
elaborate digestive system; for effective breakdown of indigested food eg Ruminants have four
stomach chambers with rumen where digestion of cellulose takes place due to the presence of
bacteria that secret enzyme cellulose;
Total 16 max 10
b) The pollen tube start to germinate downwards along the style; a tube nucleus keeps at the tip the
pollen tube whole role is to control growth of the pollen tube; while generative nucleus follow
behind, energy for growth is obtained from tissues of the style; and growth depends on
compatibility between the style and the pollen grain; generative nucleus divides mitotically
forming two male nuclei; the pollen tube enter the embryo sac through the micropyle; after
which the tube nucleus disintegrate; one male nuclei fuses with the egg cell to form a diploid
zygote; while the other male nuclei fuses with the polar nuclei to form a triploid nuclei; which
form primary endosperm;
8 a). External intercostal muscles contract; while internal intercostal muscles relax; ribcage moves
upwards and outwards; muscles of diaphragm contract hence flattens; volume of thoracic cavity
increases and pressure decreases; than the atmospheric pressure; higher air pressure in the
atmosphere forces air into the lungs; and the lungs inflate;

Page | 44
b) Have streamlined bodies; to reduce friction; body is covered with scales; which overlap
backwards; to reduce friction; skin produces mucus; which covers the body making it slippery;
reducing friction; have swim bladder; which stores air; for buoyancy hence make the fish float;
myotomes/muscle blocks; that contract alternately; for forward thrust in water; lateral line
system; on either side of the body which is sensitive to pressure and water currents; possess
fins; that are used for locomotion: tail/caudal fins; for propulsion; dorsal; and anal fins; prevent
rolling; pectoral fin; used for breaking/steering; prevents yawing/side to side movement;
controls pitching; pelvic fins; for steering/pitching; max. 12 mks

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 KIGUMO
PAPER 3
MARKING SCHEME
213/3
1. a) i) No bubbles/effervescence 1mk
ii) Bubbles/effervescence/ foam formed. 1mk
b) i) Catalase enzyme denatured by high temperature (above optimum) hence no reaction.
ii) Catalase enzyme, broken down hydrogen peroxide into water and oxygen gas hence
bubbles. 1mk
c) i) Broken down into small droplets. 1mk
ii) Emulsification. 1mk
iii) Duodenum. 1mk
iv) Increase the surface area for enzyme lipase to speed up the breakdown of lipids to fatty
acids and glycerol. 1mk
d) i) Liquid C forms solid particles / liquid curdles. 1mk
ii) Part of body – stomach. 1mk
Enzyme – Rennin 1mk
iii) Gastrin hormone. 1mk
2. a) P: Molar tooth. (1mk)
Reason: Biting surface is wide and has cusps/ridges (1mk)
Presence of three roots.
Q: Incisor 1mk
Reason: Biting surface is chisel shaped / wedge shaped. (1mk)
b) P: Grinding and crushing of food. (1mk)
Q: Bitting and cutting food. (1mk)
c) A: Cusps/ridges. (1mk)
D: Root.
d) R has appointed biting surface while S has a broad biting surface with cusps/ridges.
R has one root while S has two roots.
R is smaller than S. (2mks)
e) It has cusps/ridges on it’s biting surface; that enable crushing and grinding of food. (2mks)
f) Mode of feeding: Herbivorous. 1mk
Reasons: - Specimen P(molar) and S premolar have unevenly worn out crowns forming
cusps/ridges for crushing and grinding vegetation. 1mk
- Specimen Q (incisor) has broad and chisel shaped biting surface for gripping and cutting
vegetation.
- Specimen R (canine) is reduced in size (2mks)
g) i) Both have one root (1mk)
ii) Q has a chisel shaped/wedge – shaped biting surface while R has a pointed surface.
Q is larger than R.
3. a) i) Sub- division – Gymnospermaphyta (1mk)
Class – Coniferales (1mk) REJ if not starting with capital letter.
ii) Presence of cones (1mk)
b) i) K (1mk)
ii) N (1mk)
c i) Needle leaves; ACC Leaves modified into thorns (1mk)
ii) Thick waxy cuticle to offer a long distance water molecules cover hence to reduce/ prevent
cuticular transpiration ; sunken stomata to reduce direct exposure to atmosphere hence lower
rate of stomatal transpiration; fewer stomata thus reduced surface area over which transpiration
occurs. (2mks)
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 KIENI EAST
231/1
BIOLOGY
PAPER 1
1. (a) Name the branch of Science that deal with the study of living things. (1 mark)
2. (a) State the function of a mirror in a light microscope. (1 mark)
(b) Give one reason why the coarse adjustment knob should not be used to lower the high
power objective (1 mark)
3. (a) State two roles of mucus in the stomach. (2 marks)
(b) Explain how age determines a person’s energy requirement. (2 marks)
4. (a) State the function of cristae in mitochondria. (1 mark)
(b) The diagram below represents a cell organelle.
Y

X
i) Name the part labelled Y. (1 mark)
ii) State the function of the part labelled X. (1 mark)
5. An experiment was carried out to determine the rate of transpiration in three plants A, B and C.
Plant A and B belonged to different specie while plants B and C belonged to the same species.
Plant C had all its leaves removed. The three plants were of similar size and were exposed to
the same environmental condition. The results are as shown below in the graph.

Plant Weight C
(gm)

A
B

0 30 60 90 120
Time in (minute)
(a) Suggest possible environment conditions under which experiment was carried out between
30 to 60 minutes. (1 mark)
(b) Account for the results obtained for plant C. (2 marks)
(c) Suggest the habitat for plants A and B. Give reasons for your answer. (4 marks)
Habitat Reason
6. State three ways in which blood capillaries are structurally adapted to their functions.(3 marks)

Page | 47
7. The diagram below represents a set up that students used in an investigation.

(a) Name the physiological process that was being investigated. (1 mark)
(b) State the role of potassium hydroxide in flask K. (1 mark)
(c) Account for the observation in boiling tube L and flask N. (2 marks)
8. Giving a reason in each case, name the class to which each of the following organisms belong.
(4 marks)
Bean plant
Bat
9. Explain how the following prevent self-pollination.
(i) Protandry (1 mark)
(ii) Self - sterility (1 mark)
10. What is the function of the following structure in the human reproductive organs?
(a) Fallopian tubes (1 mark)
(b) Epididymis (1 mark)
(c) Scrotal sac (1 mark)
11. (a) What is meant by the term non-disjunction? (1 mark)
(b) Give an example of genetic disorder caused by:-
(i) Non - disfunction (1 mark)
(ii) Gene mutation (1 mark)
12. The diagram illustrates a nerve cell.

(a) Name the type of nerve cell illustrated. (1 mark)

(b) Give a reason for your answer in (a) above. (1 mark)
(c) Identify the part labelled J. (1 mark)
(d) State the function of the part labelled G. (1 mark)
13. (a) Distinguish between homologous and analogous structure. (2 marks)
(b) Explain the term continental drift as used in evolution. (2 marks)
14. State three features of vertebra. (3 marks)
15. The diagram below represents a stage of growth in two different seeds

Seedling A Seedling B
a) Identify the type of germination exhibited by seedling A and B (2 marks)
Seeding A
Page | 48
 Seeding B
b) State role of oxygen in germination. (1 mark)
16. Define the following terms as used in ecology. (3 marks)
i) Ecological niche
ii) Biosphere
iii) Population
17. Classification as a topic in Biology should not be ignored. Explain. (3 marks)
18. What is the difference between members of taxon species and members of other taxa.?
(1 mark)
19. (a) What name is given to the difference in concentration of two areas which result in
diffusion? (1 mark)
(b) What is the effect of the above on the rate of diffusion. (2 marks)
20. Explain how temperature affects the rate of active transport. (2 marks)
21. Sugar appear in the urine of a diabetic person. Explain. (3 marks)
22. State the importance of the following plant excretory product. (3 marks)
Rubber
Papain
Quinine
23. The diagram below shows the exchange of gases in alveolus.

a) State how the alveolus is adapted to their function. (3 marks)

b) Name the cell labelled A. (1 mark)
24. Define the term pollution. (1 mark)
25. Name the causative against the following diseases. (2 marks)
i) Cholera
ii) Syphilis
26. State one adaptation of the following parts of a mammalian eye. (3 marks)
i) Fovea centralis
ii) Ciliary body
iii) Sclera
27. Give reasons why each of the steps is followed when preparing a cross section of a leaf for
examination under microscope. (2 marks)
(i) Cutting very thin sections.
(ii) Placing section water.

Page | 49
 KIENI EAST
231/2
PAPER 2
SECTION A:
1) The diagram below represents a type of respiration

a) State the type of respiration that was being investigated. (1 Mark)

b) i) Give a reason for your answer in (a) above. (1 Mark)
ii) State the observations made after six hours on the thermometer reading in flask A and B.
(2 Marks)
c) Account for the observations in Flask A and B.
Flask A (3 Marks)
Flask B (1 Mark)
2) A couple has three children, the mother had blood group A and the father had blood group B
while one of the children had blood group 0.
(a) i) What were the genotypes of the parents? (1mark)
Father
Mother
ii) What was the genotype of the child with blood group 0? (1mark)
(b) Work out using a punnet square the genotypes of the other children. (4 marks)
(c) Which child has blood group that allow him/her to receive blood from any member of the
family (1mark)
(d) State the percentage of children who can donate blood to all blood groups. (1mark)
3) Explain four milestones in the evolution of man that have made him the most dominant species
on earth. (8marks)
4) a) Write two differences between tropism and taxis (2mks)
b) A patient whose body temperature was 38oc was admitted in hospital in order to manage it.
The doctor diagnosed the problem to be associated with the brain. As a biologist which
part of the brain do you think was faulty? (1mk)
c) Study the diagram below and answer the questions that follow.

i) Name parts A B and C (3mks)

ii) On the diagram using an arrow, show the direction of nerve impulse (1mk)
iii) What’s the effect of auxins to the cells in the shoot tip? (1mk)
Page | 50
5 The equation below represents a metabolic process that occurs in the mammalian liver
Excess Amino Acids → organic compounds + urea
(a) Name the above process (1mk)
(b) What is the importance of the above process to the mammal? (2mks)
(c) What is the source of amino acids in the process (a) above (1mk)
(d) Study the diagram of the villus in the small intestine and answer the questions that follow.

i) Name the processes Q through which digested food in the ileum is absorbed (2mks)
ii) Name two substances transported in structure labelled L (2mks)
Section B:
Question 6 is compulsory; Answer either question 7 or 8

6.) In an experiment, lactic acid concentration was measured before, during and after vigorous
exercise to determine the effect of exercise on concentration of lactic acid in blood. Study the data
obtained and use it to answer the questions that follow.
Time(minutes) 0 10 20 25 30 40 50 60 70 80 90 100
lactic acid concentration 0.5 0.5 5 13 12 8 6 4 3 2 1 0.9
(arbitrary units)

a) In the grid provided, plot a graph of the concentration of lactic acid against time. (6mks)
b) From the graph,
i) Determine the period of exercise. (1mks)
ii) Explain your answer. (2mks)
c) i) What do you understand by oxygen debt? (1mks)
ii) Determine the time taken for oxygen debt that was incurred to be paid back.
Explain your answer (2mks)
d) Why does lactic acid level continue rising in blood even after exercise ceases? (2mks)
e) What is the fate of lactic acid in the body? (2mks)
f) State two effects of lactic acid in the tissues. (2mks)
g) Name two industrial processes that utilizes the reaction that lead to formation of lactic acid.
(2mks)
7. Discuss the adaptations of fruits and seeds to dispersal. (20 mks)
8. Explain the various ways in which a typical cell is adapted to its function (20 mks)

Page | 51
 KIENI EAST
231/3
PAPER 3
CONFIDENTIAL
Question 1
1. 4 test tubes per rack
2. Solution R – 1% starch solution
3. Solution T – Distilled water
4. Solution H – 1 Molar HCl (aq)
5. 15cm string
6. 8 cm long visking tubing
7. Iodine solution
8. 50 ml beaker
Question 2 and Question 3
1. Print photos on coloured printer.

KIENI EAST
231/3
PAPER 3
(PRACTICAL)
1 ¾ HOURS
TIME: 1 ¾ Hours
1. You are provided with Four Test-tubes label as A, B, C and D. You are required to prepare the
contents of test tube A, B, C and D as follows.
To test tube A add 2cm3 of solution R provided and test using the provided reagent.
To test tube B add 2cm3 of solution T provided and test using the provided reagent. (5 marks)
(a)
(b) To test tube C and D, prepare them as follows:
To test tube C add 2cm3 of R and 2cm3 of solution H provided boil it and allow it to stand for 5
minutes.
To test tube D add 2cm3 of R and 2cm3 of solution T boil and allow it to stand for 30 minutes.
For both C and D test using the provided reagents and tabulate your results below. (5 marks)
(c) To the provided visking tubing tie one end with the provided string and add solution R. Tie the
remaining end and immerse it in a solution of iodine solution in a beaker (50ml). After 2
minutes remove it from the beaker and observe.
i) What was your observation of the contents of the visking tubing at the end of experiment?
(1 mark)
ii) Account for your results in (i) above. (3 marks)
2. Study the kidney diagrams below:

a) i) Name the part labeled A in figure 1 (1mark)

ii) Name the process that takes place in the parts labeled V. (1 mark)
b) State two homeostatic functions of the organ in the diagram above (2marks)
Page | 52
c) Explain what will happen to the process of urine formation in absence of ADH. (3mark
d) Below are photographs labeled B and C of organs obtained from different animals. The organs
perform similar functions. Examine them and answer the questions that follow.

(i) Name the parts labeled B1, B2 and B3 in photographs B (3marks)

(ii) Identify the parts labeled K1, K2 and K3 in photograph C (3marks)
3. Study the diagrams set A1, set E1, set M1 and set B carefully and answer the questions below

a) State the conditions under which each set up was grown. (3mks)
Set A1
Set E1
Set B
b) i) Name the phenomenon exhibited by seedlings in set E1 (1mk)
ii) Give a reason why plants exhibit the phenomenon named in (b) (i) above (1mk)
c) i) Name the response exhibited by the seedlings in set B. (1mk)
ii) Explain how the response named in (c) (i) above occurred (2mks)
d) i) State the type of germination exhibited by seedlings in set A1 and set M1. (2mks)
Set A1
Set M1
ii) Give a reason for your answer in (d) (i) above (2mks)
Set A1
Set M1
iii) State the mode of dispersal in set A above when mature. (1 mk)
iv) Name the type of fruit formed by M1 on maturity. (1 mk)

Page | 53
 KIENI EAST
231/1
MARKING SCHEME
PAPER 1
1. Biology
2. (a) To reflect light through the condenser to the stage to illuminate the specimen.
(b)
− High power objective lens is long and can crush the lens and the slide on the stage.
− Image move in and out of focus too quickly therefore it’s difficult to precisely adjust the focus.
− Can destroy the specimen. (any correct)
3. (a) Forms a protective barrier to the stomach wall against corrosions by Hydrochloric acid and
protein digesting enzymes.
Lubricates the stomach lining. (2 mks)
(b) Young persons are growing hence rate of cells division is more than adults.
They are physically active than adults hence they require more energy. (2 mks)
4. (a) To increase surface area for attachment of respiratory enzymes hence increasing the rate of
respiration
(b) i) Stroma
ii) Bearing photosynthetic pigments or it contain chlorophyll molecules hence site for
light dependant
Reaction where light is trapped for photolysis.
Provides large surface area for maximum chlorophyll hence photolysis.
5. (a) Strong wind, high temperatures, low humidity
(b) Absence of leaves hence no surface area over water is lost, hence little or no transpiration.
(c) Habitat
A - Arid or dry or desert, semi -arid or hot environment.
Reason - low rate of water loss since xerophytes are adapted to reduce transpiration rate.
Habitat
B - Wet or moist or aquatic.
Reason: High rate of water loss. .
6. - They are numerous forming a dense network close to every cell for efficient exchange of
substances.
- Have thin walls to provide the least distance for diffusing molecules.
- Have a narrow lumen to maintain high pressure for ultra-filtration.
7. (a) Respiration / aerobic respiration.
(b) Absorbs carbon (v) oxide from the atmosphere.
(c) L - Remained clear; no white - PH formed because carbon (iv) from the atmosphere has
been absorbed by potassium hydroxide.
N - Lime water forms white ppt; where carbon (iv) oxide was given out by cockroaches
during respiration
8. Bean plant - Dicotyledonae
Reason: leaves have network veins; two cotyledons; tap root system; xylem star shaped with
phloem in between the arms, has cambium hence secondary growth.
Bat - Mammalian
Reason - have sweat glands, 3 ear ossicle; presence of fur; mammary glands, give birth to young
ones.
9. i) Protandry - Male reproduction organ / anthers / stamens mature earlier than female
reproduction organ /carpels / stigma / pistils / gynoecium in a flower
ii) Self - sterility - pollen grains are sterile to stigma of the same flower in the plant.
10. a) Passage of ova / site for fertilization.
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 b) Storage of sperms.
c) Holds the testis / protects the testis / provide slightly lower temperatures for
spermatogenesis since its
located outside abdominal cavity.
11. a) Failure of homologous chromosomes to segregate during meiosis / anaphase/ meiosis or
Failure of sister chromatid to separate during mesons / anaphae ll / meiosis ll leading to
cell having an extra set of chromosomes.
b) i) Down’s syndrome (or mongolism), Tuner’s syndrome, klinetelter’s syndrome.
ii) Albinism, sickle cell anaemia, Haemophilia, colour blindness chondrodytrophic,
dwarfism / achondroplasia.
12. a) Sensory nerve cell neurone.
b) - Cell body is located off the axon or outside the CNS.
- Have both axon and dendron that are long.
c) Schwann cell.
d) Makes contact with central nervous system (CNS) or receptor organs thus transmitting
impulses.
13. a) Homologous Analogous
- Structures from same empyemic organ. Structure from different embymis origin.
- Have different functions Same functions.
b) It is split, drift and separation of the present continent; from a common land mass
isolating animals; which have evolved in different ways adapting; differently;
14. a) Features of vertebra: (a) Centrum (ii) Neural canal (iii) Transverse process.
15. a) A - Epigeal;
B - Hypogeal;
b) Used in oxidation of food to release energy;
16. Ecological Niche - Position occupied by an organism in a habitats and its role interns of
nutrition.
Biosphere - part of earth that support life.
Population - member of same species in a particular habitat a particular time.
17.
− For easier identification of organisms.
− Arrangement of information in orderly manner.
− To understand evolutionary history.
− Grouping of organisms according similarities and differences.
18. They naturally interbreed to produce a fertile offspring (viable)
19. (a) Concentration gradient.
(b) The higher the gradient the higher the rate of diffusion lower the gradient the lower the rate
of diffusion.
20. Temperature affects the ergometric; which affect energy production required in active transport.
21. Less insulin secretion of blood; less glucose is converted into glycogen; hence more sugar in the
blood
for ultra filtration in kidney; (OWTTE)
22. Rubber - types
Papain - meat tenderizer
Quinine - used ad malaria drug
23. (a)
− Vascurized for effect transport.
− Thin epithelium to enhance diffusion of gases.
− Moist surface to dissolve diffusion; gases
b) Red blood cell ; (Erythrocyte)
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24. Addition / emission of scroslances to environment in such quantities whose affect are harmful to
organisms.
25. Chorela - vibrio cholerae
Syphilis - Traponema pallidum rej wrong spelling not underlined (observe rules/ classification.
26. Fovae centralis - more cones for bright vision
ciliary body - Have ciliary muscles which alters the tension of suspensory ligament.
Sclera - Tough connective tissue to support and protect the other part of the eye.
27. (a) For light to pass through
(b) Maintain turgidity (cell)
```

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 KIENI EAST
231/2
PAPER 2
1.
a) State the type of respiration that was being investigated. (1 Mark)
Anaerobic respiration;
b) i) Give a reason for your answer in (a) above. (1 Mark)
Presence of yeast to produce enzyme / presence of oil layer to prevent entry of air /
Oxygen.;
ii) State the observations made after six hours on the thermometer reading in flask A and B.
(2 Marks)
Flask A: Reading in Thermometer was higher;.
Flask B: No change in Thermometer reading ;
c) Account for the observations in Flask A and B.
Flask A (3 Marks)
Flask A: Glucose; solution was acted upon by the enzyme (zymase) produced by yeast ;thus
breakdown to form carbon (iv) oxide alcohol and heat / energy; causing a rise in temperature.
Flask B (1 Mark)
Flask B: Yeast cells are killed by boiling thus no reaction occurs;.
Acc: Enzymes are denatured by high temperature above optimum/yeast cells are killed by high
temperature above optimum;.

2. A couple has three children, the mother had blood group A and the father had blood group B
while one of the children had blood group 0.
(a) i) What were the genotypes of the parents? (1mark)
Father
Father - BO, (two correct to score)
Mother
Mother - AO;
ii) What was the genotype of the child with blood group 0? (1mark)
OO;
b) Work out using a punnet square the genotypes of the other children. (4 marks)
♂ ♀
Parental genotype BO x AO ;
Gametes B O A 0 ;

♂ B O
♀

A AB AO
O BO OO
Genotype of the other children AB, BO, AO; OO
(c) Which child has blood group that allow him/her to receive blood from any member of the
family? (1mark)
AB;
(d) State the percentage of children who can donate blood to all blood groups (1mark)
OO = ¼ X 100 = 25%

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3. Explain four milestones in the evolution of man that have made him the most dominant species
on earth. (8marks)
Man has a larger brain giving him more intellectual capacity and this has enabled him to exploit
the environment fully;
Ability to speak/use language to communicate clearly with his fellow men;
Bipedal locomotion, upright posture that frees the hands and rises them to manipulate the
environment and carry objects;
Aprehensile/grasping hand that enables him to handle things with a high degree of precision;
Forward facing eyes which gives him a three-dimensional view for the purpose of judging
distances and have wider angle of view;
4. (i) Write two differences between tropism and taxis (2mks)
Tropism taxis
It’s a growth curvature it’s a locomotory response
It’s a slow response it’s a rapid response
Controlled by hormones controlled by some organelles

(b) A patient whose body temperature was 38oc was admitted in hospital in order to manage it. The
doctor diagnosed the problem to be associated with the brain. As a biologist which part of the
brain was faulty? (1mk)
The hypothalamus
(c) Study the diagram below and answer the questions that follow.
(i) Label parts A B and C (3mks)
A – Axon
B – cell body/canton
C – Node of Ranvier
(ii) On the diagram using an arrow, show the direction of nerve impulse (1mk)
(iii) What’s the effect of auxins to the cells in the shoot tip?
It stimulates cell division
It stimulates cell elongation
5 The equation below represents a metabolic process that occurs in the mammalian liver
Excess Amino Acids → organic compounds + urea
(a) Name the above process (1mk)
Deamination
(b) What is the importance of the above process to the mammal? (2mks)
− To get rid of excess amino acids since they cannot be stored
− Some amino acids may be converted into glucose for respiration
(c) What is the source of amino acids in the process (a) above (1mk)
Proteins in the diet
(d) Study the diagram of the villus in the small intestine and answer the questions that follow.
(i) Name the processes Q through which digested food in the ileum is absorbed (2mks)
− Active transport
− Diffusion
Rej osmosis
(ii) Name two substances transported in structure labelled L (2mks)
Fatty acids
Glycerol
6.
a) In the grid provided, plot a graph of the concentration of lactic acid against time. (6mks)
b) From the graph,
i) Determine the period of exercise. (1mks)
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 10-25 minutes
ii) Explain your answer. (2mks)
Period of rapid increase in lactic acid concentration
c) i) What do you understand by oxygen debt? (1mks)
Oxygen required to get rid of lactic acid that accumulates in the body tissues when oxygen
supply is less than its demand
ii) Determine the time taken for oxygen debt that was incurred to be paid back. Explain your
answer (2mks)
75 minutes from 25th and 100th
Time that lactic acid took to decrease from the highest to normal level
d) Why does lactic acid level continue rising in blood even after exercise ceases? (2mks)
Continue diffusing from the muscle tissue where it was produced to blood stream.
e) What is the fate of lactic acid in the body? (2mks)
Oxidized to carbon (IV) oxide, water and energy when oxygen is made available.
Taken to the liver and e converted to glycogen and stored
f) State two effects of lactic acid in the tissues. (2mks)
Fatigue
Muscle crumps
g) Name two industrial processes that utilizes the reaction that lead to formation of lactic acid
Bread baking
Brewing
Manufacture of organic acid
Processing of dairy products
7. Discuss the adaptations of fruits and seeds to dispersal. (20 Marks)
Animal dispersal;
− Presence of hooks on ovary walls / calyx; e.g. in Biden’s Pilosa for attachment on animal’s hair
/ for or clothes of human beings; Succulent fruits; brightly coloured epicarp; and scented fruits;
that attract animals; Some fruits are eaten together with seeds. The seeds have coats which are
resistant to digestive enzymes; hence pass through the gut undigested ;and passed out through
faeces far from the parent plant e.g. passion, tomato, guava, lantana.
Water dispersal;
− Fruits and seeds dispersed by water are light; hence float on water;. Their seed coats are
waterproof ;preventing them from soaking in water and sinking.
− In some fruits e.g. coconut mesocarp is fibrous and spongy. Air is trapped making the fruit light.
Some water plants e.g. water lily have seeds whose coats trap out bubbles. The bubbles make
the seeds float on water and can be carried away from the parent plant. The pericarp and the
testa are water proof hence seeds remain afloat without soaking and sinking.
Wind dispersal
− Fruits and seeds should be light and small to be carried by air currents.
− Some fruits and seeds have hairy and feather like projections that increase the surface area for
them to be carried away by air currents and dropped far from the parent plant e.g. sonchusspp
and cotton.
− Some fruits and seeds have wing-like structures e.g. the surface area so that they are easily
carried away by air currents.
Censor mechanism
− Some fruits are capsule-shaped. Some have pores at the top e.g. tobacco split along lines of
weakness. The capsule is attached to a long stalk, hence swayed away by the winds, the seeds
are released and scattered away from the parent plant.
Self-dispersal

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− This occurs in legumes. When the pod dries up, the seeds break off from the parent plant. The
pod opens along the lines of weakness throwing seeds away from the plant e.g. beans, castor oil.
(Max 20 Mks)
8. Explain the various ways in which a typical cell is adapted to its function
− Cell membrane; with pores for semi-permeability; enclose the other organelles for Gaseous
exchange;
− Has cytoplasm; that contain sugars and salts; For maintaining its osmotic pressure;
Is a fluid medium; for chemical reactions;
− Has nucleus; that contain chromosomes; that contain hereditary material; and control all the
activities of the cell.Has pores for passage of RNA molecule;
− It has ribosomes; which are sites for protein synthesis;
− It has Golgi apparatus/bodies; for production of lysosomes;
Secretion of enzymes/glycoproteins;
Process/package; and transport
Glycoproteins/lipoprotein/secretions of packaged materials eg glycoproteins;
− Has lysosomes; that store (hydrolytic) enzymes;
That destroy worn out organelles/pathogens;
Lytic enzymes digest food materials
− It has smooth endoplasmic reticulum; that synthesizes; and transport lipids/steroids
− It has Rough endoplasmic reticulum; that transport proteins;
Provides the sites for attachment of ribosomes.
− It has nucleolus; that produces hysosomes;produces RNA material
− It has centrioles; it forms cilia and flagella;forms spindle fibres during cell division;
− It has vacuoles; for digestion of food; to store salts and sugars to control osmotic pressure;
contractile vacuole in amoeba are used to excrete excess water;in animals its used in food
digestion;
− Green plant cells have chloroplasts; that form site for photosynthesis;
− Plant cell have cell wall; to provide cell with definite shape;
- To allow substances to pass through
- To prevent the cell from bursting when its furgid;

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 KIENI EAST
Paper 3
MARKING SCHEME
1. You are provided with Four Test-tubes label as A, B, C and D. You are required to prepare the
contents of test tube A, B, C and D as follows.
To test tube A add 2cm3 of solution R provided and test using the provided reagent.
To test tube B add 2cm3 of solution T provided and test using the provided reagent.(5 marks)
(a)
Test tube Procedure Observation Conclusion
A Add 2cm3of R and 2 drops of iodine solution Blue-black; Starch present;
B Add 2cm3of R and 2 drops of iodine solution Yellow-brown; Starch absent
(b) To test tube C and D, prepare them as follows:
To test tube C add 2cm3 of R and 2cm3 of solution H provided boil it and allow it to stand for 5
minutes.
To test tube D add 2cm3 of R and 2cm3 of solution T boil and allow it to stand for 30 minutes.
For both C and D test using the provided reagents and tabulate your results below. (5 marks)

Test tube Procedure Observation Conclusion

3
C Add 2cm of treated R with H, 2 Remains yellow- brown Starch absent
drops of iodine solution
D Add 2cm3 of treated R with T 2 Remains yellow-brown Starch absent
drops of iodine solution
(c) To the provided visking tubing tie one end with the provided string and add solution R. Tie the
remaining end and immerse it in a solution of iodine solution in a beaker (50ml). After 2
minutes remove it from the beaker and observe.
i) What was your observation of the contents of the visking tubing at the end of experiment?
Contents turns blue-black
ii) Account for your results in (i) above. (3 marks)
Iodine molecules are relatively small and diffused; into the visking tubing reacting with the
contents to give blue-black colouration; shows presence of starch in R;
2. a) i) Renal vein;
ii) Ultra filtration/pressure filtration;
b) Osmoregulation;
Regulation of PH;
c) The distal convoluted tubules and collecting duct wilt be less permeable to water; therefore less
reabsorption of water; leading to production of large volume of urine that is dilute;
3. a)
Set 1 – normal conditions
Set E1 – in the dark
Set B – unidirectional light 3mks
b) i) Etiolation; 1mk
ii) To reach light for photosynthesis; 1mk
c) i) Positive phototropism; 1mk
ii) Auxins migrate to the darker side causing faster growth/elongation on this side; resulting in
curvature of the shoot towards the source of light; 2mks
d) i) Set A1 – Epigeal; Set M1 – hypogeal;
(ii) Set A1 – cotyledons brought above the ground; 1mk
Set M1 – cotyledons remain below the earth’s surface/ underground; 1mk

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 KIRINYAGA WEST SCHOOL BASED EXAMINATION
231/1 (THEORY)
BIOLOGY
PAPER 1
TIME: 2 HOURS
1. Name the organelle that performs each of the following function (2 marks)
a) Destroy worn out organelles
b) Tissue respiration
2. Which physiological process is responsible for?
a). Opening of stomata to allow gaseous exchange. (1 mark)
b) Acceleration of absorption of sugar /glucose and some salts by the kidney of mammals.
3. a) What is cell specialization? (1 mark)
b) State how each of the cell listed below is specialized to carry out its function
i). Palisade cell. (1 mark)
ii) A sperm cell (1 mark)
4. (a). Explain why primary productivity decreases with depth in aquatic environment. (2 marks)
(b) Removal of predators for a herbivore may in the long run lead to decrease in its population.
Suggest reasons to account for this observation. (3 marks)
5. On a certain cold night, a man lit a jiko to warm the house, closed all the windows and went to sleep.
The following morning, he was found dead. What could have led to his death? (3 marks)
6. Elodea is a green water plant. An experiment was set up as shown in the diagram below.
In one experiment set up light was provided and in the other light was absent.

a) .In the figure above was this set –up placed in the light or in darkness? (1 mark)
ii). Name the gas collected in the test tube .How is it tested? (2 marks)
iii) Why was one experimental set- up placed in darkness? (1 mark)
b) State two factor that affect the rate of photosynthesis. (2 marks)
7. What role does the following play in reproduction?
(a). Acrosome (1 mark)
(b). Luteininsing hormone (1 mark)
8. Below is a diagram of a bacterium.

(a) Identify the kingdom to which the organism belongs. (1 mark)

(b) State two features shown on the diagram that are characteristics of the kingdom. (2 marks)
9. Part of the one strand of DNA molecule was found to have the following base sequence.
A -- C--T--G--A--C--T--G
(a) What is the sequence on the M-RNA strand copied from this DNA portion? (1 mark)
b) State three roles of DNA molecule. (3 marks)
10. The diagram below represents a neurone.

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(a) Identify, with a reason, the type of neuron above. (2 marks)
(b). Name the part labeled M, Q and Z. (3 marks)
(c) State the function of this neurone. (1 mark)
(d) Using an arrow, show the direction of impulse on the diagram. (1 mark)
11. The chat below is a summary of the blood clotting mechanism in man.

Prothrombin X

Y Thromboplastin

Thrombin

Fibrinogen Z

i). Name the blood cells represented by X (1 mark)

ii). Metal ion represented by Y (1 mark)
iii) The end – product of the mechanism represented by Z. (1 mark)
12. The diagram below represents a transverse section of a plant organ.

(a). Name the plant organ from which the section was obtained. (1 mark)
(b). i). Name the class to which the plant organ belongs. (1 mark)
ii). Give a reason for your answer in (b) (i) above (1 mark)
(c) Name the part labelled X. (1 mark)
13. An individual is of blood group B positive.
(a). Name the antigens in the individual’s blood. (2marks)
(b). Give the reason why the individual cannot receive blood from a blood group A donor.
(c) Explain the role of calcium in blood clotting. (2 marks)
14. (a). Define the following terms
(i) Entomology (1 mark)
(ii) Genetics (1 mark)
(b) Rewrite the following scientific name of the wolf, CANIS LUPUS in accordance to binomial
nomenclature rules. (1 mark)
15.
(a). Explain why only fine adjustment knob should be used when focusing a specimen using the
high power objective lens of the light microscope. (2 marks)
(b) An animal cell was viewed under a light microscope using objectives lens of x75 and eyepiece lens of
x10. Determine the total magnification of the image. (2 marks)

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16. Study the homeostatic scheme below and answer the question that follows.
Further excess
D

Excess Less hormone

A released

Normal Concentration Normal concentration

of Sodium ions of Sodium ions

Deficiency Release of hormone A

Further deficiency
a). Identify the hormone labeled A. (1 mark)
b). Name the site of action of hormone A. (1 mark)
c). Identify the feedback mechanism labeled.
i) C (1 mark)
ii) D (1 mark)
17. The table below shows stomata distribution on leaves A and B and their surface area. Use the
information to answer the question that follow.
Leaf surface A B
Number of stomata Upper surface 20 5
Lower surface 0 15
Surface area 25 cm square 18 cm square
a). Identify with a reason, the habitat of the plants from which the leave were obtained.
i) Leaf A (2 marks
ii) Leaf B (2 marks)
18. Which type of joint is found at the articulations of?
a) Pelvic girdle and femur (1 mark)
b). Humerus and ulna (1 mark)
19. a). Name the bone that allows the head to
i) Nod (1 mark)
ii) Turn side ways (1 mark)
20. State two adaptations of xylem vessels to their function. (2 marks)
21. In the set –up shown below, bean seeds soaked in water for 12 hours were placed in large air tight
glass jars.

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 Jar A Jar B
a) What was the air of the experiment? (1 mark)
b). What would be the expected observation after 5 days. (2 marks)
c). Suggested the expected changes in the composition of gases in jar B on the fifth day.
(2 marks)
d). Give reasons for your answer in (c) above. (2 marks)
22. a). State why Lamark’s theory of evolution is not accepted today. (1 mark)
b). Sate two evidences of organic evolution. (2 marks)

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 KIRINYAGA WEST SCHOOL BASED EXAMINATIONS
231/2
PAPER 2
2 HOURS
SECTION A
1. a) Name the laboratory apparatus used for the following (2mks)
i). Catching small flying insect
ii). Sucking small animals from rock surface or barks of trees.
b) State the function of the following cell organelles
i) Nucleolus (1mk)
ii) Lysosomes (1mk)
iii) Ribosomes (1mk)
c) State three differences between a plant cell and an animal cell (3 mks)
2. The diagram, below represent the nitrogen cycle

Nitrogen
in Air

a) Letter A and D represent biological processes in plants

i). Name the structure in which the processes A and D take place (2 mks)
ii). Name the compound represent by B (1mk)
iii). What is nitrogen fixation? (1 mk)
b) The food chain below represents a feeding relationship in an ecosystem
Planktonic tilapia Nile perch
Algae (1000) (300) (100)
i). What is a food chain? (1 mk)
ii). Name the trophic level occupied by Tilapia in this habitat (1mk)
iii) Draw a pyramid of numbers for the above food chain. (1mk)
c). Account for the trend observed in the pyramid (1mk)
3. The figure below illustrate a response in plants.

a) State the type of response illustrated (1mk)

b). Explain how the response occurs (4mks)
c). Sate two importance of phototactic in termites (2mks)

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d). State hormone used in agriculture that breaks seed dormancy. (1mk)
4. The diagram below represents a stage in cell.

a) i) Identify the stage of cell division (1mk)

ii) Give two reasons to support your answer. (2mks)
b). Give the similarities between mitosis and meiosis. (2mks)
c) State the significance of sexual reproduction (3mks)
5. A common species of rat has individuals with white, black or grey coats. During a study a rat with
white coat was crossed with a rat with grey coat. Both parent were pure lines. All the offspring in F1
generation had grey coat. Using letter B to represent the gene for black coat and W for white coat
answer the following question.
a) Work the phenotypic ratio of the F2 generation (3mks)
b). Give a genetic explanation for the appearances of rats with grey colour. (1mk)
c). State the significance of the test cross in the study of genetics (1mk)
d). State two importance of crossing over in meiosis. (2mks)
e). Name one example of characteristics in man that is transmitted by multiple alleles. (1mk)
SECTION B (40 Marks)
Answer question 6 (compulsory) and either question 7 and or 8 in the space provided after question 8
6. An experiment was carried out to investigate the effect of pH on the rate of reaction catalysed with
an enzyme. The result are as shown in the table below

PH Rate of reaction in mg of production per unit time

Enzyme R Enzyme T
0.5 0.2 0.0
1.5 1.5 0.0
2.0 2.3 0.0
3.0 3.4 0.0
4.0 2.2 0.8
5.5 0.1 1.6
7.0 0.0 2.6
8.0 0.0 3.2
9.0 0.0 1.2
a). On the grid provided draw a graph of rate of reaction against pH. (7mks)
b) i). What is the rate of reaction of the two enzymes at pH of 5.0? (2mks)
ii). What is the optimum pH of each enzyme? (2mks)
iii). Give a reason for your answer in b. (ii) above. (1mk)
c) Suggest the identity of enzyme R and T and name the region of the alimentary canal where they are
likely to be found . (4mk)
d). Other than pH name two factor which may alter the rate of enzymes controlled reactions
e) Explain the role of bile juice in digestion. (2mk)
7. a) Explain the role to the following hormone in growth and development of plants
i) Auxins (4 mks)
ii) Gibberellins (4mks)
b). Explain the condition necessary for germination of seeds. (12mks)
8. a) Explain how plants can eliminate metabolic waste products (8mks)
b) Explain why plants have less specialized excretory organ as compared to animals. (5 mks)
c) How is the kidney adapted to perform its function? (7mks)

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 KIRINYAGA WEST SCHOOL BASED EXAMINATION
231/3
PRACTICALS
CONFIDENTIAL
Each candidate should be provided with the following.
1. Solution L (milk) 15m/s per student in a beaker
2. Filter paper (1)
3. funnel
4. 100ml beaker (2)
5. 4 test tubes in a test tube rack
6. Petri dish
7. Spatula
8. Hibiscus twig with a flower (Specimen 3) and flower bud with labeled parts
i) Flower bud as U
ii) Staminal tube as W
iii) Stigma as V
9. Bouganvillea twig with a flower (Specimen 1). Label bract as P
10. Tradescantia twig with flower (Specimen 2). Label flower as X

Access to
• Iodine solution
• Copper (II) Sulphate (1%)
• Sodium hydroxide (5%)
• Source of heat
• HCl (aq) solution (0.5m)

KIRINYAGA WEST SCHOOL BASED EXAMINATION

231/3 (PRACTIAL)
PAPER 3
TIME: I HOUR 45 MINUTES
1. You are provided with solution L and laboratory reagents. Use it to carry out experiments as follows.
i) Take the filter paper and carefully fold it twice through the middle. Open it up to make a funnel. Put
it in a plastic funnel. Place the set up in 100ml beaker
ii) Take 15ml of solution L add 5 drops of dilute hydrochloric acid (HCl)
a). Record your observation. (1 mark)
b). Where in the body is HCl found and what is its importance in the body . (2mks)
iii) Using the set up, filter solution L into 100ml beaker. Remove from the filter paper all the material on
it and place them in Petri dish using the spatula. Dry the filter paper over flame care being taken not
to burn it
a). Record your observation. (1 mk)

b). What conclusion do you make on the observation? (1 mk)

c). What name is given to this test? (1mk)

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iv) Use the provided reagents to carry out food test on the filtrate and residue by filling in the table
below.
FILTRATE (4mks)
Food being test Procedure Observation Conclusion
Starch
Protein
RESIDUE (4mks)
Food being tested procedure observation conclusion
Starch
Proteins

2. The photograph below represents structure of certain animal species. Study them and answer the
question that follows

a). Identify the type of structure represented by photographs A and B. (2 mks)

b) What is the specific function of the three structure shown in the photograph A
c) Differentiate between the structures you have identified (named) in (a) above . (4mks)
d) Name the type of evolution exhibited by photograph A and B. (2mks)
e). Using Darwin theory of evolution explain how the whales flipper E would have
evolved. (2 mks)
f) Sate two limitations of fossil records as an evidence of evolution. (2mks)
3. You are provided with specimen labeled 1,2, and 3 uses them to answer question that follow.
a) i) State the division and sub –division which the specimens belong to (2mk)
ii). Give a reason for your answer in a) (i) above. (1 mk)
b) Identify the class that specimen 2 belong to and give a reason for your answer. (2mks)
c). With a reason suggest the agent of pollination for the three specimen. (2mks)
d) Identify the part labeled V, W and P, (3 mks)
e) i). Identify the developmental stage represented by U (1 mk)
ii). State the significance of part labeled U (1mk)
iii). Describe the floral parts of specimen 2 (1 mk)

Page | 69
 KIRINYAG WEST SCHOOL BASED EXAMINATION
PAPER 1
231/1
MARKING SCHEME
1. (a) Lysosome ; (1mk)
(b). Mitochondrion ; (1 mark)
2. (a) Osmosis; (1 mark)
(b) Active transport ; (1 mark)
3. (a). Structural modification of the cell to perform specific function; (1 mark)
(b)i). Found just beneath upper epidermis and closely packed so as to trap maximum sunlight ;
Have numerous chloroplasts contusing chlorophyll, which trap light energy for photosynthesis.
ii) . Has a tail to propel it towards the ovum.
Have many mitochondria to provide energy for propulsion.
Has an acrosome that reassess enzymes to digest cell membrane mark any I (max 1 mks)
4. a). With depth in aquatic environment light intensity decreases: hence less or no photosynthesis
/less or no producers. ; (2mks)
b). Population of herbivores increase due to the absence of predators) leading to overgrazing, It
results to decrease in vegetation, leading to starvation, and death of some herbivores (hence
decrease in their population) ; max (3 mks)
5. Poor ventilation leads to the Jiko producing carbon (II) oxide; which combine with hemoglobin to
form carboxyhaemoglobin, ; which does not dissociate hence suffocated from lack of oxygen, ; in
his tissues (max (3 mks)
6. a.)i) - In the light (1 Mk)
ii) Oxygen; relights a glowing splint (2 mks)
iii) Control experiment (1 Mk)
b). Light intensity
Carbon (IV) oxide concentration
Temperature
Mark any 2 marks ( max 2 mks )
7. a) Contains lytic enzymes used to digest cells of the ovum for sperm penetration during
fertilization
b) Trigger ovulation ;
Triggers release of progesterone hormone that maintains pregnancy, mark any (1 mk)
8. a) Monera (1 mk) M must be in capital
b) Unicellular
Prokaryotic /no definite nucleus
Presence of flagella; Rej. Flagellum
Few organelles
Mark the first two (2 mks)
9. a) U-C-T-G-U-C-T-G (1 mk)
b) Store genetic information in a coded form.
Enables the transfer of genetic information unchanged to daughter cells through replication
Translates the genetic information into characteristics of an organism through protein synthesis.
10. a) sensory neurone
Cell body is situated off the axon and outside the CNS
Receptor dendrites located in the sense organ while terminal dendrites are located in the
CNS mark any (1mk)
b) M - Myelin Sheath
Q - Cell body
Z - Schwannn cell ( 3 mks )
c) Transmit nerve impulses from the sense organ to the CNS (1 Mk)
d) The arrow must be shown on the diagram (1 Mk)

Page | 70
11. i) X-platelets (1 mk)
ii) Y-calcium ions (1mk)_
iii) Z-Fibrin (clot) (1mk)
12. a) stem (1mk)
b) i) Monocotyledonae (1mk)
ii) Vascular bundles are scattered
Absence of pith/cambium mark any (1 mk)
c) Epidermis
13. a) Antigen B, and Rhesus factor /Rhesus antigen /Antigen D (2 mark)
b). Recipient plasma antibody A which can corresponds to antigen A which can cause
agglutination of red blood cells (2mk)
14. a) study of insect; (1 mk)
ii) Study of inheritance and variation; (1mk)
b) Canis Lupus ; (1 mk)
15. a) the distance /space for manipulation on the stage is limited; to avoid crushing the slide
/specimen
b) Total magnification=eye piece (lens) x objective (lens) x10 x 75 = x750 (2 mks)
Formula- (1mk)
Working (1 mk)
16. a) A-Aldosterone (hormone) (1 Mk)
b) Distal convoluted tubule and collecting duct /tubule (1 Mk)
c) i) C-Negative feedback
ii) D-positive feedback (2mks)
17. a) leaf A
Habitat Aquatic (1 mk)
Reason; -stomata found on the upper surface only
Leaf offers a large surface area. Mark any 1 (1 mk)
ii) Leaf B
Habitat; Desert /Arid /Semi-arid (1 mk)
Reason, -Few stomata on the upper leaf surface
Many stomata on lower leaf surface
Mark any 1 (1 mk)
18. a) Ball and socket joint (1 mk)
b) Hinge joint (1 mk)
19. a) Atlas (1 mk) b) Axis (1 mk)
20. They are lignified or thickened to prevent collapsing
Having long and narrow lumen to facilitate capillarity
Made up of dead cells to ensure passage of water (mark 1st two) (2mks)
21. a) to show that oxygen is necessary for germination (1mk)
b) Germination occurs in jar B, but not in jar A (2 mks)
c). Concentration of oxygen decreases while concentration of carbon (IV) oxide increase (2 mks)
d). Germinating seeds respire using oxygen with release of carbon (IV) oxide (2 mks)
22. a) Acquired characteristics are not inherited (1 mk)
b) Fossil records; Geographical distribution; Comparative embryology; Comparative anatomy;
Cell biology; (any 2)

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 KIRINYAGA WEST SCHOOL BASED EXAMINATIONS
231/2
PAPER 2
MARKING SCHEME
1. a). i) sweep net
b) Pooter
b) i) Synthesis of ribosomes
ii) Destroy worn out cell organelles
iii) Synthesis of protein
c) Plant cell Animal cell
Has cell wall; no cell wall;
Store carbohydrates in form of starch; stores carbohydrates in form of glycogen;
Regular shape ; irregular shape;
Has a peripheral placed nucleus; has a centrally placed nucleus;
Large central vacuole; small vacuoles scattered in the cytoplasm;
Some have chloroplast; no chloroplasts ;

2. a). i) A Root nodules

D Root hair
ii) Nitrites
iii) It is the conversion of free nitrogen in air into nitrates
b). i) it is the linear flow of energy through differed trophic level in an ecosystem
ii) Primary consumers
iii) Pyramid of numbers to be drawn to scale
Scale 1 cm rep. 100 organisms.
Nile Perch (100)
Tilapia (300)

Planktonic algae (1000)

5 4 3 2 1 0 1 2 3 4 5
c) There is gradual decrease in number due to energy loss through respiration, defecation, and urination
3. a) Haptotropism /thigmotropism (1 mk)
b) Auxin is produced at shoot tip;
Auxin move by diffusion through phloem to zone of cell elongation
Auxin migrate away from contact /accumulates on the side away from contact
High concentration of auxin hormone promote faster cell elongation /expansion /growth
than the side in contact with object /lower concentration of auxin on the side in contact has
a lower cell elongation /growth (4 mks)
c) to avoid dehydration (2mks)
To escape predators
d) Gibberelins (1mk)
Cytokinnins
Ethylene
4. a) Metaphase I
ii) Chromosomes align themselves at the equator
Chromosomes are all non –homologus
b) Both take part in cell
Both involve / /cell multiplication
c). Genetic Variation
- Greater adaptable to environment by offspring
- Few bad or good traits inherited /retained

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- Greater amount of dispersal is possible
- May result in stronger offspring
5. a)

Genotypes BW x BW

Gamees B W B W

Fusion

F1 generation BB BW BW WW 
Black Grey coat White coat
Phenotypic ratio 1black coat; 2 grey coats; 1 white coat 
b) Incomplete /Partial dominance
c) . To establish the unknown genotypes of an organism
d) . Result in new gene combination /recombination
- Leads to variation /hybrid vigour
e) The human blood group/ ABO blood group system.
6.a) Graph of rate of reaction against pH of the enzymes

Scale =1
Labeling axes =1
Plotting =2
Smooth curve =2
Identify of curves =1
07 7mmk
b. i) At pH 5.0 Enzymes R =0.6 mg/unit time
Enzyme T =1.3 mg /unit time
ii) Optimum pH Enzyme R =3.0
Enzyme T =8.0
iii) Product formation /reaction is maximum at these Ph
c) Enzyme R ;Identity; Rennin /pepsin
Region; stomach

Page | 73
 Enzyme T identity: Ptyalin/ Salivary amylase /trypins
Region; Mouth/duodenum/ileum (4 mks)
d) Temperature; enzyme concentration, inhibitors; substrate concentration (2mks)
e) Contain bile salt; which neutralizes acidic chyme and emulsifies fats. (2 mks)
7. a). (i) Auxins
Promote cell / elongation
Promote fruit formation/parthenocarpy
Promote formation of abscission layer /brings leaf fall
Cause apical dominance
Promote growth for adventitious root and lateral branches Any four (4 mks)
(ii) Giberllins/giberrelic acid
Promote cell elongation
Parthenocarpy /initiate formation of fruits
Formation of side branch /end dormancy in buds
Inhibit growth of adventitious roots
Activates enzymes during germination
Affects leaf expansion and shape (any 4)
b). i) Water (moisture)
Activate germination enzyme/breaks seed dormancy
Provides medium for enzyme to act
Soften seed coat, which burst open to allow emergency of radical and plumule
Hydrolysis of food during germination
ii) Oxygen
Oxidation of food during respiration to provide energy for germination and formation of new tissues
iii). Optimum temperature
Suitable for action of germination enzymes which hydrolyse stored food.
Low temperature below 00 inactivate germination enzyme slowing down germination rate
High temperature above 400 denatures germination enzymes stooping germination
iv) Enzymes
Break down food by oxidation
v) Viability
Refers to percentage change that seed will germinate when planted
Seed stored for long time lose their viability
vi) Hormones
These stimulate certain metabolic pathways in the germination process
Every condition identified 1mk x6 = 6mks
Every explanation identify 1mk x6 = 6mks=12 mks
8.a) Diffusion; Gases e.g. carbon (iv) oxide and oxygen are removed through the stomata and lenticels;
Storage ; Non-toxic waste products are stored in the leaves, fruits, bark, flower e.g. Tannins and
resin, alkaloids, quinine, caffeine;
Exudation; Resins and tannins are exuded through the bark; (8 mks)
a) Leaf fall/organ fall; stored wastes are eliminated when leaves or fruits fall;
b) Waste do not accumulate in excess since plants only manufacture what they require
Plant is able to recycle waste./ Carbon IV oxide for photosynthesis, oxygen for respiration and
ammonia for protein synthesis
Metabolism in plant is mainly based on carbohydrates whose wastes are less toxic
Rate of metabolism in plant is slower than in animals
Plant keeps on growing throughout their lives and use nitrogenous waste products for protein
synthesis
Toxic waste are converted to non –toxic waste and stored in the barks e.g. Tannins
Any 5 @1mk each) (max 5mks)
c). Has collecting tubule/ Collecting duct, to transport the urine to the pelvis.

Page | 74
The kidney has renal artery to deliver blood from the dorsal aorta
Has renal vein to transport blood to the inferior vena cava
The kidney has ureter to transport the urine to the urinary bladder; the nephron has the following
adaptations.
The glomerulus’s has pores, through which blood is filtered off.
The Bowman’s capsule is funnel like to lead the glomerular filterate into the proximal convoluted
tubule
The promixal convoluted tubule is highly coiled, to slow down the flow of filtrate hence allow
enough time for selective reabsorption;
The nephron is narrow, to increase the contact between the filtrate and the walls of the tubule so as to
maximize selective reabsorption;
The proximal convoluted tubule has numerous mitochondria to produce ATP energy for active
reabsorption of glucose’
The flow of blood and that of the filtrate are counter current to maintain a high concentration
gradient for the materials being absorbed;
Has collecting tubule/collection duct, to transport the urine to the pelvis (any 7 @1mk)
(max 7 mks)

Page | 75
 KIRINYAGA WEST SCHOOL BASED EXAMINATION
231/3
PRACTICAL
MARKING SCHEME
1. a) Solution L coagulates. (1mk)
b). Stomach (1mk)
Function
- Kills any bacteria that may be present in food.
- Provides correct pH for the action of stomach enzymes. (Pepsin, rennin)
- Coagulates milk making it hold together for easy action of digestive enzymes. (Any one)
iii) a) Translucent spot /mark is formed. (1mk)
b) Fats /lipids present. (1mk)_
c) Translucent spot test /Grease spot test. (1mk)
iv)
FILTRATE
Food being tested Procedure Observation Conclusion

Starch to 2ml of filtrate in a test Brown color of starch absent

tube. Add 3-drop pf iodine iodine retained
solution. Shake (1 mk) (1/2 mk) (1/2 mk)

Proteins To 2ml of filtrate in a Purple color observed Protein present

test tube. Add 2ml of sodium (1/2 mk) (1/2 mk)
hydroxide solution and shake.
Add copper (II) sulphate
solution drop [by drop
and shake (1mk)

RESIDUE (4MKS)

Food being tested Procedure Observation Conclusion

Starch To 2ml of residue in test tube. Blue-black color observed starch present
Add 3 drop of Iodine solution (1/2 mk) ` (1/2 mk)
shakes (1 mk)

Proteins To 2ml of residue in clean tube. purple color observed protein present
Add 2ml of sodium hydroxide (1/2 mk) (1/2 mk)
solution and shake. Add copper
sulphate solution drop by drop
and shake (1 mk)

2. a) A Analogous structure
B Homologous structures
b). Swimming in water
c). Homologous structures are structure of similar embryonic origin but are modified to perform
different functions in different ecological niche, while Analogous structure are structure of different
embryonic origin that become modified in the course of evolution to perform similar functions in the
same ecological niche. (4 mks)
d). A Convergent evolution
B Divergent evolution (2mks)

Page | 76
e). Variation occurs in locomotory structure within the population brought about by the prevailing
environment. Hind limbs began to regress as the ancestors of whales entered the aquatic
environment over time; the whale descendants spend more and more time in the water and their
bodies become adapted for swimming. Their front legs become flippers. (2mks)
f) Distortion due to geological / activities
- Missing links due to decomposition (2mks)
3. a) i). Spermatophyta /spermaphyta. (2 mks)
Angiospermatophyta /angiospermae
ii) Presence of flower (1mk)
Body differentiated into leave, stem and roots.
b) Class monocotyledonae
Reason
Parallel venation
Flower has 3 petals
Has leaf sheath
c) Insect
Reason
Brightly coloured petal
d) V Stigma
W Staminal tube
P Bract
e) i). Bud
ii). Protect the flower during bud stage against mechanical damage.
iii). Petal is free / flower has 3 petals. ( 1 mk)

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 KIRINYAGA EAST CLUSTER EVALUATION
231/1
PAPER 1
TIME: 2 HOURS
1. (a) What is biochemistry? (1 mk)
(b) Name the organelle that will be most abundant in;
(i) Phagocyte cells . (1 mk)
(ii) Palisade cells . (1 mk)
2. Study the diagram below and answer the questions that follow.
Solution A Solution B
o o o
Semipermeable
membrane
o o o o
o o o o Water molecules
o o o Sugar molecule
o o o
o o

(a) Which solution has a higher concentration of free water molecules? (1 mk)
(b) Which solution is more concentrated? (1 mk)
(c) In which direction will osmosis occur? (1 mk)
(d) Give two roles of diffusion in plants. (2 mks)
3. (a) Name any two types of germination. (2 mks)
(b) State the role of the following germination.
(i) Coleorhiza (1 mk)
(ii) Hooked hypocotyl. (1 mk)
(c) Differentiate between;
(i) Apocarpous and syncarpous gynoecium. (1 mk)
(ii) Gamopetalous and polypetalous. (1 mk)
4. The equation below represents a process that occurs in green plants.
Light energy
2H2O 4H + O2.
(a) Identify the process above. (1 mk)
(b) What is the fate of:
(i) The hydrogen atoms produced. (1 mk)
(ii) The oxygen produced. (2 mks)
(c) State two ways in which chloroplasts are adapted to their function. (2 mks)
5. (a) Name three characteristics of a population. (3 mks)
(b) State three precautionary measures to control the outbreak of cholera. (3 mks)
6. The following equation represents a certain reaction.
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy
(a) Work out the respiratory quotient. (2 mks)
(b) Identify the substrate being oxidized in the reaction. (1 mk)
(c) Fats produce more energy than carbohydrates or proteins when oxidized, and yet are not the
main respiratory substate explain. (2 mks)
(d) State two factors other than oxygen concentration that can affect the rate of the above reaction.
(2 mks)
7. (a) Differentiate between homologous structures and analogous structures. (2 mks)
(b) Describe continental drift as evidence of evolution. (3 mks)
Page | 78
8. State the use of the following apparatus. (2 mks)
(a) Bait trap
(b) Sweep nets
9 a) State three distinguishing features of Aves (3mks)
(b) Draw a well labelled diagram of a trifoliate leaf with serrated margin and pointed leaf tip.
(3 mks)
10. Identify the type of gene mutation represented by the following pairs of words.
(i) Shirt instead of skirt (1 mk)
(ii) Hopping instead of shopping (1 mk)
11. Explain what happens to excess amino acids in the liver of humans. (3 mks)
12. A certain maggot was found to burrow quickly into decaying faecal matter as soon as it was
exposed to sunlight.
(a) Name the type of response exhibited by the maggot. (1 mk)
(b) Of what value is such a response? (2 mks)
13. Name two types of involuntary muscles in mammals. (2 mks)
14. Complete the table below. (4 mks)
Blood Group Can donate blood to Can receive blood from
A
B
AB A, AB,B,O
O A, B, AB,O

15 Explain why the respiratory surface has to be

(a) thin. (1 mk)
(b) moist (1 mk)
16. Give the causative microorganism of the following diseases.
(a) Syphilis (1 mk)
(b) Gonorrhoea (1 mk)
(c) Herpes (1 mk)
17. Colour blindness is a sex linked trait controlled by a recessive gene b. If a mother is a carrier
and the father is normal. What is the chance that their son will be colour blind? Show your
working. (4 mks)
18. Name three types of support tissue in plants. (3 mks)
19. State two functions of the human ear. (2 mks)
20. How are the lenticels adapted to their functions? (2 mks)
21. State any two diseases of the liver. (2 mks)
22. How is the low power objective lens manipulated to focus a specimen for observation under
light microscope? (2 mks)

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 KIRINYAGA EAST CLUSTER JOINT EXAMINATION
231/2
PAPER 2
TIME: 2 HOURS
1) A form three students carried out an experiment to show the effect of some conditions for seed
germination. The results were as in the table below. All other environmental conditions were
kept constant, except for the one being investigated.
EXPERIMENT TREATMENT %
Q Seeds placed in tightly closed container with
pyrogallic acid 0
R i) Seed kept in source of light 96
ii) Seeds kept in dark cupboard 97
T 0
I) Seeds kept in a refrigerator at 4 c 0.5
II) Seeds kept in an oven at 600c 0
III) Seeds kept at 350c 92
V i) Dry seeds in closed container 0
ii) Moist seeds in closed container 87

a) What was the purpose of pyrogallic acid in the experiment Q? (1mk)

b) State the aim of experiment R (1mk)
c) Account for the results obtained in experiment T (3mks)
d) State why 100% germination was not achieved in experiment V (ii) (1mk)
e) Of what biological significance is the condition necessary for germination being investigated by
experiment V (2mks)
2) In human population, some can roll their tongue into a U-shape. Others cannot no matter how
hard they try. This characteristic is controlled by a single pair of alleles represented by G and g.
a) If G is dominant, write down the possible genotypes of
i) Roller (2mks)
ii) Non roller (1mk)
b) A man and a woman both rollers of their tongues marry and produce some children who cannot
roll their tongues. Explain how this occurs by means of a punnet square (4mks)
c) Name the type of variation that explains this occurrence in human population (1mk)
3) One student in a certain secondary school observed the stem of the passion fruit twinning
around a post.

a) State the name given to the growth movement shown above (1mks)
b) What is the biological importance of this growth (1mk)
c) Account for the twinning growth response shown by the plant (3mks)
d) Name three other types of growth response exhibited by plants (3mks)

Page | 80
4) The diagram below represents recycling of nutrients in a certain ecosystem

a) Name the trophic level represented by Q (1mk)

b) Name the process represented by 1, 2 and 3 (3mks)
c) Name the organism involved in process 2 (1mk)
d) What would happen within the ecosystem if all secondary consumers were eliminate(3mks)
5) Diagram below shows section through mammalian nephron

a) (i) Name parts T , U (2mks)

(ii) Name one hormone that has an effect on part labelled U and where it is produced (2mks)
(II) How will the concentration of urine be affected at region X in the absence of hormone referred
to in a(i) above (1mk)
(III) Name the fluid found in part labelled T (1mk)
(IV) Which conditions are responsible for formation of fluid of part labelled T (2mks)
SECTION B
Question 6(compulsory) in the spaces provided and either question 7 or 8
6) Cells of zebrina plant were found to have an average diameter of 2.5cm. The cells in each
solution were determined and results obtained were shown below
Percentage sugar concentration Diameter of cells (mm)
1 5.0
5 4.0
10 3.0
15 2.0
20 1.5
25 1.0

a) Draw a graph of diameter of cells against percentage sugar concentration (6mks)

b) From the graph determine the concentration of cell sap (1mk)

Page | 81
c) Give an explanation for the average diameter of cells placed in 2.5% sugar (4mks)
d) Describe the difference in appearance between cytoplasm and after cells being placed in 25%
sugar solution (2mks)
e) Define the following terms
i) Permeable membrane (1mk)
ii) Semi-permeable membrane (1mk)
f) State three main processes by which substances pass across a cell membrane (3mks)
g) Give two properties of cell membrane (2mks)
7) Describe the process of fertilization in flowering plants (20mks)
8) a) How are xerophytes adapted to their habitat (10mks)
b) Discuss application of genetics in health care today (10mks)

KIRINYAGA EAST CLUSTER

paper 3
231/3
3
Time 1 Hrs
4
CONFIDENTIAL
Requirements:
Eggs, 3 TT, 50 ml or 100 ml beakers, means of heating, TT holders, a dropper.

Reagents
Benedicts solution, Iodine solution, DCPIP, sodium hydroxide, copper sulphate 10ml
suspension

To prepare X
1 egg extract in 500l of distilled water

Page | 82
 KIRINYAGA EAST CLUSTER
paper 3
231/3
3
Time 1 Hrs
4
1. You are provided with specimen labelled X in a small beaker. Using reagents provided test for
the food substances. (12mks)
b) State TWO functions of food (s) present in substance X. (2mks)
2. You are provided with a photo of a specimen as shown below

(a) Identify the…

(i) Kingdom (1mk)
(ii) Phylum (1mk)
(iii) Class (1mk)
Give TWO reasons for the class. (2mks)
(b) In the photograph label fins for ;
(i) Forward movement as A (3mks)
(ii) Balancing as B
(iii) Staying upright as C
(c) Make a well labelled diagram of a gill. (5mks)
3. The following organisms are located in a grassland environment.
Eagles, Lizard, Grasshopper, Termite, Goats, Chicken, Cheetah and vulture.
a) Construct a food web from the organisms listen above. (6mks)
b) Lions were introduced into this ecosystem. Explain how they affect the following organisms in
the ecosystem. (2mks)
i) Cheetahs
ii) Goats
c) The photograph below depicts an interaction of organisms in a certain ecosystem.

R Q
(i)What feeding relationships are exhibited by the animals shown in the photographs.? (1mk)
ii) State the adaptations of animal R regarding its feeding relationship mentioned in c (ii) above.
(4 mks)

Page | 83
 KIRINYAGA EASTERN CLUSTER EVALUATION
231/1
PAPER 1
MARKING SCHEME
1. (a) Study of chemistry of materials /chemical change or reactions that take place inside the cells of
living organisms. (1 mk)
(b) (i) Lysosomes (1 mk)
(ii) Chloroplasts (1 mk)
2. (a) Solution B (1 mk)
(b) Solution A (1 mk)
(c) Move from solution B to solution A (1 mk)
(d) Absorption of material (mark correct example e.g Absorption of dissolved mineral
salts from the soil (1 mk)
Gaseous exchange (1 mk)
3. (a) Hypogeal
Epigeal (2 mks)
(b) (i) Protect the radicle as it pushes down the soil (1 mk)
(ii) Protect plumule as it pull out of the soil (1 mk)
(c) (i) Apocarpus gynoecium is a polycarpus (having many carpels) with free carpels
Syncarpous gynoecium - is a polycarpus gynoecium with fused carpels (1 mk)
(ii) Gamopetalous - These are fused petals
Polypetalous - These are petals that are free (1 mk)
4. (a) Photolysis (of water) (1 mk)
(b) (i) Enter/used in dark stage/used in carbon (iv) oxide fixation (1 mk)
(ii) Some used in respiration
Excess is released into the atmosphere (2 mks)
(c) They contain chlorophyll which traps/absorb light energy.
They have grana which increase surface area for accommodation of large number of
chlorophyll molecules.
The stroma has enzymes for photosynthesis; any two (2 mks)
5. (a) Population density
Population dispersion
Population growth (3 mks)
(b) Proper disposal of faeces/refuse
Maintain high standard of personal hygiene
Drinking boiled & filtered or chlorinated water
Mark correct example if given (3 mks)
6. RQ = (Volume of) CO2 produced
(Volume of) O2 consumed
= 6 = 1.0 (2 mks)
6
(b) Carbohydrate/glucose (1 mk)
(c) Because fats are not very soluble hence not easily transported to the respiratory sites;
one gram of fat require more oxygen to oxidise than one gram of glucose. (2 mks)
(d) Temperarure Body size/S.A to V.R
Substrate concentration Hormones
PH
Age/activity any two (2 mks)
7. (a) Homologous structures are structures that have a common embryonic origin but are
modified to perform different function, while analogous structures are structures with
different embryonic origin but have been modified to perform the same function
(b) Current continent existed as one large land mass/pangea; The present continents drifted leading

Page | 84
 to isolation of organisms; organisms in each content evolved along different lines; hence
emergence of new species. (3 mks)
8. (a) Bait trap - for attracting and trapping small animals e.g rats
(b) Sweep net - for catching flying insects
9. (a) Body covered with feathers
Have beaks
Hollow bones
Hind limbs have scaly skin (3 mks)

(b)

10. (i) Substitution (1 mk)

(ii) Deletion (1 mk)
11. Explain what happens to excess amino acids in the liver of humans. (3 mks)
They are broken down (deaminated); Amino group is removed and used to form ammonia;
Ammonia taken into the ornithine cycle to form urea; urea is finally passed out in the urine through
the kidney;
The remaining organic compound are converted to glucose. (Which is oxidised to provide energy) ;
12. (a) (negative) Phototaxis (1 mk)
(b) Escape from predators
Avoid dessicaton/loss of water from the body. (2 mks)
13. Smooth muscles
Cardiac muscles (2 mks)
14. Complete the table below.
Blood group Can donate blood to Can receive blood from
A A, AB A, O
B B, AB B, O
AB AB A, AB, B, O
O A, B, AB, O O

15. Thin - for faster diffusion of gases over a short distance. (1 mk)
Moist - for dissolving gases. (1 mk)

16. (a) Treponema Pallidum (1 mk)

(b) Neisserra gonorrhoea (1 mk)
(c) Herpes simplex (1 mk)

17. Parental genotype

gametes

Chance = ½ ;
18. Parenchyma
Collenchyma
Sclerenchyma
Xylem
19. Perceve sound/hearing
Maintainof body balance/posture
Page | 85
20. Have corkcell which are loosely packed to facilitate air circulation;
The corkcells have moist surfaces to dissolve respiratory gases.
21. Liver cirrhosis
Hepatitis
Jaundice
22. Click the low power objective lens in positions; with eyes on the eye piece lenses and using
adjustment knob gradually raise/lower the low power objective lens to bring specimen into focus.

Page | 86
 KIRINYAGA EAST CLUSTER JOINT EXAMINATION
PAPER 2
MARKING SCHEME
1.
a) Absorbs oxygen;
b) Investigate if light is necessary for germination;
c) At 600c high temp above optimum Denatures enzymes/kills cells protoplasm hence no
germination;
At 350c -optimum temp hence highest germination;
At 40c-temp below optimum enzymes are inactive hence little germination;
d) Some seeds are not viable;
e) Water softens seed coat/water transports dissolved food substances/activate enzymes; and
provide medium for enzyme action and breaks down stored food into soluble food; Hydrolysis
and dissolves materials; any two
2) i) RR; Rr;
ii) rr;
b) Genotype Rr x Rr ;
R r
R; RR; Rr
r Rr Rr;
c) Discontinuous variation;
3) a) Haptotropism/thigmotropism;
b) plant get support from other plants to obtain light
c) i) as the stem gets into contact with a hard object, auxins migrate to the side not in contact
/laterally; high auxin concentration stimulates faster growth on the opposite side than the
point of contact with object; causing them to curve;
ii) phototropism;
Geotropism;
Hydrotropism;
4) a) primary consumers;
b) i)predation/feeding;
2) decomposition /decay/predation;
3) absorption;
c) decomposers/bacteria/fungi/saprophytes;
d) Primary consumers/organisms in box Q would increase in numbers; leading to overgrazing
leading to decrease in number of producers; leading to decrease in numbers of primary
consumers;
5) T-Bowman’s capsule;
U- Distal convoluted tubule
II)Anti diuretic hormone/vasopressin;
Pituitary gland;
b) Dilute urine formed;
c) Glomerular filtrate/ capsular fluid;
d) narrower efferent arteriole;
high pressure from pumping action of heart;
narrow glomeruli capillaries ;
tiny pores in capsular wall/endothelium of glomeruli; any two

Page | 87
6) a)

b) 12.5%;
c) 2.5 solution is hypotonic to the cells cell sap; water was drawn into the cells by osmosis; the
cells became turgid; increased the size;
d) before- more;
after-reduces;
e) i) membrane that allows all substances to pass through freely;
ii) membrane that allows some molecules to pass across and not others;
f) Osmosis
- diffusion
- active transport
g) polarity
sensitive to changes in temperature and PH
semi-permeable;
first two.
7) pollen grains land onto the stigma; and adhere to it as a result of the stigma cells secreting sticky
substance; it absorbs nutrients ; and germinates forming a pollen tube; pollen tube grows down
the style to the ovary;deriving nourishment from the surrounding tissue; pollen tube has tube
nucleus at the tip; and generative nuclueus immediately behind it;
As the tube grows down wards into the ovary the generative nucleus divides mitotically; to
give rise to two nuclei; which represent the male gametes; pollen tube penetrates the
ovule/embryo sac through the chalaza/micropyle;
After pollen tube enters embryo sac tube nucleus breaks down ; leaving a clear passage for
the entry of male nuclei; into the embryo sac; where one fuses with the egg (cell) nucleus
/ovum/egg cell/oosphere; to form diploid zygote; which develops into embryo; the other male

Page | 88
 nucleus fuses with two/both polar nuclei; to form triploid nucleus/primary endosperm nucleus;
which becomes endosperm. This is called double fertilization;
8)a) Leaves covered with thick/waxy cuticle; that is water proof/impermeable; to water; reducing
rate of transpiration;
Sunken stomata; water vapor accumulates in the pits; reducing rate of transpiration
Have few or no stomata on the upper surface of the leaf/more stomata on lower surface
sheltered from direct sunlight; the fewer the stomata the less the transpiration, some plants have
small stomata/small stomatal pore; reducing transpiration rate.
Plants with small/needle like leaves/spines; expose less surface area; hence reduce
transpiration rate. Leaves with shiny surface; reflects light reducing leaf temperature; reducing
rate of transpiration.
Some plants have leaves covered with hairs/scales; which trap a layer of moisture ;
reducing rate of transpiration.
Mark rate of transpiration once where it occurs first
Max 10
b) Developments of vaccines; useful in curbing diseases and providing immunity; Genetic finger
printing used in crime detection; blood typing; essential in blood transfusion;
Genetic counselling is used to provide information on genetic disorders; also informs
affected person on the risks associated with the disorders;
Important hormones have been developed; e.g insulin hormone; for management of
diabetes mellitus; growth hormones have been produced; and used to remedy growth related
problems; developing antibiotics; for curbing bacterial diseases;

Page | 89
 KIRINYAGA EAST CLUSTER
paper 3
231/3
3
Time 1 Hrs
4
1. (a) Marking Scheme (12marks)

Food substance Procedure Observation Conclution

Proteins(s) To solution X, Solution turns Protein is
Add drops of sodium Pulple present
Hydroxide and shake
Then add Copper
sulphate drop by drop
To food substance add Blue colour
Reducing sugars of Benedict’s solution Remains/persists Reducing sugars is
and heat /boil No colour change absent
To DCPIP, No colour Absence of vitamin C
Add some solution X Change or rej vit/vitc
Vitamin C Colour of DCPIP
Ascorbic acid remains
To X in a Iodine colour Starch
Test tube add Remains/ is absent
Starch Some Iodine Brown colour
solution remains
No colour
change
(b)(i) – Body building food
-Growth and development
-Source of energy during extreme starvation
- Formation of enzymes/hormones/antibodies
- Formation pigments e.g. haemoglobin/ myoglobin
- Formation of structures e.g. hairs and nails:
2. (i) Animalia
(ii) Chordata

(iii)Pisces
Reason i) Has gills
ii)Operculum
iii)Scales
iv)Lateral line
b.
A- Tail/caudal fin
B- Pectoral/pelvic fin
C- Anal/ventral fin/dorsal fin

Page | 90
c.

D1- Gill rakers smaller than gill filaments

Rakers not together e.g.
D2- Continues outline
Gill filaments not hanging 8mks

3.a)

NB: Award a mark each for any 6 correct /complete food chains extracted from the food web.
b) i) Cheetahs - decreases since Lion is a competitor to it/ have the same prey. (2 mks)
ii) Goats – decrease since another predator has been introduced.
c) i) Prey-Predator relationship
ii) – High speed (4 mks)
- Leaps on prey
- Powerful sharp canines for seizing prey
- Special carnassial teeth on the upper jaw for crushing bones.
- Binocular vision giving ability to accurately judge distance of prey for a fruitful leaping.

Page | 91
 IGOJI SUB-COUNTY
231/1
PAPER 1
THEORY
TIME: 2 HOURS
1. The diagram below illustrate tissue fluid and cells surrounding a capillary.

Name the component found in fluid G (3mks)

2. Name the cell organelle found in abundance in white blood cells and give a reason. (2mks)
3. Give two observable features that place man into his class (2mks)
4. When a flesh leaf is placed in hot water air bubbles are formed on the surface of the leaf.
a) Name the structure from which the bubbles were coming from? (1mk)
b) Name the biological process being investigated (1mk)
5. Explain the role of thrombin in blood (2mks)
b) Name the anticlotting factor in the human blood (1mk)
6. A short man with beard and pimples on his face and limps.
a) List two inherited features (2mks)
b) Explain why most recessive genes are expressed phenotypically in male in humans
(2mks)
7. What is meant by the term etiolation? (1mk)
b) Give the significance of etiolation (2mks)
8. The diagram below illustrates a germinating seed

(a) Name the type of germination (1mk)

(b) Give reason for your answer in (a) above (1mk)
9. What causes seed dormancy (3mks)
10. State the functions of the following part of a microscope (3mks)
Diaphragm
Condenser
Objective lens
11. Name the characteristics of living organism shown by each of the following? (3mks)
(a) Budding in yeast
Page | 92
(b) Enlargement of eye pupil in dim light
(c) Sweating after an exercise.
12. A student left a piece of bread on an open place accidentally. After three days he observed some
black substance developing.
(a) Suggest the identity of the black that grew on the bread? (1mk)
(b) Explain how the black substance is formed (2mks)
(c) State the kingdom to which the organism belong? (1mk)
13 Name two specialized cells in animals (2mks)
14. The diagram below illustrates a nerve cell

a) Name the type of nerve cell illustrated (1mk)

b) Give a reason for your answer in i (a) above (1mk)
c) Identify the part labelled J (1mk)
d) State one function of the part labelled H. (1mk)
15. The diagram below illustrates the role played by red blood cells in the transportation of carbon
(IV) oxide.

a) Other than the carbon (IV) oxide transportation in the red blood cells, name the form which
carbon (IV) oxide transportation in humans. (1mk)
b) i) Name substance F (1mk)
ii) Name the enzyme marked G and state its role in the reaction. (2mks)
Enzyme
Role
16.) During an ecological visit to the Savanna Grassland, students were able to see lions, Antelopes,
vultures and pastoralists grazing their cattle. Construct a food chain with four consumer levels
to illustrate the energy flow in the ecosystem. (2mks)
17. How is a human stomach adapted to
i) Protein digestion? (2mks)
ii) Churning? (2mks)
18. a) State two ways in which the muscles of the mammalian heart are special. (2mks)
b) Name the type of muscles found in the following organs (2mks)
(i) Stomach
(ii) Bone
Page | 93
19. State the importance of tactic responses among members of Kingdom Protista (2mks)
20. An organ is with an exoskeleton, segmented body, two pairs of legs per segment, a pair of eyes
and a pair short antennae belongs to the
phylum (2mk)
class
21. Why are two organisms considered to belong to the same species (2mks)
22. State the part of the eye involved in (3mks)
a) Colour vision
b) Maintaining the shape of the eye ball
c) Change the diameter of the lens
23. Name three physical movement during exhalation (3mks)
b) What do you understand by the term hypoxia (1mk)
24. Explain why most plants growing in water logged areas die before maturity? (3mks)
25. To estimate the population size of crabs in a certain pond, traps were laid at random. 600 crabs
were caught, marked and released back into the pond. Four days later, traps were laid again and
crabs were caught. Out of the 574 crabs, 100 were found to be marked.
a) Calculate the population size of the crabs in the pond (2mks)
b) State two assumptions that were made during the investigation (2mks)
c) What is the name given to this method of estimating the population size (1mk)
26. The diagram below shows a section through the mammalian skin.

a) Name the parts labeled A, F and B. (3mks)

b) State function in each case of substance secreted by the structures labeled. (2mks)
(i) B
(ii) E

Page | 94
 IGOJI SUB-COUNTY
231/2
PAPER 2
TIME: 2 HOURS
1. a) What is meant by the term genetics? (1 mark)
b) State two examples of discontinuous variation. (2 marks)
c) A female with sickle cell trait marries a normal man. The allele for sickle cell is Hbs and the
normal allele is HbA. Determine the probability that their first born will have the sickle cell
trait. Show your working. (5 marks)
2. In an experiment to investigate a plant response, the set up shown in the diagram below was
used.

(a) Name the type of response that was being investigated. (1 mark)
(b) If the Klinostat was not rotating:
(i) State the observations that would be made on the seedlings after three days; (2 marks)
(ii) Explain the observations in (b) (i) above. (3 marks)
(c) If the experiment was repeated with the Klinostat rotating:
(i) State the observation that was made on the seedlings after three days; (1 mark)
(ii) Give a reason for the observation made on the seedlings. (1 mark)
3. The figure below represents an organ obtained from a section of a plant. Use it to answer
questions that follow.

a) i) Name the organ from which the above section was obtained. Give a reason for your
answer (2marks)
ii) Structure labelled J is described as a mechanical tissue. Explain (1mark)
b) i) Name the process by which water passes across structure M (1mark)
ii) Explain two ways by which cells with structures D are adapted to their functions
(2marks)
c) Name two strengthening materials that strengthen the collenchyma tissue (2marks)

Page | 95
4. The diagrams below illustrate the behaviour of Red Blood Cells when placed into two different
solutions X and Y.

a) Suggest the nature of solutions X and Y. (2marks)

b) Name the processes A and B (2marks)
c) What would happen to plant cells if they were placed in an isotonic solution? (1mark)
d) Explain the mechanisms by which mineral salts moves from the soil into the root hair cell in
plants (3marks)
5. The diagram below shows two cells, X and Y from the same organism. Study the diagrams and
answer the questions that follow.

(a) Name the parts labelled A, B and C . (3 marks)

(b) i) Which cell is diving by meiosis? (1 mark)
ii) Give two reasons for your answer in (b) (i) above (2 marks)
c). what is the significance cell division on cell Y (2marks)
SECTION B (40 MKS)
Answer question 6 (Compulsory) and either question 7 or 8 in the spaces provide after
question 8
6. The glucose level in mg/100cm3 of blood was determined in two persons Y and Z. Both had
stayed for 6 hours without taking food. They were on equal amount of glucose at the start of the
experiment. The amount of glucose in their blood was determined at intervals. The results are
as shown in the table below:
Time (Mins) Glucose level in Y Blood in mg/100cm3
0 85 78
20 105 110
30 116 130
45 130 170
60 100 195
80 93 190
100 90 140
120 90 130
140 88 120

(a) On the same graph and on the same axis, plot a graph of glucose level in blood against time
Page | 96
(b) What was the concentration of glucose in blood of person Y and Z at 50th minute? (2marks)
Person Y
Person Z
(c) Account for the level of glucose for a person Y
(i) During the first 45 minutes (2maks)
(ii) After 45th minute to the end (4marks)
(d) Discuss the effect of higher glucose level in blood above 90mg/100cm3 (3marks)
(e) State two advantages of homoitherms over poikilotherms (2marks)
7. a) How does excretion take place in plants? (4 marks)
b) Describe the role of the human skin in homeostasis. (16 marks)
8. Describe causes and methods of controlling water pollution (20 marks)

IGOJI SUB-COUNTY
231/3
PAPER 3
CONFIDENTIAL
1. Twelve Specimen N (Soaked bean seeds soaked for 4days)
2. Indicator D (bromothymol blue)
3. Cotton wool (substantial amount)
4. Wooden splint
5. 2 test tubes in a rack
6. Means of timing

Page | 97
 IGOJI SUB-COUNTY
231/3
PAPER 3
1. You are provided with several specimens N and indicator D, which is Bromothymol blue. Study
them and answer the questions that follow:
(a) i) Identify the part of plant represented by specimen N. (1mk)
ii) Give a reason for your answer in a) i) above. (1mk)
(b) i) Name the physiological process which is taking place in specimen N. (1mk)
ii) Describe the two changes which occurred to specimen N during the process named in b)i)
above. (2mks)
(c) i) State two internal factors which would promote the physiological process exhibited by
specimen N, (2mks)
ii) State two external conditions which would inhibit the process demonstrated by specimen N.
(2mks)
(d) Take a small piece of cotton wool and insert into a test tube. Use a wooden splint to push it to
the bottom. Add two drops of indicator marked D, and spread it uniformly in the cotton wool by
pressing using the wooden splint. Drain the excess indicator and then add 10 pieces of specimen
N into the test tube. Close the mouth of the test tube tightly using the remaining cotton wool.
Leave the set up to stand on the tube rack for 20 minutes.
(i) Record your observation after 20 minutes (1mk)
(ii) Account the observation in d) i) above (3mks)
(iii) Suggest a control for his experiment. (1mk)

(a) Name the parts labeled K, F, X,A and H (5mks)

(b) State two adaptations of part labeled H to its function (2mks)
(c) From the name the part where;
(i) Counter current flow occurs (lmk)
(ii) Reabsorption of water occurs (1mk)
(iii) Name the metabolic wastes components in the blood that do not enter the renal tubule
(d) Explain what would happen to the process of urine formation in absence of anti-diuretic
hormone (3mks)
3. Photographs A, B, C, D, and E below represent organisms that occupy a certain Ecosystem
studied on a field visit.

Page | 98
 C B
D
E

(a) Using the letters assigned to each organism, construct two food chains ending with a Tertiary
consumer. (2mks)
(i) Suppose organism B migrated out of this ecosystem, suggest two possible effects on the
ecosystem. (2mks)
(ii) Using observable features only, state the adaptations of organism A to different ways of
locomotion. (3mks)
(b) Carefully observe feet from four different birds labeled G, H, J, and K
K J
H G

(i) What evolutionary concept is shown by these feet? (1mk)

(ii) State the functional adaptations shown by the feet labeled G, J, and K (3mks)
(iii) For the feet H and G, state the observable features that suit the birds to that environment.
(2mks)

Page | 99
 IGOJI SUB-COUNTY
PAPER 1
MARKING SCHEME
1. – platelets
- White blood cells
- Plasma protein
- Mineral salts
- Water
2. Lysosomes
- Contain lytic enzyme that digest engulfed pathogens
3. Has mammary glands
- Body covered by hair
- Heterodont dentation
- Have two pinnae
- Internal fertilization
4. Stomata
b) gaseous exchange
5. Activates conversion of fibrinogen to fibrin which forms mesh work of fibres.
b) Heparin
6. a) height; beards
b) male have only one X chromosome; if it carries gene for trait the gene is expressed
phenotypically since allele on Y chromosome is absent.
7. Plant grow long, pale and unhealthy due to lack of light;
b) elongate toreach light before stored food is exhausted;
- enable the shoot to break the ground before food reserve is exhausted;
8. Hypogeal;
b) hypocotyl is above the cotyledon
9. Immature embryo
- Hard testa
- Chemical inhibitors
10. Regulate the amount of light passing to the stage
- Concentrate light to the stage
- Contribute to magnification of the specimen.
11. a) reproduction
b) movement; irritability
c) excretion
12. Rhizopus
b) spores are deposited on the bread ;germinate into hyphae mature into sporangiosphores which
contain the spores which mature dry and turn black.
c) Fungi
13. Nerve cell
- Spermatozoon
- Epithelial cell
- Red blood cell
14. Sensory neurone
- Cell body is located outside axon
- Unipolar
c) Schwann cell
d) insulate to increase impulse propagation;
15. Carbaminohaemoglobin; carbonic acid;
Page | 100
- Water
- Carbonic anhydrase
- Catalyse conversion of carbon (iv) oxide to form weak carbonic acid;
16. Grass → antelope → lion → vultures
Grass → cattle → lion → vultures
17. Produce mucus which line the stomach wall to prevent digestion by enzymes;
- Produce hydrochloric acid that activate digestive enzymes
(ii) has smooth muscles which moves by peristalsis causing movement of chime.
18. Myogenic
- Presence of intercalated disc;
b) smooth muscle
ii) stiriated
19. Evade hash environmental condition;
- Moving to favourable conditions;
20. Arthropoda
- Millipede
21. When they can freely interbreed to produce viable offspring;
22. Cones
b) rectus muscle
c) ciliary muscle
23. Rib cage moves inwards and outwards; diaphragm relax to doom shaped;
b) Deficiency of oxygen to body tissues;
24. Water logging cut off oxygen supply to the root; preventing aerobic respiration which interfere
with active transport hence no uptake of minerals salts causing death;
600 𝑥𝑥 574
25. = 3444crabs
100
b) there were no migration
death rate is equal to birth rate
26. A cornified layer
F dermis
B sweat gland
B
Moisturize the epidermis to keep it supple and prevent desiccation;
Contain antiseptic substance to protect against invasion by microorganism;
E
To regulate temperature through loss of excess heat by evaporation of water
Excretion of metabolic waste;

Page | 101
 IGOJI SUB-COUNTY
PAPER 2
MARKING SCHEME
1. Study of inheritance and variations
b) Tongue roller and tongue roller
- present and absent of ear lobes
c.)
S S S A
HB HB HB HB

X
S
HB S
HB
S
HB A
HB

S S
HB HB

S S
HB HB S A
S A HB HB
HB HB

- Probability is half
2. a) hydrotropism
b i) radical of the bean seed will grow toward the damp cotton wool and downwards and shoot
upwards.
ii) Radical is positively hydrotropic hence move towards damp cotton wool
Radical is positively geotropism while shoot is negative geotropism.
c) The plant will grow horizontally
ii) Gravitational effect will be cancelled by the rotation of klinostat
3. a) i) Root/dicot root/Dicotyledonous root reject monocot root.
ii) It contain lignin deposits/it is lignified to provide support.
b) i) Active transport; reject osmosis
ii) – Presence of root hairs
iii) Contain lignin deposits /lignified to provide support.
- Contain a large sap vacuole that has high concentration of soluble to raise its osmotic pressure
to that become hypertonic thereby facilitating water uptake by osmosis from the soil.
- Thin walled for rapid movement of water and mineral salts into the cell.
- Thin & flexible to penetrate between soil particles to reach the water table.
- Numerous mitochondria to generate enough energy helped for certain uptake of mineral ion
from the soil.
c) Cellulose; pectin
4. a) X = Hypotonic solution
Y = Hypertonic solution
b) A = Haemolysis
B = Crenation
c) The cell will maintain / retain its normal shape.

Page | 102
d) Plant root hair will take in salts by diffusion/ active transport; this will make the cytoplasm to be
hypertonic; hence water will move into the root hair cells by osmosis;
5. A- chromatids
B – spindle fibres
C – crossing over
b) Y
- homologous chromosomes separating after cross over
- crossing over
c) maintain the number of chromosomes in the cells by producing haploid gametes.
6. Graph
Scale 2mks
Plot 2mks
Axis 1mk
Curve 2mks
b) Y..... 120mg/100cm3 ± 1; 1mk
Z.... 178mg/100cm3± 1; 1mk
c) i) Blood glucose level increased ;to (130mg/ 100cm3) as more glucose is being absorbed from
gut/ileum;
ii) Glucose concentration declined to normal 90mg/ 100cm3; increase in glucose level stimulated
pancreas to release insulin ; which stimulates the liver cells to convert excess glucose to
glycogen (for storage) ;. Increased respiration of glucose;
d) Higher blood glucose – increase the osmotic pressure of tissue fluid; hence loss of water from
cells by osmosis; This disrupts normal cellular functions;
e) Can occupy most ecological zones;
Ever active due to maintenance of optimum body temperature throughout;

7. The gaseous wastes, oxygen, carbon dioxide, and water vapor are removed through the stomata
of leaves and lenticels of stems.
Some waste products collect in the leaves and bark of trees. When the leaves and bark are shed,
the wastes are eliminated.
Some waste products are rendered harmless and then stored in the plant body as solid bodies.
Raphides, tannins, resins, gum, rubber, and essential oils are some such wastes
The oil produced from orange, eucalyptus, and jasmine, latex from the rubber tree, papaya tree,
and gums from acacia, are different forms of stored waste products. Sometimes these products
are even excreted into the soil.
7.(b) When body temperature is lowered below normal; arterioles in the skin constrict; blood is
diverted to a shunt system; less blood flows to the skin/less heat is lost; when body temperature
is raised above normal; arterioles in the skin dilate; more blood flows to the skin; more heat is
lost by convection and radiation; when body temperature is lowered below normal: erector-pilli
muscles contract, hair stands erect; more air is trapped, air is a bad conductor; and insulates the
body against heat loss; when body temperature is raised above normal: erector-pilli muscles
relax, hair lies on skin; less air is trapped, more heat is lost; when body temperature is lowered
below normal: less fluids are absorbed by sweat glands; less sweating, less vaporisation of
water; when body temperature is raised above normal: sweat glands are more stimulated and
more sweat is produced; water in sweat evaporates and takes up heat from the body;body is
cooled/body temperature is lowered;
8. causes
- industrial discharge
- sewage discharge
- mining
Page | 103
- agricultural chemicals
- radio active waste
- oil spilage
Control
Minimize use of fertilizers and pesticides hence use ecofriendly fertilizer and chemicals
(organic farming)
Avoid littering open water bodies with plastic products
Prevent chemicals disposal into water bodies
Chemical precipitation to remove toxic substances from water before discharging it
Bio remediation by using microorganism to remove natural contamination
Sewage treatment and recycling to horticultural farming
Riparian buffer creation to shield water bodies from human activities
Treatment of industrial waste before releasing it
Collection of urban water into a common pool that filter run off to prevent pollution water
bodies
Cooling water before discharging it into water bodies.
Use of plastic pipes instead of lead pipes
Educating community on water control
Enhancing legislative policies that prevent water pollution.

Page | 104
 IGOJI SUB-COUNTY
PAPER 3
MARKING SCHEME
1. a)
i) Seed;
ii) It has one scar / point of attachment to placenta
(b) i) Germination;
ii) Water moves into the seed through the micropyle by imbibition; the seed swells; stored
food become hydrolyzed / enzyme break down the stored food into soluble products; the
embryo uses the soluble nutrients leading to radical coming out through the micropyle;
(c) i) - immature embryo
- Absence of growth inhibitors
Presence growth hormones;
Hard / impermeable testa; (1st 2 point
ii) – Absence of light;
- Low / freezing / chilling temperature
- Lack of moisture (1st 2 point
(d) i) The indicator D turned yellow;
ii) The soaked seeds carry out respiration; which produces CO2; which in turn changes the
indicator from blue to yellow;
iii) Use boiled seeds / dry seed;
2. (a) K - Afferent arteriole F - Ureter
X -cortex A -bowman’s capsule
H -proximal convoluted tubule
(b) - Coiled to increase Surface area for reabsorption of substances
- The tubule is supplied with blood capillaries to transport reabsorbed substances;
- lining cells have numerous mitochondria to provide energy in form of adenosine triphosphate
for active reabsorption.
- Cells of the tubule have microvilli which increases the surface area for reabsorption.
(c) i) -Loop of Henle
ii) - Distal convoluted tubule;
(d) Kidney tubule becomes less permeable to water; less water reabsorbed into blood stream;
Production of large amounts of dilute urine (thus diuresis).
3. (i) Food chain ending with Tertiary consumer
C → A → D → E
C → A → D → B
ii) Population of organism E (snakes) would increase leading to decrease in population of
organism D (frogs)
Population of organism A (grasshoppers) would increase hence grass would reduce;
iii) - has wings for flight;
- has three pairs of jointed legs for walking;
- Hind limb is highly muscular for hopping.
b) (i)- Divergent evolution / Adaptive radiation;
ii) G; capture and tearing prey
J; grasping twigs/branches;
H; wading/paddling in water;
iii) - H; webbed feet;
G; sharp curved talons/claws;

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 NYERI CENTRAL
231
PAPER 1
2 HOURS
1. The diagram below shows human female reproductive system

a) Name the parts labelled: B ,E (2 marks)

b) Name one hormone produced by the structure labelled A. (1 mark)
c) State the function of the structure labelled: B,C (2 marks)
2. Give reasons for carrying out the following procedures when preparing temporary slides.
a) Cutting very thin sections. (1 mark)
b) Placing the sections in water (1 mark)
c) Staining the section with iodine solution before observing. (1 mark)
3. The diagram below shows the relationship between the direction of blood flow and that of water
in the respiratory surface of a certain organism.

(i) What term is used to describe the above relationship? (1 mark)

(ii) State the significance of the relationship in (i) above. (1 mark)
4. Which sex chromosomes are found in human:
(a) Sperm cells (1 mark)
(b) Ova? (1 mark)
5. (a) Pregnancy continues if the ovary of an expectant mother is removed after the
4th month. Explain. (2 marks)
(b) Explain why mammalian testes are located to hang outside the body. (2 marks)
6. How is guard cell structurally adapted for gaseous exchange? (2 marks)
7. State the function of the following cell organelles.
(a) Lysosome (1 mark)
(b) Mitochondrion (1 mark)
8. Name the type of movement that occurs within a plant cell. (1 mark)
9. Students observed that the smell from a decomposing animal carcass was stronger at midday
than early in the morning.
(a) Name the physiological process by which the smell reached the students. (2 marks)
(b) Account for observation made by the students. (2 marks)
10. State three ways in which osmosis is significant to plants. (3 marks)
11. In cats the gene for fur colour is sex-linked. Letter G represents the gene for ginger fur colour
while letter B represent gene for black colour in a given cat species. These genes are co
dominant. Heterozygous females have ginger and black patches of fur and their phenotype is
described as tortoise shell.
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(a) With reference to the information above, what is meant by the term co-dominance.
(b) A tortoise shell female was crossed with a black male. Determine the genotypes and
phenotypes of the offspring. (4 marks)
12. State two reasons why humans are not commonly used as specimens for genetic studies.
13. (a) Name the disease in humans that is caused by lack of vitamin C. (1 mark)
(b) When is glycogen which is stored in the liver converted into glucose and released into the
blood. (1 mark)
14. (a) What is meant by the term digestion. (2 marks)
(b) (i) Give one example of a metallic co-factor. (1 mark)
(ii) Name a fat soluble vitamin manufactured by human body. (1 mk)
15. Below are diagrams of three leaves A, B and C. Construct a two steps dichotomous key which
can be used to identify each of them. (2 marks)

16. (a) Give three reasons why classification is important in biology. (3 marks)
(b) Name the unit of classification that has the least organisms. (1 mark)
17. State the importance of negative phototaxis to terminate. (1 mark)
18. The diagram below illustrates a response by a certain plant….

(a) Name the type of response (1 mark)

(b) Explain how the response illustrated above occurs (3 marks)
19. The diagram below represents a member of the kingdom Animalia.
(i) Name the phylum to which the organism belongs. (1 mark)

(ii) Using observable features in the diagram, give three reasons for the answer in b(i) (3 marks)
20. In an accident a victim suffered brain injury consequently he had loss of memory. Which part
of the brain was damaged? (1 mark)

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21. The figure below shows the surface view of a human brain.

(a) Name the parts labelled B,C and D (3 marks)

(b) State the functions of the part labelled B. (1 mark)
22. A person was found to pass out large volumes of urine frequently.
Name the:
(a) Disease the person was suffering from (1 mark)
(b) Hormone that was deficient (1 mark)
23. Explain how marine fish regulate their osmotic pressure. (4 marks)
24. The diagram below shows the exchange site between circulatory system and body cells.
(a) Explain two adaptations of the capillaries. (2 marks)

b) i) Name the blood cells labelled B. (1 mark)

ii) State the gas that diffuse from B to the tissue cells. (1 mark)
(c) i) Name the cell labelled C (1 mark)
ii) State what is happening to the cell named in c(i) above. (1 mark)
25. State two adaptations of the epidermis of a mesophyte that enables it to play a role in
photosynthesis. (2 marks)
26. A potted plant was kept in the dark for 48 hours. Two leaves X and Y were treated as shown in
the diagram below.

The experiment set-up was kept in sunlight for six hours after which a starch test was carried
out on the two leaves
(a) What were the results of the starch test on leaves X and Y? (2 marks)
(b) Give reasons for your answers in (a) above. (2 marks)
27. Why would carboxyhaemoglobin lead to death? (2 marks)
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 NYERI CENTRAL
BIOLOGY THEORY
PAPER 2
231/2
SECTION A
1. The diagram below a represents a transport tissue from a plant.

(i) Identify the tissue shown above. (1mk)

(ii) State the function of the tissue (1mk)
(iii) How is the tissue named in (i) above adapted to its functions. (3mks)
(iv) Name the forces involved in the movement of water and mineral salts up the plant. (3mks)
2. Study the food web below and answer the questions that follow.

(a) Construct a food chain where snakes are tertiary consumers. (1mk)
(b) Name two organisms that are in the second trophic level (2mks)
(c) State three effects on the ecosystem that may result if lions invade the ecosystem (3mks)
(d) Identify the organism with least biomas in the above ecosystem. (1mk)
(e) Name the process by which energy from the sun enters into the organisms. (1mk)
3. Glucose solution was boiled and cooled to 300 c and used in the experimental set-up below.

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(a) Explain the importance of the following procedures
(i) Boiling of the glucose solution. (1mk)
(ii) Cooling of glucose solution to 300c (1mk)
(iii) Covering glucose and yeast suspension with a layer of oil. (1mk)
(iv) How would you set a control experiment. (1mk)
(b) What observation were made in the following ;
(i) Thermometer (1mk)
(ii) Lime water (1mk)
(iii) Account for the observation in (b) (ii) above (2mks)
4. The diagram below illustrate some forms of beaks in birds

(a) Which diagram represents the beak which the others are likely to have evolved? (1mk)
(b) Explain your answer in (a)above (3mks)
(c) (i) What is a fossil (1mk)
(ii) Name two methods of fossil formation (2mks)
(d) Name one vestigial structure in human beings. (1mk)
5. Below is the internal structure of maize seed.

(a) Name parts labelled C , G (2mks)

(b) State the functions of the part labelled D. (1mk)
(c) (i) Which part develop into shoot and root on germination. (2mks)
(ii) What group of enzymes are present in part B (2mks)
(d) The maize seed is an endospermic seed. Explain. (1mk)
SECTION B
Answer questions 6 compulsory and either question 7 or 8

6. The glucose level in mg per 100cm3 of blood was determined in two persons Y and Z. Both had
stayed for 6 hours without taking food. They were fed on an equal amount of glucose at the start
of experiment. The amount of glucose in their blood was determined at intervals. The results are
shown in the table below.

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 Time in minutes Glucose level in blood mg/100cm3
Y Z
0 85 78
20 105 110
30 116 130
45 130 170
60 100 195
80 93 190
100 90 140
120 90 130
140 88 120

(a) On the grid provided plot graphs of glucose level in blood against time on the same axes.
(b) What was the concentration of glucose in the blood of Y and Z at the 50th minute? (2mks)
(c) Account for the level of glucose in person Y
(i) During the first 45 minutes (2 mks)
(ii) After 45th minute to the end (4mks)
(d) Account for the decrease in glucose level in person Z after 60 minutes (2mks)
(e) Low blood sugar level is harmful to the body. Explain (3mks)
7. (a) Describe the process of fertilization in a flowering plant. (15mks)
(b) Explain features and mechanism that hinder self pollination and fertilization. under the
Following:
(i) Protandry and protogyny (3mks)
(ii) Heterostyly (2mks)
(8) Describe how human kidneys function (20mks)

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 NYERI CENTRAL
231/3
PAPER 3
PRACTICAL
TIME: 1 ¾ HOURS
1. You are provided with a large potato, two unknown solutions labeled K1 and K2. An empty
petri dish labeled K3 ,cork borer and a ruler.
• Cut two opposite ends of the potato to have two flat ends
• Using a cork borer, obtain six cylinders from the potato measuring 3cm each.
• Place two potato cylinders in liquid K1 in a beaker,place the other two cylinders in liquid K2 in
a beaker and the last two cylinders in empty petri dish k3
• Allow the cylinders to remain the liquids and in the petri dish for 30 minutes
a. I) Remove each of the cylinders from liquid K1 and K2. feel the texture of each of the cylinders
by pressing gently between your fingers .
Note down your observations
Cylinders in liquid K1 (1mark)
Cylinders in liquid K2 (1mark)
II) Account for your observations in a (i) above
Cylinders in liquid K1 (2mark)
Cylinders in liquid K2 (2mark)
b. i. measure the length of each potato cylinder from the three set ups. Record original and final
lengths and complete the table below (3mks)
Original length (cm) Final length (cm)
Cylinders in liquid K1
Cylinders in liquid K2
Cylinders in liquid K3

II. Account for results in

Cylinders in liquid K1 (2mks)
Cylinders in liquid K2 (2mks)
Cylinders in liquid K3 (1mk)
c. i. What observations would be made if potato cylinders had been placed in boiling water for 5
minutes before being placed in liquid K1 and K2 (1mk)
ii. Give a reason for your answer in c (i) above (1mk)
d) what was the role of the cylinder placed in petri dish (1mk)
2. Study the photographs below depicting plants growing in different habitats. Use them to answer
the questions that follow.

Y z

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 T

a) Identify the habitats in which they are found. Y,Z and T (3 marks)
b) State the significance of the following structures found in the specimens shown above. R,S
(2 marks)
c) State two structural adaptations expected in the leaf of specimen Z. (2 marks)
d) State one observable adaptation in specimen for the habitat in which it is found. (1 mark)
e) Explain the effect of releasing too much waste containing fertilizer nutrients. (2 marks)
3. Below is a representation of the circulatory system of a certain animal

a) With reference to the diagram, classify animal into the following taxa.
i) Kingdom (1mk)
ii) Phylum (1mark)
Reason (2marks)
iii) Class (1mark)
Reason (2marks)
b) Name the parts labelledM,N,O and P (4marks)
c) i) State the type of circulation present in fish shown above (1mark)
ii) Give a reason for your answer (1mark)

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 NYERI CENTRAL
231
PAPER 1
2 HOURS
1. (a) B- Oviduct E-Vagina
(b) Oestrogen/progesterone
(c) B-Conducts ova produced to uterus
C-Site for implantation and development of foetus
2. (a) To allow light pass through so that cell structures can be seen.
(b) To avoid drying up of cells
(c) To make cell structures appear clear and distinct.
3. (i) Counter current flow system
(ii) Creates a steep concentration gradient for efficient gaseous exchange.
4. (a) X and Y (b) X
5. (a) The plancenta produces progesterone hormone which maintains pregnancy.
(b) Outside the body is slightly cooler conducive for the formation of sperms.
6. - Thicker inner wall and thin outer wall to allow differential expansion
- Contains chloroplasts to carry out photosynthesis and form glucose that alters osmotic
pressure of guard cells.
- they are bean shaped and face one another to form a pore.
7. (a) Contain lytic enzymes that kill and destroy worn out cell orgalles even entire cell.
(b) Site for respiration to produce energy for a cell.
8. Cytoplasmic streaming
9. (a) Diffusion
(b) Molecules of smelly gas freely move by diffusion from the carcass.
Environmental temperatures at midday rises and increase energy content in molecules
which cause molecules to move faster, hence more molecules spread leading to stronger
smell.
10. Plants absorb water from soil using root hair cells
- Controlling opening and closing of stomata
- Feeding in infectiourous plants
- Leads to support in herbaceous plant/non woody stem.
11. (a) Both alleles are expressed/shown equally in the phenotype of the offspring/none suppress
the other gene and black fur colour from expressing itself in the phenotype.
(b)
13. (a) Scurvy
(b) When blood glucose falls below normal
14. (a) Digestion is the breakdown of complex substances to simpler compounds which can be
absorbed.
(b) (i) Metallic ions e.g. iron, magnesium, zinc and calcium and ions
(ii) Vitamin D
Vitamin K
15. 1(a) Simple leaf……..Go to 2
1(b) Compound leaf…….C
2(a) Leaf with parallel venation……………B
2(b) Leaf with network venation…………….A
16. -To bring together living organisms with similar characteristics but separates the ones
with differ features.
-Helps in placing living organism into their correct groups for reference
-helps to arrange information in an orderly manner
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 -help to understand the evolutionary relationships between differ organisms
b) Species
17. -Enables termites to seek favourable habitat away from light so as to avoid predation and
dehydration.
18. (a) thigmotrophism/haptotrophism
(b) Auxins migrate away from the point of contact; less auxins causes less
elongation leading to less growth; the side far away from point of contact has higher
concentration of auxins leading to more elongation hence more growth and the stem
curves/twines along the supporting structrure.
19. (i) Arthropoda
(ii) -Has jointed appendages
-Presence of exoskeleton
-Body is divided into head, thorax and abdomen hence segmented
-Has spiracles hence gaseous exchange is through trachea system.
20. Cerebrum/cerebral hemisphere/cerebra cortex
21. B-Cerebrum C-Cerebellum D-Medulla oblongata
b) i) It controls learning, imagination, thinking, personality, hearing, vision and taste.
ii) It controls voluntary body movements/controls contraction of skeletal muscles e.g.
walking, dancing, movement of lips/chewing, movement of the neck/nodding and
movement sideways.
22. (a) Diabetes Inspidus
(b) Antidiuretic hormone/vasopressin
23. - Swallow plenty of sea water to increase amount of water in the body.
- Have chloride secretory cells in the gills to remove excess salts
- Eliminate nitrogenous wastes in form of trimethylamine oxide which requires little water
for elimination.
- Few/small glomeruli: thus slow filtration rate in the kidneys.
24.
a) - Their walls are made up of an endothelium only which allows part of blood to move into
the intercellular space.
- Have narrow lumen that maintains high blood pressure
- They are numerous thus creating a large surface area for exchange of materials.
(b) (i) Red blood cells
(ii) Oxygen
(c) (i) Leucocyte/white blood cell/phagocyte
(ii) It is migrating from a capillary to the tissue fluid by squeezing between capillary
endothelial cells.
25. - Lacks chloroplasts making it transparent to allow light to pass and reach the photosynthetic
cells.
- Has stomata which allow entry of carbon (IV) oxide and exit of oxygen.
26. (a) X- Iodine solution turned blue black hence presence of starch
Y-Iodine solution retains its yellow brown colour hence absence of starch.
(b) X-acts as a control where all requirements are present
Y-Carbon (IV) Oxide (CO2) is absent. It is absorbed by potassium hydroxide pellets
hence the rate of photosynthesis could not take place.
27. Carboxyhaemoglobin is a very stable compound that does not easily dissociate; therefore
reduces the capacity of haemoglobin to transport oxygen to the tissues.

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 NYERI CENTRAL
PAPER 2
MARKING SCHEME
SECTION A
1. i) xylem
ii) Conduct water and mineral salts from the soil to leaves
iii) Have narrow lumen to enhance capillarity
- Hollow to allow continuous flow of water
- Lignified walls to prevent collapse of walls
- Has side pits to access lateral movement of water and mineral salts.
iv) Transpiration pull
- Capillarity
- Adhesion and cohesion force
- Root pressure
2. a) Green plants → grasshoppers → lizard → snake.
b) Gazelle, rat, grasshopper
c) Gazelle population will decrease
- Green plants will increase
- Rats and grasshopper population increase
d) Hawk
e) Photosynthesis
3. a) i) To expel/remove all air to ensure no oxygen
ii) To avoid denaturing /killing of enzymes in yeast cells
iii) To prevent entry of air
iv) Using boiled yeast
b) i) Temperature rises/increases
ii) White precipitate is formed
iii)- Anaerobic respiration produces co2 which reacts with lime water to form white precipitate of
calcium carbonate
- Anaerobic respiration produces heat energy.
4. a) M
(b) Beak M is simpler/basic hence likely to be original beak. The birds separated to occupy different
niche and specialized for different diets. This led to more complex/shape, length & size of beak.
c) i) preserved remains of ancestral forms of organisms that lived in ancient times in natural
occurring materials e.g sedimentary rocks.
ii) Petrification
- Formation of moulds, imprints and casts (impressions)
- Presemation of entire organims plant resins or ice
d) 1. Appendix
2. Coccyx/Human tail/
3. Ear muscles
4. Nictating membrane.
5. C-Cotyledon
G-Coleorhizae/radical sheath
(b) Protects the plumule especially during germination.
(c) shoot-E
Root-F
(ii) –Carbohydrases
- proteases
- Lipases
(d) The maize seed stores food in the endosperm rather than the cotyledon.

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6) (a)

(b) Y-120mg/100cm3 +1
Z-178 mg/100cm3 +1
(c) i) Blood sugar level increased to 130mg/100cm3 –Glucose is being absorbed from the intestines.
Some of it by-passes the liver without entering the cells thus raising blood glucose level.
(ii) Glucose concentration reduced to normal (90mg/100cm3). High blood glucose stimulates the
pancrease to produce insulin, which stimulates the liver cells to take up glucose and convert it into
glycogen.
(d) Some of the glucose is used in respiration to generate energy; while some lost in urine;
(e) Glucose is the raw material for respiration; A low level of glucose leads to lowered respiration;
hence less energy available in the body;
7. (a) pollen grains land onto stigma and adhere to it as a result the stigma cells secret a sticky substance.
It absorbs nutrients and germinates forming a pollen tube which grows down the style to ovary,
deriving nourishment from surrounding tissue. The pollen tube has tube nucleus at the tip and
generate nucleus immediately behind it as the tube grows downward into the ovary the generative
nucleus divides by mitosis to give rise to two male nucle, which represent the male gameto. The
pollen tube penetrate the ovule/embryo sac through micropyle. After the pollen tube enters the
embryo sac the tube nucleus breaks down/degenerate, leaving a clear passage for the entry of male
nucle, then enter into the embryo. The other male nuclei fuse with the two polar nuclei to form
trploid nucleus which become endosperm.

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(b) (i) protandary and orotagyny;
Some flowers have male or female reproductive parts repening at different times. Protandary;
condition in which the stamens ripen/mature before the stigma of the same flower or other flowers in
some plants are mature enough to receive them e.g sunflower protogyny; condition in which stigma
mature earlier and ready to receive pollen grains before anthers of same flower are ripe enough to
shed pollen grains e.g maize.
(ii) Heterostyly;
A structural feature of a flower due to variation in length of the style in relation to stigma. It is either
short stamen and a long style giving stigma a position at flowers mouth or short style and a long
stamen to opening the flower. Insect will find it difficult to deposit pollen grains received from one
flower type to stigmas of other type e.g oxalls, flax
8. Describe how kidneys function.
Kidneys receive blood from renal artery, a branch of dorsal aorta, hence blood is under high
pressure. The afferent arteriole which is the branch of renal artery supplies blood to glomerulus;
- The afferent arteriole has a wider diameter than the efferent arteriole; this causes back resistance
Hence high pressure in the glomerulus leading to ultra-filtration. The walls/capsular barriers are one
Cell thick hence glucose, amino acids, vitamins, hormones, salts, (creatinine) urea and water filter
Into Bownwa’s capsule to form glomerular filtrate; white blood cells/red blood cells and plasma
Proteins such as (Globulin, fibrinogen, platelets) are too large to pass through the capillaries; the
Filtrate flows into the proximal convoluted tubule, where all amino acids, vitamins and all glucose
Are selectively reabsorbed back into the blood stream by active transport. There are many
mitochondria to provide energy for re-absoption of these substances against concentration gradient
By active transport. The glomerular filtrate flow into loop of Hnie. Water in descending loop
Moves by osmosis into the blood capillaries; sodium, chloride is actively pumped from the
ascending limb of loop of Henle into the blood capillaries with the help of aidosterone hormone.
Produced by adrenal gland. The glomerular filtrate flow into the distal convoluted tubule, water is
Re-absorbed from distal convoluted tubule into blood capillaries; the glomerular filtrate flows into
Collection tube/duct from where more water is reabsorbed into blood stream. Antidiuretic hormone
influences the amount of water reabsorbed depending on osmotic pressure of blood; the
Glomerular filtrate from collecting duct no referred to as urine; is emptied into pelvis. The urine
Passes though pelvis and ureter into urinary bladder out of the body through urethra when sphincter
Muscles relax.

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 NYERI CENTRAL
PAPER 3
MARKING SCHEME
1.
I) Cylinders in liquid K1 _____feels soft
Cylinders in liquid K2
Feels firm/hard/rigid/Stiff (1mk)
II) Account for your observations in a (i) above
Cylinders in liquid K1the liquid is hypertonic ,than the cell sap of the potato cells, the cells lose
water by osmosis, shrink and become plasmolysed (2mk)
Cylinders in liquid K2 the liquid is hypotonic to the cell sap of the potato cells, the cells draw
water by osmosis becoming turgid (2mk)
a. i. measure the length of each potato cylinder from the three set ups. Record original and final
lengths and complete the table below (3mks)
Original length (cm) Final length (cm)
Cylinders in liquid K1 3 2.7 (must decrease)
Cylinders in liquid K2 3 3.5 (must increase)
Cylinders in liquid K3 3 3 must remain constant
II. Account for results in
Cylinders in liquid K1
Liquid is hypertonic to cell sap of potato cells. the cells lost water by osmosis becoming flaccid
thus reducing in length (2mks)
Cylinders in liquid K2
Liquid is hypotonic to cell sap of potato cells. the cells gained water by osmosis becoming
flaccid thus increasing in length (2mks)
Cylinders in liquid K3 no change in length as no physiological process took place(1mk)
c. i. What observations would be made if potato cylinders had been placed in boiling water for
5 minutes before being placed in liquid K1 and K2 (1mk) the lengths of potato does not
change
ii. Give a reason for your answer in c (i) above boiling denature cells hindering osmosis
d) What was the role of the cylinder placed in petri dish control experiment 1mk)
2. a. Identify the habitats in which they are found. (3 marks)
Y _________fresh water accptaquacticZ_dry/desert /semi desert
T saline/salty/marine
3. State the significance of the following structures found in the specimens shown above.
R discourage herbivores from feeding on it/ rej prevent
S Encourage buoyancy/floating of plants
4. State two structural adaptations expected in the leaf of specimen Z. (2 marks)
Small sized/hairly leaves
Small/sunken stomata/hairy stomata/more stomata on lower epidermis
Nb; mark point on stomata only
5. State one observable adaptation in specimen for the habitat in which it is found. (1 mark)
Has pneumatophores/ breathing roots (that grow outward to the atmosphere to trap more
oxygen)
6. Explain the effect of releasing too much waste containing fertilizer nutrients. (2 marks)
Leads to increase in phosphates and nitrates in water; water plants bloom/ excessive growth
deplete 3dissolved oxygen in water, they die, dead decomposed plants float in water surface
limiting light penetration hence photosynthesis of submerged plants which are primary
producers; decomposition further deplete oxygen therefore eutrophication hence loss of aquatic
life and masses
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3. Below is a representation of the circulatory system in Fish.
a) With reference to the diagram, classify fish into the following taxa.
i) Kingdom (1mark)
Animalia;
ii) Phylum (1mark)
Chordata;
Reason (2marks)
Closed circulatory system;
iii) Class (1mark)
Pisces;
Reason (2marks)
Two chambered heart;
Single circulation;
b) Name the parts labelledM,N,O and P (4marks)
M- Gill capillaries;
N- Atrium / Auricle;
O- Ventricle;
P- Artery;
c) (i) State the type of circulation present in fish shown above (1mark)
Single circulation.
(ii) Give a reason for your answer (1mark)
Blood passes through the heart once for every complete cycle;

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 IGEMBE CENTRAL
231/1
Paper 1
(Theory)
Time 2 hours
1. Study the diagram below showing a portion of an onion epidermis that had been irrigated with a
certain solution X

a) In one word describe the condition of the cells. (1 mark)

b) Describe the process that led to the condition named above. (2 marks)
2. The following reaction may proceed in forward or backward direction.
Glucose + fructose Sucrose + water
a) What term is used to refer to the backward reaction. (1 mark)
b) In which part of alimentary canal does the backward reaction occur? (1 mark)
c) Name the enzyme that catalyzes the backward reaction. (1 mark
3. The diagram shown below represents nucleus

a) State the role of the organelle labelled Q (1 mark)

b) Name a kingdom whose members lack structure labelled P (1 mark)
c) Which is the general term given to organisms whose cells have structure P (1 mark)
4. A fertilization of an ovule, which parts develops into
a) Testa (1 mark)
b) Endosperm (1 mark)
5. a) Explain two roles of diffusion in human beings. (2 marks)
b) i) Name this process through which a plant takes up some mineral ions against a concentration
gradient. (1 mark)
ii) State two factors that may affect the process named in b(i) above (2 marks)
c) Distinguish between haemolysis and plasmolysis (1 mark)
6. An insect landed on a leaf of an insectivorous plant. Consequently, the leaf closed with its spines
interlocking trapping the insect inside it. Name the response exhibited by the leaf. (1 mark)
7. The figure below represents a plant

a) State the division it belongs to (1 mark)

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b) Label the parts labelled a, b (1 mark)
c) State the role of part labelled d in the life cycle of the organism (1 mark)
8. State any two adaptations of the cardiac muscle that enable it to undergo systole. (2 marks)
9. a) Why are carbohydrates and not lipids the first choice respiratory substrates? (2 marks)
b) 2C57H110O6163O2 ® 114CO2 + 110H2O + Energy.
Calculate the RQ from the equation in ( c ) above. (2 marks)
10. Below is a diagram of a group of cells of a specific tissue.

i) Name the tissue (1 mark)

ii) This tissue lines the trachea and bronchi. Suggest its function in these structures. (1 mark)
11. Study the flow chart below which represents a physiological process in mammals.
Prothrombin X

Y Thromboplastin

Thrombin

Fibrinogen Z

a) i) Name blood components represented by X. (1 mark)

ii) What is the significance of product represented by Z (2 marks)
b) Under what condition is thrombokinase released by the platelets. (1 mark)
12. a) Explain what happens to excess amino acids in the liver of humans (2 marks)
b) Which portions of the human nephron are only found in the cortex? (1 mark)
13. A potted plant is transferred from outside on a sunny and windy day, to a dark room
a) Briefly explain the effect this is likely to have on:
i) The rate of loss of water from its leaves (2 marks)
ii) The rate of water absorption (1 mark)
14. Give a reason why urine of a mammal does not contain amino acids. (1 mark)
15. a) In what form is energy stored in muscles? (1 mark)
b) State the role of insulin in human body. (1 mark)
16. Name the processes that take place in the liver to bring about differences between blood in the
Hepatic portal vein and that in the hepatic vein (2 marks)
17. The graph below shows how the body temperature of a toad and man varies with time in hours.
Study it answer the questions that follow.
40
Temp °C

30
Toad
20
Air
10

0
7 11 3 7 3 7
am am pm pm am am
Time in hours
a) What is the relationship between the body temperature of the toad and that of the atmospheric air?

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b) State two corrective measures that maintains man’s body temperature at norm even when the
environmental temperature is below 30°C (2 marks)
c) Give one behavioural adaptation observed in a lizard when the environmental temperature is above
39°C (1 mark)
18. The figure below shows the exposed breathing apparatus of a fish.

a) Name the structure that was removed to expose the apparatus. (1 mark)
b) i) Name the structure P (1 mark)
ii) State two structural adaptations of the respiratory surface in insects. (2 marks)
19. The following is a reproductive structure of a plant.

B
a) Identify the structure (1 mark)
b) Name the sub-division of the plants that produces the above reproductive structure. (1 mark)
c) i) Name structure B (1 mark)
ii) What is the function of structure A? (1 mark)
20. Nucleic acid are made up of nucleotides that bears a sugar component
a) Name the sugar component found in (2 marks)
i) DNA fragment
ii) RNA fragment………………………………
b) The following nucleotide sequence was found in segment of DNA. AGCCT . Write down the
complementary base sequence in the corresponding m RNA segment during transcription.
c) A point mutation altered the base sequence from the original to G G C C T. Identify the type of gene
mutation (1 mark)
21. Below is a drawing of a cell.
X Y
skeletal
muscle

a) With two reasons, identify the cell. (2 marks)

b) Which of the three structure X, Y and Z speeds up transmission of the impulse. (1 mark)
22. a) Name the pigment that protects human from the negative effect of Ultraviolet lights
b) Explain how sunlight contributes to stronger bones and teeth in human beings. (1 mark)
c) i) State one structural differences between skeletal muscles and smooth muscles (1 mark)
ii) What are antagonistic muscles? (1 mark)
23. Name the substrates for the following enzymes
i) Carbonic anhydrase. (1 mark)
ii) Cholinesterase (1 mark)
24. A tilapia fish has a full length of 300mm but measures 200mm from the mouth tip to its anus.
Determine the tail power of the fish. (1 mark)

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25. State the differences between cones and rods in terms of the following (2 marks)
26. Impulse transmission across a synapse is in one direction. Explain (2 marks)
27. The diagram shown below represents a section of the vertebral column

T S

a) Name the part labelled S (1 mark)

b) State TWO ways in which part T is important to movement in human beings. (2 marks)
28. Give TWO features that make modern man to be more adaptable to the environment.(2 marks)

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 IGEMBE CENTRAL
231/2
Paper 2
(Theory)
SECTION A : (40 marks)
1. The flow chart below shows a process in plant and animal cell
Glucose

Process X

Product A + 2ATP

Anaerobic Aerobic respiration

respiration krebs cycle electron transport
chain (36 ATPS)

Fermentation in Fermentation
animal cell plant, yeast

Product B + 2ATP Product C + D +

2ATP + heat

a) Why is this process necessary in living organisms (4 marks)

b) i) Name the process labelled X (1 mark)
ii) Name the part of the cell where process X occurs (1 mark)
c) Name products A, B(2 marks)
2. a) The bar charts show the percentages of a human population with each type of blood group
and the percentages of a cattle population with and without horns.
80 80 without
horns
% population

60
% population

60

40 40
Group Group Group Group with
20 A O 20 horns
B AB
0 0
human blood groups cattle

Which type of variation is shown in each populations? (1 mark)

Human
Cattle
b) Albinism (lack of skin pigmentation) in humans is caused by two recessive alleles. A
phenotypically normal (non-albino) couple have three children ; the first two are non-albino, the
third is an albino. In your answer, use ‘A’ for the dominant allele and ‘a’ for the recessive allele.
i) What are the genotypes of the parents? (1 mark)
ii) Is there a possibility that their next child will be an albino? Explain your answer. (2 marks)
iii) The albino child eventually marries a non-albino whose father was an albino. What is the
probability that their first child will be an albino? Show all working. (4 marks)

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3. The diagram below shows structures of the bat wing and human arm.
Human Bat

These structures are thought to have same ancestral origin

a) State one structural similarity and one adaptation difference between the two.
i) Structural similarity. (1 mark)
ii) Adaptation difference (2 marks)
b) Give two other examples of structures in nature that show the type of evolution as in (a) above.
c) Distinguish between the terms ‘chemical evolution’ and ‘organic evolution’ (2 marks)
d) What is the study of fossils called? (1 mark)
4. The diagram below shows structures of gaseous exchange system in man

P
K

a) Name the structure labelled K (1 mark)

b) Structure labelled L is lined with two cells name these two cells (2 marks)
c) Explain the function of these two cells identified in 4(b) above in the structure labelled L
d) Explain how oxygen moves from P to Q (2 marks)
e) Tobacco smoke affects gaseous exchange system name the component of the tobacco that
affects this gaseous exchange system (1 mark)
5. The diagram below shows a scanning electron micrography of some pollen grains from insect
pollinated flowers and wind pollinated flowers.

a) With reasons identify the pollen grains that are from

i) insect pollinated flower (1 mark)
Reasons (2 marks)
ii) Wind pollinated flower (1 mark)
Reason (1 mark)
b) Write the formula that would be used to calculate the actual diameter of pollen grain H.
c) After pollination pollen grains germinate into pollen tubes. State two functions of pollen tube.
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 SECTION B
Answer two questions in this section question 6 is compulsory and choose either question 7 or 8
6. The table below shows the fresh weight and dry weight of maize plants at different stages of
growth.
Time in weeks 0 2 4 6 8 10 12 14 16
Fresh weight (g) 20 120 300 700 1000 1220 1500 1400 1100
Dry weight (g) 20 60 200 500 680 800 880 1000 1000
a) On the same axes, plot graphs of fresh and dry weighs against time. (8 marks)
b) Account for the shape of the curve of fresh weight between
i) 2—10 weeks. (2 marks)
ii) 12—16 weeks (2 marks)
c) Suggest why dry weight remains constant after week 14. (2 marks)
d) Describe how the dry weight of the maize could have been determined at various times.
e) State two advantages and one disadvantage of fresh weight as a measure of growth.
7. Describe how the leaves of mesophyte are suited to their function. (20 marks)
8. a) Explain how the osmotic pressure in human blood is maintained at a normal level.
(5 marks)
b) Describe the role of human skin in homeostasis. (15 marks)

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 IGEMBE CENTRAL
231/3
Paper 3
Practical
1¾ Hours
1. You are provided with Irish potato tuber labelled specimen K, use it to answer questions that
follow.
Cut out two cubes whose sides measure 1cm from the Irish potato provided.
Label three test-tubes as A, B and C and put them into the test-tube rack.
A) Crush one cube to obtain a paste and add about 15cm³ of distilled water to the paste to from a
solution and then carry out the following procedure;
i) Use a measuring cylinder to transfer 5cm³ of potato solution extract into testtube A
ii) Use the measuring cylinder to transfer 5cm³ of potato extract from test-tube A to test tube B.
iii) Use the measuring cylinder to add 5cm³ of distilled water to test-tube B. Place a stopper in test-
tube B and shake it.
iv) Remove the stopper. Use the measuring cylinder to transfer 50cm³ of the liquid in test-tube B to
test tube C.
v) Use the measuring cylinder to add 5cm³ of distilled water to test-tube C. Place a stopper in
testtube C and shake it. Using a measuring cylinder reduce the volume of solution C to 5cm³.
a) Table below shows the percentage concentration of the potato extract solution
Test-tube Percentage concentration of potato extract solution
A 100.00%
B
C

Complete the table above by calculating and writing in the percentage concentration of potato
extract solution in test-tube B and C (2 marks)
b) Using a measuring cylinder pour 1cm³ of Hydrogen peroxide to the content in test-tube A, B
and C and make the observation.
i) What was the aim of the investigation above. (1 mark)
ii) Write the word equation for the reaction taking place in test-tubes. (1 mark)
iii) What will be expected observation if the Irish potato was replaced with mammalian liver .
iv) Explain your answer in c(iii) above. (2 marks)
B. Crush the remaining cube to obtain the paste. Use the reagents provided to and carry out food
test on the extract. (4 marks)

2. You are provided with specimen labelled

T : Hibisius rosaninensis
K : Bougainvillea glabra
L : Jacaranda Mimosifolia
M : Alopecurus pratensis
N : Lantana camara
a) Using the characteristics given below and in the order in which they occur, Construct a
dichotomus key to identify the specimens. (8 marks)
1. type of leaf
2. leaf venation
3. leaf margin
4. texture of leaf lamina
b) i) Identify the likely habitat of the plant from which specimen labelled N was obtained from

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 (1 mark)
ii) Give a reason for your answer in b(i) above (1 mark)
c) i) Name the class of the plant from which specimen M belong (1 mark)
ii) Give a reason for your answer in c(i) above. (1 mark)
d) Study the photographs below depicting plants growing in different habitats.

i) Identify the habitats in which they are found Y, Z (2 marks)

ii) State the significance of the following structures found in the specimens shown above. R
3. The diagrams below represent body parts of some organisms (animals). Study them and answer
the questions that follow.
A B C

D E F

Suggest the type of food eaten by organisms with the part labelled A, B , C and F
ii) With reasons, suggest the likely habitat of the organism from which the part labelled D was
obtained (1 mark)
b) i) Suggest the type of evolution that is exemplified by the organism labelled D, E and F.
Give reason for your answer.
ii) Suggest the significance of the above named type of evolution for the organism.
b) i) Explain briefly the meaning of analogous structure. (1 mark)
ii) Give one example of analogous structure. (1 mark)

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 IGEMBE CENTRAL
231/1
Paper 1
(Theory)
Time 2 hours
1. a) flaccidity;
b) The cell sap was hypotonic to the solution X; hence water was drawn from the cell into the
solution by osmosis; making the cytoplasm to shrink and cell membrane detach from the cell
wall;
2. a) hydrolysis;
b) ileum;
c) sucrose;
3. a) to control all cell activities;
b) Monera; reject without capital M
c) Eukaryotes Acc Eukaryotic organisms
4. a) integuments;
b) primary endosperm nucleus;
5. a) absorption of digested food such as glucose and amino acids; into the blood stream;
- exchange of respiratory gases i.e. oxygen and carbon (IV) oxide between the alveolus and blood
capillaries.
- excretion of nitrogenous waste, such as urea; from the blood capillaries into elimination site;
b) i) active transport;
ii) Low oxygen concentration; - lowering temperatures below optimum level; presence of enzyme
c) Haemolysis—process by which animal cells take up water from a solution of lower solute
concentration by osmosis fil it burst; OWTTEE
- Plasmolysis—process by which plant cells loose water to a solution or higher. Solute concentration
by osmosis and become flaccid OWTTEE
6. Thigmonasty / haptonasty; rej positive thignomasty
7. a) Bryophyta; reject small letters
b) a) seta; b) capsule;
c) produces gametes whose fusion give rise to the sporophyte generation /c ;
8. i) Has a specialised region on the right atrium / pacemaker known as sinoatrial note; Rej SAN
- Has specialised muscle region at the boundary between atria and ventricle called atrio ventricular
node that spread the construction;
ii) Muscles cells are interconnected to enable; smeading of the wave of contractions;
9. They are easily transported to the respiratory site;
They require less oxygen for their oxidation;
b) RQ = carbon (IV) oxide produced; = 104CO2 = 0.669;
oxygen used 163O2
10. i) (Ciliated) epithelial tissue; Rej epithelial cell
ii) It wafts mucus with trapped dust/solid particles away from the lungs;
11. a) Platelets / thrombocytes ;
ii) Forms a clot that prevent excessive bleeding / prevent entry of pathogens / prevent anaemia;
b) when platelets are exposed to the air/when platelets clamp together and stick to the wall of
damaged blood vessel; OWTTE
12. - Excess aminoacids one deaminated in the liver; with formation of ammonia ; which reacts with
carbon (IV) oxide to form urea an excretory waste product.
b) Baoman’s capsule;
Proximal convoluted tubule;
Distal convoluted tubule; any one
13. a)
i) The rate of loss of water reduces; because temperature lowers an wind conditions reduced;

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- Rate of water absorption reduces; because rate is transpiration/water loss reduces hence loss water
needs to be replaced;
ii) Rate of water absorption reduces; because rate of transpiration / water loss reduces hence water
needs to be replaced;
14. All amino acids are reabsorbed in the proximal convoluted tubule/kidney nephron;
15. a) Adenosine triphosphate; Rej ATP
b) Insulin stimulates oxidation of glucose to release energy;
Insuline stimulates conversion of excess glucose into fats and glycogen
Insule inhibitor of production of glucagon hormone;
16. - deamination
- blood sugar regulation
- respiration
- detoxification; any two
17.
- The toads body's temperature fluctuates with the fluctuation of atmospheric air temperature;
b) Increased respiration to generate more heat;
- vasoconstriction thus less blood flowing to the skin reducing heat loss;
- contraction of electorpilli muscle, raising the hairs to trap a layer of air that insulate the body against
heat loss;
- shivering to generate heat;
- reduced or no sweating to reduce heat loss;
(Mark first two)
c) Moves to cooler place / more to shade;
Acc Aestration
18. a) Operculum;
b) i) Gill filament; Rej Gill filaments
ii) Are always moist for gases to dissolve and diffuse in solution;
- The (tracheoles) are branched to increase surface area for gaseous exchange;
- They have thin walls to reduce distance of diffusion of gases.
- Highly vascularised to mention a steep concentration gradient for maximum diffusion of respiratory
gases; Mark first two
19. a) Pollen grains; Rej pollen grains
b) Angiospermaphyta / Angiospermae / Angiospermatophyta; Rej with small letter
c) i) Generative nucleus;
ii) Directs the growth of pollen tube through the style towards the micropyle
20. i) Ocoxyribose sugar;
ii) Ribose sugar;
b) U-C-G-G-A;
c) Substitution;
21. a) Motor neurone;
Cell body found at the end of axon;
It is multipolar /from the cell body projects several denddrones;
- has effector dendrites that terminates at the muscles;
any one
b) Y; Acc node of or ranvier
22. Melanin;
b) Formation of vitamin D ; responsible for absorption of calcium and phosphate; any one

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c) i)
Skeletal muscle Smooth muscle
i) - attache to the skeleton striated / striped - found in lining of visceral organs
unstriated /unstripped
ii) - Multinucleated Mono nucleated;
- voluntary Involuntary:
- fatigue easily Fatigue;
ii) Muscles that work as pair; when one contracts the other one relaxes for cause movement ;
e.g Bisecpts and tricepts
23. i) carbonic acid;
ii) acetyl chlorine;
24. Tall power = length from tail tip to the ans
length of tall tip to the month
= 200 x 100 = 66.667%
300
25.
Feature Cone Rod
Visual acuity High; Low;
photochemical Iodopsin; phodopsin
26. - impulses one transmitted from presynaptic knob to the port
- Synaptic knob; through synaptic cleft aided by Neurotransmitter chemical acetylcholine;
27. a) Neurospine;
b) made of cartilage that allows gliding movement;
reduces friction;
Acts as a shock absorber;
First two
28. - Bipedal limbs for movement;
- Has opposable thump formation and stability
- cranium with a high brain-capacity;
- has a well developed speech;
(mark first two

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 IGEMBE CENTRAL
231/2
Paper 2
(Theory)
Time 2 hours
1. Respiration leads to production of energy which is essential for the following body activities;
Muscular contraction to bring about movement ü conduction of nerve impulses ü secretion of
enzymes, hormones, mucus etc growth and repair of worn out tisses functioning of the body organs
e.g. kidneys, heart, brain. max 4 marks
b) Glycolysis
ii) cytoplasm
c) A Pyruvic acid
B Lactic acid ü
2.a) Human—Discontinuous variation
Cattle—discontinuous variation
b) i) Both Aa
ii) Yes; the chance of them getting an albino child is 0.25 or 25%
3.
a) i) both are pentadactyl limb / the end in 5 digits
ii) one is adapted for gasping thing ü and the other one is adapted for flyingü
b) Beaks of bird
Feet of birds
c) Chemical evolution is view of origin of life that supposes that life began through catalytic effect of
lightening or other catalys it that brought elements together to form simple molecules that formed
compounds and latter complex self replicating molecules; organic evolution a process where present
life forms gradually arose from simple life forms over a long period of time
d) Paleontology
4. a) Broncioleü Rej Brochotes.
b) Goblet ü
Ciliated cell
c) Goblet cells secrets ü (mucus that trap dust and other solid particles in the inhaled air)
Ciliated cell
d) There is more oxygen in structure labelled P that in Q it moves by diffusion in Q
e) nicotine / tar
5. i) J
Large with pricky hairs to stick on the body of the insect
H—Small and smooth to be easily carried by wind
b) Drawing length of H = Actual length of H
magnification
c) Offer passage through which male nuclei pass through to reach the embryo sac to enhance
fertilization
Secretes enzymes that digest tissues of the style ovary
SECTION B
6 a)
b) i) Rapid increase in fresh weight / very rapid growth plants absorb water and nutrients from the
soil and use them for growth
ii) Fresh weight decreases due to loss of water drying up of the plant since the plants have matured
c) The plant has matured / cells have died hence there is no further growth
d) By uprooting the plants ü removing all the soil dry them) in an oven at 110 degrees Celsius) remove
the plants in over at intervals and reweigh them till a constant weight is obtained
OWTTE
e) Advantage

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 The plant are not killed thus their growth can be monitored
Disadvantages
Fresh weight is influenced by water content hence it does not give actual biomass
7. The main functions of the leaves is gaseous exchange; photosynthesis and transpiration
Has broad and flat lamina to increase surface area to trap maximum light for photosynthesis ü and
provide a large surface area for gaseous exchange
- Have a thin lamina ü to reduce distance for diffusin gases ü and also for maximum penetration of
light to reach photosynthetic tissues
- Cuticle and epidermis are transparent to allow light pass through
- The epidermis is thin to reduce the diffusion distance for the gases the easier penetration of light to
photosynthetic tissues
- Have palisade cells the numerous chloroplast below the upper epidermis for maximum trapping of
light
- Have veins which contain vascular bundles ü which transport water and mineral salts ü to the
photosynthetic cells and translocate manufactured food from photosynthetic tissues
- Have stomata which allow diffusion of gases in and out the leaf
- Have guard cells ü which control the opening and closing of the stomata hence regulating water loss
from the leaf.
- Spongy mesophyll cells are irregular arrange creating large air space for circulation of gases within
the leaf;

8. Normal osmotic pressure of blood is maintained by the kidney and neuroendocrine system; when the
osmotic pressure rises osmotic receptors in the hypothalamus detect; the pituitary gland is stimulated
to secrete anti diuretic hormone; which is carried through the blood to the kidney where it increases
the permeability of distal convoluted tubule collecting tubule and blood capillaries to water; water is
reabsorbed from the filtrate ; leading to production of little concentrated urine lowering osmatic
pressure of blood back to normal; When there is too much ions in the blood adrenal cortex; respond
by secreting less aldosterone; which causes less ions to be absorbed; from the gut into the blood
lowering the osmotic pressure to normal;
Accept converse (5 marks)
b) Human skin plays a role in thermal regulation and salt and water balance ü
External temperature changes affecting the body are determined by thermoreceptors in the skin;
The send the impulse; to the hypothalamus; once the temperature changes are detected; they send
impulse to appropriate tissues of the skin; to respond accordingly;. When body temperature rises
above normal;
The sweat glad in the skin secrete sweat; that absorb heat;
Superficial arteries; vasodilate; bringing more blood to the surface to the skin increasing heat loss;
Ecrectopilli muscle relax; causing hair to lie flat; trapping less air; increasing heat loss; lowering the
temperature to the normal.
15 marks
Accept the converse

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 IGEMBE CENTRAL
231/3
BIOLOGY
Paper 3
1.
Test-tube Percentage concentration of potato extract solution
A 100.00 %
B 50.00%
C 25.00%
b)
Test-tube Observation
A A lot / more / high amount of effervescence / bubbles
B Moderate / average amount of bubbles / effervescence;
C Little / few /small amount of effervescence / bubble;
i) to determine the effect of catalase (enzyme) concentration on the rate of reaction / oxygen
production.
ii) Hydrogen peroxide → water + oxygen;
iii) More effervescence / bubbles produced, when a liver was used as compared to when Irish potato
was used
iv) Liver is an animal excretory organ; liver has high concentration of catalase enzymes to break down
high level of toxic hydrogen peroxide produced in the liver.
b)
Test Procedure Observations Conclusions
Starch. ReJ: To 2ml of food substance/potato extract The colour changes to Starch;
iodine test (solution). Add 2 drops of iodine solution blue-black;
and shake
Rej: Iodine alone
Rej: two to three drops;
Reducing To 2ml of food substance/potato extract The colour of Reducing sugars
sugar. (solution) add equal amount of Benedit’s Benedict’s solution is absent;
Rej: Benedit’s solution and heat to boil; retained / remain
test
3. 1. a) Leaf simple . . . . . .go to 2
b) leaf compound . . . .Jacaranda mimosifolia
2. a) leaf parallel veined . . . . Alopecurus pratensis
b) leaf net veined / reticulate /branched . . . . go to 3
3. a) leaf margin smooth/entire . . . . bougainvillea glabra
b) leaf margin serrated /teeth like/dentate . . . . . go to 4
4. a) Lamina texture rough / hairy . . . . . lantana camara
b) lamina texture smooth . . . . . (T) Hibiscus rosaninensis.
Conditions for scoring.
1. Reject step two if written without veins or venation
2. Accept if the candidate use letters or name of specimen.
3. In case there is a wrong identity e.g the student has written leaf simple e.g go to 3 any wrong step
spoils subsequent step.
4. Reject a complete line/a line with arrow
5. Reject if steps not well labelled e.g. 1 without (a) and (b)
Reject step written in romans.
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b) i) Terrestrial ;
ii) Hairy cuticle that prevent excessive transpiration;
c) i) Monocotyledonae; Rej if M is small letter.
ii) parallel veined;
d) i) Thorns protect the plant from being fed by animals;
ii) Y—Aquatic
Z—Arid/semi-arid areas
a) i)
Food Reason
A Nectar; Long thin/slender beak for probing into the follower to suck nectar;
B Grains/cereals / seeds; Strong beak for cracking seeds;
C Pond water/water weeds; Flat serrate for filtering food from the water;
D Fresh/meat; Pointed claws for seizing prey;
ii)
Part Habitat Reason
D Aquatic Webbed feet for swimming;
b) i) Divergent evolution
Reason: They have common embryonic origin but adapted to perform different, functions; a
phenomenon known as adaptive radiation;
ii) Enhances the organism to occupy different ecological niches;
b) i) are structures that have different embryonic origin but have evolved to perform similar
functions; due to exploitation of the same kind of environment.
ii) wings in birds having the pentadactyl structures while insects the wings have veins composed
of cuticle.

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 MURANGA SOUTH
231/1
Paper 1
Time: 2 hours
Answer all the questions in the spaces provided.
1. Name any two branches of microbiology. (2marks)
2. Which biological tool would a scientist require to collect rats to be used for study?
3. When are two organisms considered to belong to the same species (2marks)
4. The diagram below represents an organism

a) Name the kingdom to which the organism belongs. (1mark)

b) Suggest the habitat in which the organism lives. (1mark)
c) Give two reasons for your answer. (2marks)
5. State two unique characteristics of Chordate not found in another Phylum. (2marks)
6. Shieko sec school biology student used a microscope with X40 objective lens and X5 eye piece
lens which had 2mm radius. Calculate the area of the field of view in micrometers.
b) What is the average size of the cell in micrometers if there were 5 cells on the field of view
(2marks)
7. The cells shown below were obtained from two different plant cells which were immersed in
2% and 25% salt solutions

8. a)Which of the two cells A and B was immersed in 2% salt solution? (1mark)
b) Comment on the nature of 25% salt solution in relation to the cell sap. (1mark)
c) What biological phenomenon leads to the observation made in A. (1mark)
9.
a) If pepsinogen and trypsinogen were produced in their active forms, what would be their effects
on the alimentary canal. (1mark)
b) How else is the alimentary canal protected from the effects stated in a) above. (1mark)
10. In an investigation, the pancreatic duct of a mice was blocked by tying it with a string. Explain
how this affected the digestion of food. (2marks)
11. Examination of the alimentary canal of a mammal showed that the food in the small intestine
was more fluid than in the colon. Give an explanation for this observation. (1mark)
12. Name two tissues in plants which are thickened with lignin. (2marks)
a) What is the importance of the following substances in blood clotting process in man?
i) Vitamin K. (1mark)
ii) Thrombin. (1mark)
b) what is the disadvantage of having blood group O. (1mark)
13. Name the part of the seed whose growth brings about epigeal germination. (1mark)
14. a) Differentiate between gaseous exchange and ventilation (1mark)
b) State the respiratory site of the following. (2marks)
i) Fish -
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ii) Insect -
15. In an investigation, a bird was found to use 10 litres of oxygen to give a respiratory quotient of
0.7 during period of flight.
a) Name the type of food that was being respired by the bird. (1mark)
b) Determine the volume of carbon (IV) oxide produced during the same flight. (2 marks)
16. a) Single-celled Organisms with cell walls do not have contractile vacuoles. Suggest why.
(2marks)
b) Rhabdostyla lives in freshwater habitats, such as pond, lakes and rivers where solute
concentration is low. Rhabdostyla has a contractile vacuole that fills with water and empties at
intervals as shown in. The contractile vacuole removes excess water.

Explain, why Rhabdostyla needs to remove excess water. (3marks)

17. Name three plant excretory products deposited in the leaf. (3marks)
18. State one economic importance of each of the following plant excretory products. (2marks)
(a) Tannin
(b) Quinine
19. Study the life cycle shown below and answer the questions that follow.

a) i) Identify the life cycle shown above. (1mk)

ii) Give a reason for your answer in ai) above. (1mk)
b) Explain how the prothoracic gland is important in the life cycle above. (2mks)
c) Name one stage found in the cycle of butterfly but is missing in the above cycle.
20. Name the structures in the human body that detect: (2marks)
(i) External temperature changes.
(ii) Internal temperature changes.
21. (a) Name the hormone whose deficiency may lead to the excretion of glucose in urine.
(b) Name the hormone that controls the reabsorption of sodium ions in the kidney tubules.
22. Oil can be applied on stagnant water to control the spread of Malaria;
a) How does this practice control the spread of Malaria (1mark)
b) Give a reason why this practice should be discouraged (2marks)
23. a) State two importance of predation in an ecosystem. (2marks)
b) Apart from predation state two other biotic factors that will influence the distribution of
organisms in an ecosystem. (2marks)
24. Mention two causes of genetic variation. (2marks)
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25. State two importances of polyploidy. (2marks)
26. a) Pure lines of black and white mice were crossed. All the F1 generation were grey.
Explain the absence of white and black mice in the F1 generation. (1mark)
b) Define multiple alleles (1mark)
27. a). State two theories that explains origin of life (2marks)
b) State three evidences of organic evolution (3marks)
28. a) Explain two limitations of fossil records as evidence of organic evolution. (2marks)
b) Name the evidence of organic evolution exhibited by occurrence of similar amino acid
molecules in a range of organism. (1mark)
29. State the function of the following parts of the eye. (2marks)
Ciliary body –
Sclerotic layer –
30. State three ways through which herbaceous stem obtain support. (3marks)

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 MURANGA SOUTH
231/2
Paper 2
Time: 2 hours
1. Form 2 students set up an experiment on diffusion as shown below. The set up was left to stand for
15 minutes.

a) What does the partially permeable material represent in a cell. (1mark)

b) Give a reason for keeping the water at 37 oC. (2marks)
c) The students carried out a test for proteins using the contents of the partially permeable material
after the 15 minutes. Suggest the conclusions made. (1 mark)
Explain your answer in c) above. (1mark)
d) Amino acids were found to be present in the water. Explain its source and presence there.
2. The diagram below shows the base sequence of part of a nucleic acid strand. Observe it and answer
the question that follows
G T T A C G C A
a) Giving the reason, identify the type of nucleic acid (2 mks)
b) Show the complimentary RNA strand (1mk)
c) Haemophilia is a genetic disorder which is transmitted through recessive gene linked to X-
Chromosome. A woman who is a carrier to haemophilia married a normal man. Using the punnet
square, work out the genotype of F1 Offspring (4 mks)
3. The equation below shows the chemical reaction that takes place in plants.
Carbon (IV) oxide + water → Glucose +A
i) Identify substance A (1mk)
ii) Other than the reactants, state two conditions necessary for this reaction (2mks)
iii) Name the process represented by the equation above (1 mk
iv) Give two types of cell where this process occurs (2mks)
v) How would the process named in (iii ) above be affected by age of leaves in plants (2mks)
4. The apparatus below was set up by a student to find out the changes in gases during
germination

a) After 48 hours the level of water in the U-tube at A and B was as shown. Explain the
observation (3mks)

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b) Calculate the respiratory quotient (RQ) from the equation below:- (2mks)

c) Identify the substrate being respired in the above equation (1mk)

d) i) where in the cell does glycolysis take place? (1mks)
ii) what is oxygen debt? (1mks)
5. The figures below illustrate specialised cells in animal’s body

i) Identify cells M and N (2mks)

ii) State two structural differences between M and N (2mks)
iii) Which of the above specialized cells is found in the gut or human intestines (1mk)
ii) Which organelles are found in large numbers in N (1mks)
iv) Name a carbohydrate and form of energy stored in cell N(2mks)
carbohydrate
form of energy
SECTION B (40 marks)

6. An experiment was carried out to investigate transpiration and absorption of water in a certain
plant species. The plants were potted and supplied with adequate water. The amount of water
lost and absorbed was determined. The results are shown in the table below;
Time of the day Amount of water in grams
Transpiration Absorption
0700 30 15
0900 40 25
1100 48 34
1300 56 45
1500 40 50
1700 25 40
1900 15 28
2100 10 21
a) Using the same axes, plot graphs to show transpiration and absorption of water in grams against time
of the day. (7mks)
b) i) At what time of the day was the amount of water the same for transpiration and absorption;
ii) how much water was absorbed at 1800 hours? (1mk)
c) Explain the shape of the graphs of:-
i) Transpiration (4mks)
ii) Absorption (4mks)
d) Suggest what would happen to transpiration and absorption of water if the experiment was
continued for another 2 hours; (1mks)
e) Name two environmental factors that affect the rate of transpiration (2mks)
7 a) Describe fertilization in flowering plants. (14marks)
b) Explain ways through which plants hinder self-pollination and encourage cross pollination.
8 a). Describe the breathing mechanism in human (12mks)
b). State the structural adaptation of insects tracheal system (8 mks)

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 MURANGA SOUTH
231/3
(Practical)
CONFIDENTIAL
Each candidate should be provided with:-
1. Iodine solution
2. Benedicts solution
3. 1 piece of visking tubing of 10cm
4. Two pieces of thread of 10cm each
5. 30mls of glucose solution labeled L
6. 30mls of starch solution labelled K
7. 4 test tubes
8. Test tube holder
9. Two droppers
10. Means of heating.

MURANGA SOUTH
231/3
Paper 3
(Practical)
Time: 1 ¾ hours
1. The diagrams below are bones obtained from different mammals

a) Identify bone J. (1 mrk)

b) Name the part labelled A. (1 mrk)
c) Give the name of the cartilage that seperates specimen J from another vertebrae (1 mrk
d) State two functions of the cartilage named in c above. (2 mrk)
e) State two structural differences between atlas vertebra and specimen J (2 mrk)
f) i) State the diet of the mammal whose skull is illustrated in drawing K. Explain your answer.
Diet (1 mrk)
Explanation (2 mrk)
ii) Name the parts labeled B and C. (2 mrk)
iii) State the function of the part labeled B. (1 mrk)
2. You are provided with solution labeled L and K.
a) Use the reagents provided to determine their identity. Record your procedure, observation and
conclusion in the table below. (6 marks)
Food substance procedure observation conclusion
starch

Reducing sugars

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b. Tie one end of the visking tubing provided tightly. Put solution K in the visking tubing and tie
the open end. Immerse the visking tubing in the beaker containing solution L. Let the set-up
stand for about 20 minutes.
i) Rinse the visking tubing with distilled water then test the contents in the visking tubing with
iodine and Benedict’s solution. Record your observation and conclusion in the table below.
(2marks)
Test with observation Conclusion
Iodine solution
Benedict’s solution
ii) Test the contents in the beaker with iodine and Benedict’s solution. Record your procedure,
observation and conclusion in the table below. (2marks)
Test with observation Conclusion
Iodine solution
Benedict’s solution

c. Account for your observation in b(i) and (ii) above. (4mks)

3. Study the photograph of some animals in a certain ecosystem and answer the questions that
follow.

a) State the type of biotic relationship exhibited by the animals shown in the photograph.
(1mk)
b. i) Identify which of the two animals, A and B will have the least biomass and give a reason
for your answer (1mk)
ii) Draw a pyramid of biomass for the organisms in the ecosystem (3mks)
c) Explain two survival adaptive features for the organisms illustrated in the photograph
(3mks)
c i) Name the tropic level occupied by the antelope (1mk)
ii) Give a reason for your answer in c (i) above (1mk)
f) Suggest three ways in which the above ecosystem would be affected if there is a prolonged
drought (3mks)

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 MURANGA SOUTH
231/1
Paper 1
MARKING SCHEME
1. Bacteriology;
Virology;
Parasitology;
2. Bait trap;
3. When they are capable of interbreeding; to produce a fertile offspring;
4. The diagram below represents an organism
a) Protoctista;
b) Water;
c) Presence of flagella;
Presence of contractile vacuole;
5. Dorsal nerve cord;
Endoskeleton;
6. 1mm = 1000um
Areas = πr 2 = 22/ 7 x (2000) 2
= (22 / 7 x 2000 x 2000);
= 125714.29µm 2;
b) What is the average size of the cell in micrometers if there were 5 cells on the field of view
125714.29
5
= 25142.858µm 2
7. a) B;
b) Hypertonic;
c) Plasmolysis;
8. a) Digest the membrane of cells that produce them and those of alimentary canal;
b) Covered with mucus lining;
9. Digestion of food was impaired; this is because the blockage of prevented pancreatic juice
containing digestive enzymes from reaching duodenum;
10. Much water is absorbed in the colon; making the food in colon less fluid;

11. Sclerenchyma;
Xylem tissue; ACC Xylem vessel; tracheid;
12. (a) What is the importance of the following substances in blood clotting process in man?
i) Production of prothrombin;
ii) It activates conversion of fibrinogen to fibrin; (which forms a meshwork of fibres on the
cut surface (to trap red blood cells forming a clot)
b) One can receive blood only from blood group O individual;
13. Hypocotyl;
14.
a) Gaseous exchange is passage of respiratory gases across respiratory surface while ventilation is
the process of bringing in air rich in oxygen and removing out air rich in carbon (IV) oxide;
b) State the respiratory site of the following.
i) Fish - gill filaments; reject gills
ii) Insect - tracheoles;
15. a) Lipid / fat or oil; (1mark)

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b)

16. a) Cell walls; inelastic/do not stretch/rigid/inflexible keep shape of cell; cells are turgid/ have
high turgor pressure; resist any increase in volume/ pressure;
These cells do not absorb excess water; the cells will not burst (any two)
b) Water enters into the Rhabdostyla by osmosis; due to higher osmotic pressure in the
Rhabdostyla than the surrounding; to remove the excess water to prevent bursting;
17. Name three plant excretory products deposited in the leaf. (3marks)
Caffein;
Quinine;
Coccain;
Cannabis;
Nicotine; First three
18. State one economic importance of each of the following plant excretory products.
(a) treatment of hides or skin into leather;
manufacture of ink/printing fabrics/dyeing of clothes/printing of patterns in pots. (1st one)
(b) Treatment of Malaria;
19. Study the life cycle shown below and answer the questions that follow.
a) i) Incomplete metamorphosis;
ii) Lack larva; 3 stages; Nymph resembles the adult;
b) Secretes ecdysone/Molting hormone; that promotes molting/Changes in the developmental
stages/change in the developmental forms;
c) Pupa/larva;
20.
(i) Thermo-receptor cells in the skin; rej skin alone.
(ii) Thermo – receptors in the hypothalamus; rej hypothalamus alone.
21. (a) Insulin
(b) Aldosterone;
22. Oil can be applied on stagnant water to control the spread of Malaria;
a) The mosquito larvae are suffocated to death/ pupa are killed / break life cycle of mosquito;
b) It prevents entry of air in water; hence other organisms in the water die out of suffocation;/
causes water pollution
23. a) Control prey- predator population; acc if given population of prey/predator;
Can improve genetic qualities of population by removing the weaker members;
b) Competition;
Parasitism;
Symbiosis;
Saprophytism; acc diseases (any two.)
24. Mutation;
Recombination during crossing over
Fertilization;
Environmental factors; (any 2)
25. Increased yields;
Resistance to drought;
Early maturity;
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 Resistance to pests and diseases;
26. a) The gene for black and white shows incomplete dominance/codominance; and contribute
equally to the phenotype of the offspring.
b) This is where more than two genes control a particular characteristic; by occupying the same
locus but the individual possess only a pair.
27. a). Special creation;
Chemical evolution;
b) Fossils records;
Comparative anatomy;
Comparative embryology;
Comparative serology;
Geographical distribution of organisms;
Cell biology any three correct;
28. a) Only partial preservation of the organisms occurs because softer parts decay hence
incomplete records;
Distortion during sedimentation;
Destruction due to geological activities; eg erosion, earthquakes, faulting and
uplifting; (mark any 2)
b) Cell biology;
29. State the function of the following parts of the eye. (2marks)
Ciliary body –
It has ciliary muscles - which contract and relax to change the shape of lens during
accommodation.
Sclerotic layer –
It protects the eye and gives its shape.
30. State three ways through which herbaceous stem obtain support. (3marks)
- Turgidity of cell;
- Twinning around other plants;
- Use of tendrils; e.g pumpkins.;

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 MURANGA SOUTH
231/2
Paper 2
MARKING SCHEME
1.
a) Cell membrane;
b) To provide optimum/ favourable/ suitable temperature; for enzyme/protease action;
c) Proteins absent;
Explain your answer in c) above.
Proteins were broken down / hydrolysed/ digested to amino acids by the action protease;
d) Proteins broken down into amino acids; diffused to the water through the partially permeable
material; because they are small in size;
2. The diagram below shows the base sequence of part of a nucleic acid strand. Observe it and answer
the question that follows
a) DNA; presence of Thymine
b) C A A U G C G U
c)

3.
i) Oxygen;
ii) Sunlight, energy , chlorophyll, optimum temperature first two
iii) Photosynthesis;
iv) Palisade cell, guard cell, mesophyll cell
v) As the leaf ages the amount of chlorophyll, reduces ; leading to the rate of photosynthesis decreasing
(reducing );

4. a) Germinating seed respired aerobically;oxygen was used up and carbon(IV)oxide produced was
absorbed by sodium hydroxide solution; partial pressure was created hence atmospheric pressure
pushed water down at A and level raised at B;
b)

c) Lipids/fats
d) i) cytoplasm
ii) extra amount of oxygen required to get rid of lactic acid that accumulate in the tissue when
oxygen demand is less than supply.
5.
i) M smooth muscle;.
N Striated muscle/skeletal muscle;

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 ii) State two structural differences between M and N (2mks)
M N
Lacks striations Has striation;
Uninucleated Multinucleated;
iii) M/smooth muscle;
iii) mitochondria;
iv) carbohydrate-glycogen
form of energy-adenosine triphosphate
6.
a) Using the same axes, plot graphs to show transpiration and absorption of water in grams against time
of the day. (7mks)

b) i) 1400 hrs;
ii) 34g;
c) Explain the shape of the graphs of:-
i) Transpiration (4mks)
0700 -1300hrs increase in the rate of transpiration; due to increase in light intensity and
Increase in temperature;
1300 – 2100 hrs decrease in the rate of transpiration; due to decreasing light intensity and
Decrease in temperature.;
ii) Absorption (4mks)
0700 – 1500hrs Increase in the rate of absorption of water; to replace water lost
through transpiration;
1500 – 2300hrs decrease in the rate of absorption of water; due to decrease in the rate of
Transpiration;
d) Suggest what would happen to transpiration and absorption of water if the experiment was
continued for another 2 hours; (1mks)
Both transpiration and absorption decreases;(due to darkness and low night temperatures)
e) Name two environmental factors that affect the rate of transpiration (2mks)
Wind
Humidity
Atmospheric pressure
Light
Temperature any two correct
7. a) Describe fertilization in flowering plants. (14marks)
The pollen grain contains the generative nucleus and a tube nucleus;
When the pollen grain lands on the stigma; it absorbs nutrient and germinates forming a pollen tube;
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 This pollen tube grows through the style pushing its way between the cells; as it gets nourishment
from these cells;
The tube nucleus occupies the position at the tip of the growing pollen tube; while the generative
nucleus follows behind the tube nucleus;the generative nucleus divides by mitosis; to form two male
gamete nuclei;
The pollen tube enters the ovule through the micropyle;
When the pollen tube penetrates the ovule, the tube nucleus disintegrates and the pollen tube bursts
open leaving a clear way for the male nuclei;
One male nucleus fuse with the egg cell nucleus; to form a diploid zygote; which develops into an
embryo;
The other male gamete nucleus fuses with the polar nucleus; to form a triploid nuclei; which forms
the primary endosperm;
b). Explain ways through which plants hinder self-pollination and encourage cross pollination.
a) Heterostyly;
Where the stigma is located in a position higher than the anthers; hence cannot receive pollen grains;
reject stigma taller than anther
b) Protogyny and protandry;
Protandry - Stamens ripen early and release their pollen grains before the stigma, mature to receive
them; e.g. in sunflower.
Protogyny - The stigma matures earlier and dries before the anthers release the pollen grains;
c) Monoecism and Dioecism;
Dioecism - Where the staminate and pistillate flower are located in different plants;
Monoecism - Where the staminate and pistillate flower are located in the same plant but separate;
d) Self-sterility and incompatibility;
Pollen grains are sterile to the stigma of the same flower, e.g. in maize flower.
8. a). Describe the breathing mechanism in human (12mks)
Inhalation
External intercostal muscles contracts;
Internal intercostal muscles relax;
Ribcage moves upward and outwards/ raised;
Diaphragm muscles contracts and it flatten;
Volume of thoracic cavity increases;
(Air) pressure decreases; air is drawn into the lungs from the atmosphere through the nose;
Exhalation
Internal intercostal muscles contracts;
External intercostal muscles relax;
Ribcage moves downwards and inwards;
Diaphragm muscles relax and acquire the dome shape;
Volume of the thoracic cavity decreases;
(Air) pressure inside thoracic cavity increases; air is forced out of the lungs;
(b). State the structural adaptation of insects tracheal system (8 mks)
Spiracles are openings through which gases ( oxygen and carbon (IV) oxide) enters or exit the
tracheal system;
Valves on the spiracle controls the opening and closing of the spiracles;
Hair on the spiracles trap foreign particles and prevent their entry in the tracheal system;
Hair on the spiracles trap moisture reducing water loss;
Trachea is strengthened with rings of chitin to prevent them from collapsing/ keeping trachea open;
Tracheoles are thin walled for faster diffusion;
Tracheoles contain a fluid/ moist lining which absorb oxygen thus facilitating diffusion into the
tissues; Tracheoles are higly branched to increase the surface area for gaseous exchange;

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 MURANGA SOUTH
231/3
Paper 3
MARKING SCHEME
1. The diagrams below are bones obtained from different mammals
a) vertebrae
b) Anterior zygapophysis/pre-zygapophysis (reject pre-zygapophyses and metapophyses)
c) inter-vertebral disc
d) State two functions of the cartilage named in c above. (2 mrk )
i) It acts as a cushion that absorbs shock
ii) It reduces friction
iii) It makes the vertebral column flexible by allowing for certain degree of movement between the
vertebrae
e) State two structural differences between atlas vertebra and specimen J(2 mrk )
Atlas Specimen J
i) Has no centrum i) Has a centrum
ii) Has a wide winglike transverse ii) Has a branched transverse processes
process which is not branched

f) i) Diet vegetation/grass acc plant

Explanation Presence of diastema
Absence of canines
Absence of incisors in front of upper jaw/presence of horny pad
ii) Name the parts labeled B and C. (2 mrk )
B-horny pad
C-diastema
iii) Provides hard surface against which grass is pressed and cut by lower incisor
2. You are provided with solution labeled L and K.
a)
Food substance procedure observation conclusion
starch Put solution K in a test Blue black Presence of starch
tube add iodine
solution
Put solution L in a test No colour change/colour Absence of starch
tube add iodine of iodine/brown
solution
Reducing Put solution K in a test No colour change; colour Absence of reducing
sugars tube and equal volume of benedicts solution sugars
of Benedict’s solution; remains
heat to boil
Put solution L in a test Colour changes to green, Presence of reducing
tube Add Benedict’s yellow, orange, brown sugars.
solution; heat to boil.
b. Tie one end of the visking tubing provided tightly. Put solution K in the visking tubing and tie
the open end. Immerse the visking tubing in the beaker containing solution L. Let the set up
stand for about 30 minutes.
i) Rinse the visking tubing with distilled water then test the contents in the visking tubing with
iodine and Benedict’s solution. Record your observation and conclusion in the table below.
(2marks)

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 Test with observation conclusion
Iodine solution Blue black Presence of starch
Benedict’s solution Colour changes to orange; Presence of reducing sugars.
ii) Test the contents in the beaker with iodine and Benedict’s solution. Record your procedure,
observation and conclusion in the table below. (2marks)
Test with observation conclusion
Iodine solution No colour change/colour of Absence of starch.
iodine/brown.
Benedict’s solution Colour changes to orange; Presence of reducing sugars
c. Reducing sugar molecules are small in sizes; able to pass through the semi – permeable
membrane into the visking tubing by diffusion. (2mks)
Starch molecules are too large; to pass through the semi -permeable membrane/visking tubing
into the beaker. (2mks)
d. What does a visking tubing equate to in a living organism? (1mark)
Cell membrane (1mk)
3. Study the photograph of some animals in a certain ecosystem and answer the questions that
follow.
a) Predation / Predator-prey
b. i) B-is at higher tropic level than A /
B is a secondary consumer while A is a primary consumer;
Biomass decreases from primary to secondary as a result of loss of energy from one tropic
level to another.
ii) Draw a pyramid of biomass for the organisms in the ecosystem (3mmks)

Cheetah Secondary Consumer

Antelope Primary Consumer

Grass
Producer

c) Both animals camouflage / blend well with the environment hiding themselves
Both animals are very swift in running
Animal B has strong jaws with carnassial teeth
d i) Primary consumer
ii) It feeds on grass ;
f) Most grass will die / dry;
Some organisms (antelope and cheetah ) will starve to death;
Some organisms may migrate in search for food and shelter

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 KASSU JET EXAMINATIONS
231/1
PAPER 1
TIME: 2 HOURS
1. (i) Some herbaceous stems have very little strengthening tissue yet still remain upright.
Explain. (2 marks)
(ii) Name the strengthening material in sclerenchyma (1 mark)
2. State the functions of the following structures of the human brain. (3 marks)
(i) Cerebrum
(ii) Cerebellum
(iii) Medulla oblongata
3. The diagram shows a simple reflex arc.

Explain how an impulse is transmitted across the gap between neurons C and D (3 marks)
4. (a) Based on the structure available on this diagram classify this type of stem. (1 mark)

(b) How is the other type of stem different from this one? (1 mark)
5. State the importance of tactic responses among some members of kingdom Protoctista.
6. State two differences between tropisms and taxes. (2 marks)
7. Explain continental drift as an evidence of evolution. (2 marks)
8. Why are some bacteria able to resist the effect of antibiotics? (2 marks)
9. The diagram below illustrates the arrangement of bones and muscles in the human arm.

(i) Name the bone labelled K (1 mark)

(ii) Explain how the upward movement of the lower arms is brought about by the bones and
muscles shown in the diagram above. (2 marks)
10. Jerry’s blood crystallizes at low oxygen concentration. He is married to Janice whose blood does
not crystalize in low oxygen concentration. Work out the probability of the couple producing
children with the same fate as their father Jerry. Use the letter d to denote for crystallization at
low oxygen. (4 marks)
11. State the causative agents for the following diseases
(i) Syphilis.. (1mark)
(ii) Trichomoniasis (1mark)
12. What do you understand by the term ecological niche? (1mark)

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13. The diagram below shows the feeding relationship between rabbits and wolves in a given habitat
over a period of 25 years. Study it and answer the questions that follow

(i) Name the type of feeding relationship. (1mark)

(ii) Which organism in the relationship above is represented by the curve labeled X and Y
14. The diagram below represents a human reproductive organ.

(i) State two adaptations of the structure labelled L to its functions. (2 marks)
(ii) Explain the role of the role of the gland labelled K (1mark)
15. The diagram below shows different developmental stages of a given organism.

(a) Identify the stages represented by letter Y and Z (2 marks)

(b) Identify the hormones which play a role in the above process and state where they are produced
15. State the mode of asexual reproduction in yeast (1 mark)
16. Name two substances that leave the foetal blood through the placenta into maternal blood
stream. (2 marks)
17. Besides venation, State two other external characteristics of leaves that can be used to classify
plants. (2 marks)
18. The graph below shows the concentration antibodies produced during a primary infection and
secondary infection against time. Study the graph and answer the question below.

(a) Name the type of immunity illustrated by the graph (1 mark)

(b) In a blood test a few drops of anti-B serum were added to two samples of blood separately. No
agglutination occurred in either of them. What were the blood groups of the two samples
(2 marks)
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19. (a) State two ways in which opening of the stomata is important to plants (2 marks)
(b) Explain how accumulation of carbon (IV) oxide in a leaf affects the stomata (3 marks)
20. Explain each of the following observations:
(a) The stump of a severed tree trunk may exude copious quantities of fluids after cutting
(b) Leaf fall reduces the rate of transpiration (1 mark)
(c) The xylem tissue is made up of dead tissue (1 mark)
21. (a) During the process of respiration, the breakdown of glucose occurs in phases.
Explain why these phases are necessary? (2 marks)
(b) Explain why the rate of production of lactic acid increases during exercise (2 marks)
22. Explain why body temperature regulation is more difficult in a hot humid conditions
(2 marks)
23. Suggest two ways in which plants compensate for lack of complex excretory organs
24. State two factors that would lead to a decrease in the rate of photosynthesis. (2 marks)
25. Knowledge and skills acquired in the course of studying biology are very important. Justify the
above statement. (2 marks)
26. The ileum is highly coiled in mammals, State two biological significance of this feature?
27. Caecum is part of the digestive system of some herbivores. What is its role in digestion?
28. The diagram below is that of a certain plant tissue.

a) Name the structures labeled G. (1 mark)

b) State two adaptations of the specialized cell labeled A to its functions? (2 marks)
29. A student was viewing a slide prepared of an epidermal cell under medium power objective
lens. The specimen appeared blurred. Which part of the microscope would the student adjust to
obtain a clearer view? (1mark)
30. (i) Define active transport. (1 mark)
(ii) Why are the following factors important in the process of active transport in cells:
a) Oxygen (1 mark)
b) Optimum temperature (1 mark)
31. (i) Suggest a likely habitat of an organism with an active contractile vacuole. (1 mark)

(ii) Give a reason for your answer above. (1 mark)

32. How is dark stage of photosynthesis dependent on light stage? (2 marks)

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 KASSU JET EXAMINATIONS
231/2
Paper 2
Section A
Answer all questions in this section
1. Haemophilia is a genetic disorder caused by a recessive sex-linked gene. A phenotypically normal
couple got a hemophiliac son.
a) State the genotypes of the parents (2marks)
b) Using a genetic cross, determine the genotypes of the couple’s children (4marks)
c) Explain why hemophilia is common in males than in females (2marks)
2. A plant physiologist studying the transport mechanisms in a particular plant species under different
environmental conditions. He measured the rates of water uptake, nutrient absorption and sugar
translocation in the xylem and phloem over 48 hours period. The data is summarized in the table
below.
condition Water uptake in Nutrient absorption Sugar translocation
mm/hr. Mg/hr. Mg/hr.
Normal 15 8 12
High soil salinity 10 5 7
Drought condition 6 4 5
(a). Compare the rate of water uptake during normal conditions and during high salinity conditions
(b). Compare the rate of sugar translocation during normal conditions and during drought conditions
(c). Suggest two physiological conditions that plants use to cope the drought conditions
(d) Name the physiological process involved in:
I. Water uptake (1mark)
II. Sugar translocation (1mark)
3. The diagram below shows a food web, study it and answer the questions that follow.

Lizard
Mongoose

Grass hopper Chicken Human being

Grass Vulture
Termite Weaver bird Hawk

Sheep Hyena
(a) Name the tropic level occupied by the following organisms. (2marks)
(i) Human being
(ii)Grass
(b) i) Identify the organism with the least biomass in this ecosystem. (1mark)
ii) Explain your answer in b(i) above. (2marks)
(c) Name two ways a scientist would use to identify the type of food eaten by the various organisms in
order to design the food web (2marks)
(d) Extract a food chain with a quaternary consumer (1mark)

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4. An experiment was carried out to examine the rate of respiration (breaths per minute). The data was
collected from infants, children and adults and the data summarized in the table below
Age group in years Rate of respiration (breaths /min)
Infants (0-1) 30-60
Children (5-10) 20-30
Adults20-30 12-20
a). Account for the trend in respiration rates from infancy to adulthood (2marks)
b). Apart from age name two other factors that affect the rate of respiration (2marks)
c) Explain how anaerobic respiration can be applied in making dairy products (2marks)
d). Name the part of the brain that controls the rate of breathing (1mark)
(e) Under what condition are proteins utilized as respiratory substrate (1mark)
5. In an experiment to investigate a factor affecting photosynthesis, a leaf of a potted plant which had
been kept in the dark overnight was covered with aluminum foil as shown in the diagram below. The
set up was kept in sunlight for three hours after which a food test was carried out on the leaf

(a) Explain the purpose of this experiment? (1mark)

b) What food test was carried out? (1mark)
c) i) State the results of the food test (2marks)
ii) Other than the factor being investigated above, State two other factors that increase the rate
of the process studied (2marks)
SECTION B
The following results were obtained from a study of germination and early growth of cowpeas
(Vigna unguiculata). The grains were sown in soil in a greenhouse and at two days intervals.
Samples were taken, oven-dried and weighed. Graph is shown below.
Time after sowing (days) 0 2 4 6 8 10 12
Dry mass of embryo (g) 0.02 0.02 0.08 0.16 0.24 0.34 0.35
a) Using a suitable scale, plot a graph of dry mass of embryo against time (6 marks)
b) Give the name of the type of curve you have obtained in 6 (a) above? (1mark)
c) Explain why the rate of increase is low between day one and day three? (2 marks)
d) State three reasons for the limited rate of increase between day nine and day eleven.
e) Name a phylum whose growth does not take the shape of the curve drawn above.
f) What name is given to the curve exhibited by organisms in the phylum you have named in (e) (i)
above? (1mark)
g) What causes the behavior of the curve mentioned in (e) (ii) above? (1mark)
h) State one advantage of using dry mass instead of fresh weight in estimating growth of an organism.
i) State the role of the following growth hormones in plant growth and development
i. Abscisic Acid (ABA) (2marks)
ii. Florigens (1 marks)
7 a). Describe the mechanism of inhalation in bony fish (10 marks)
b). Describe the response of a young herbaceous plant to each of the following unidirectional external
stimuli and for each give one significance. (10 marks)
i) Light
ii) Contact
8. a) Explain the role of the liver and pancreas in blood sugar regulation (10 marks)
b) Describe the adaptations of halophytes to their habitats (10 marks)

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 KASSU JET
PAPER 3
CONFIDENTIAL
1. Specimen W( 5 soaked bean seeds)
2. 6 ml Liquid G (Hydrogen peroxide)
3. 1% copper sulphate,
4. 2M sodium hydroxide,
5. Distilled water
6. 5 ml ethanol
7. Iodine solution
8. Pestle and mortar
9. 100ml beaker
10. 10ml measuring cylinder
11. 2 labels
12. 2 boiling tubes
13. 6 test tubes
14. Test tube holder
15. Source of heat
16. Specimen Q (Bougainvillea flower -complete)
17. A hand lens
18. Scalpel

KASSU JOINT EXAMINATIONS

231/3
Paper 3 (PRACTICAL)
TIME: 13/4 hour
1. You are provided with specimen W, liquid G (Hydrogen peroxide) and 1% copper sulphate
solution, 2M sodium hydroxide solution, distilled water, ethanol and iodine solution. Use them
to carry out tests below.
Place five pieces of specimen W into a mortar and crush into paste using a pestle. Transfer the
paste into 100ml beaker and add 30ml of water and stir then divide the solution into two equal
portions in two different boiling tube. Label the portions X and Y.
a) Divide portion X into two separate test tubes.
i) To the first test tube add 2ml of hydrogen peroxide and record your observations. (1mark)
ii) Boil the contents of the second test tube then add 2ml of hydrogen peroxide and record your
observations. (1mark)
b) Explain your observation in (ii) above. (2marks)
c) Use portion Y to test for the food substances present using the reagents provided.
d) Name the enzyme in the human digestive system required for the complete digestion of the food
substance absent. (1mark)

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2. You are provided with specimen Q. Observe it then compare with the photograph R shown
below and answer the questions that follow.

Photograph R

(a) Name the classes of organisms represented by Q, R and P and give a reason for each one basing
on observable features only (6marks)
(b) Specimen P probes into nectaries of specimens Q and R. State two characteristics of living
organisms achieved after the process (2marks)
(c) Explain the adaptations of specimen in photograph R to pollination (2marks)
(d) Carefully remove one stamen of specimen Q then draw a well labeled diagram. (3marks)
3. You are provided with photographs of specimens P and Q examine them carefully and answer
the questions that follow.

a) Name the region of the mammalian skeleton from which the specimen P and Q were obtained
from. (2 marks)
b) With a reason identify the specimen represented in the photographs above (4marks)
c) State two ways specimen Q is suited to its function (2marks)
d) State two structural differences between specimen P and Q (2marks)
e) The actual length of the hand-lens next to specimen Q is 6. 5cm.Use this information to
calculate the actual lateral length of specimen P (3marks)

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 KASSU JET EXAMINATIONS
231/1
PAPER 1
MARKING SCHEME
1.
i) They have Parenchyma cells / tissues which absorbs water and become turgid
ii) Lignin
2. State the functions of the following structures of the human brain. (3 marks)
Cerebrum. Controls senses such as hearing and taste; integrating of sensory impulse human
individualistic vision intelligence memory.
Cerebellum. Co-ordinate body movement/ maintain balance and posture / dextenty in the movement
Medulla oblongata; Controls breathing / vomiting / swallowing involuntary movement /
salivation / body temperature / sleep and wakefulness / feeding and drinking
3. When an impulse reaches the synaptic knob [ of the sensory neurone] , it causes the synaptic knob to
discharge the neurotransmitter into the synaptic cleft;
The neurotransmitter diffuses across the cleft and binds to the specific receptors on the postsynaptic
membrane;
16. (a) Herbaceous stem
(b) They have support tissues whose cells have stiff, thickened or lignified walls;
17. Move towards favorable environment;
6. State two differences between tropisms and taxes. (2 marks)

Tropism Taxes
i) Growth responses and are therefore more Locomotory response therefore temporary
permanent;
ii) Responses are slow; Responses are fast
iii) Tropisms are brought about by growth Taxes are not influenced by growth
hormones; hormones

7. Current continents existed as one large land mass; the present continent drifted leading to isolation of
organisms; organisms in each continent evolved along different lines, hence emergence of new
species
8. They have a gene for resistance which is acquired through mutation; When bacteria are exposed to
antibiotics for some time, they become used or adapted to living in presence of the drug The gene is
passed to the offspring therefore establishing a population of drug resistant;
9. The diagram below illustrates the arrangement of bones and muscles in the human arm.
(i) Name the bone labelled K (1 mk)
K – ulna;
(ii) The biceps muscles contract while triceps relaxes; this causes the lower part of the arm to move
upwards;
18.
Parental genotype: dd x DD;

Gamates ;
GAMATES D D
d Dd Dd
d Dd Dd
Probability 0%;
19. State the causative agents for the following diseases
(i) Syphilis Treponema pallidium (1mark)
(ii) Trichomoniasis Trichomonas vaginalis (1mark)
20. The position that an organism occupies in a habitat including its physical space and role
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21.
(i) Predation
(ii) X rabbits
Y wolves
22. The diagram below represents a human reproductive organ.
(i) Seminiferous tubules are long and highly coiled tubes; provides a large surface area for sperm
production;
Giant sertoli cells; which nourishes the sperms;
Interstitial cells secrete male hormones /androgens;
(ii) Secretes an alkaline fluid that neutralizes vaginal fluids;activates the sperms;.
23.
(a) Y nymph
Z Adult
(b)
Hormone Site of production
Ecdysone Prothoracic gland
Juvenile Corpora allata

15. Budding
16. Carbon (IV) oxide
Nitrogenous waste
17. Phyllotaxy;leaf apex;leaf type;leaf margin;leaf shape
18.
(a) Naturally acquired active immunity
(b) B
AB
19. (a) Transpiration
Gaseous exchange
(b) Accumulation of carbon (iv) oxide in the leaf lowers the pH of the cell sap of the guard cell;
this activates enzymes that catalyze the conversion if starch to glucose. Making the cell sap of the
guard cell hypertonic to cell sap of the adjacent epidermal cells; guard cells absorb water become
turgid leading to opening of the stomata.
20. Explain each of the following observations:
(a) Root pressure
(b) Reduces the total surface area expected for water loss
(c) To prevent utilization of the substances they transport
21. (a) High amounts of energy produced would burn the cells
- Some of the intermediate products a given step serves as raw materials for other reactions
(b) Demand for oxygen is higher than the supply: cell start respiring anaerobically to produce energy
22. High temperature leads to increased sweating: high humidity slows down evaporation leaving
accumulation of sweat on skin;
23. They manufacture their own food hence less water
Most of their wastes are less toxic
24. - Very low temperature
- Low concentration of Carbon(IV) oxide
- Low light intensity
33. Study of biology enables understanding of the developmental stages in the human body, solving
environmental like drought, global warming and enhanced international cooperation in areas of
medical research.
34. Slow down the rate of movement of food thus allow more time for absorption and digestion to take
place

Page | 160
35. Contain anaerobic bacteria which secrete enzyme /cellulose that digest cellulose;
36. The diagram below is that of a certain plant tissue.
a) Palisade mesophyll
b) Chloroplasts present to synthesize glucose raising osmotic pressure of guard cells; uneven thickness
of the wall; allow opening of stoma
37. Fine adjustment knob; mirror; diaphragm
38. (i) Movement of molecules or ions against a concentration gradient across a living cell
membrane with the utilization of energy;
ii) Why are the following factors important in the process of active transport in cells?
c) Oxidizes glucose to generate energy used in active transport;
d) Activates respiratory enzymes increasing rates of oxidation of glucose hence high rate of active
transport;
39. i) Fresh water
ii) Osmoregulation
40. Light stages generate hydrogen atoms and ATP; utilized in dark reaction of photosynthesis;

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 KASSU JET
231/2
BIOLOGY -theory
Paper 2
Section A
Answer all questions in this section
1. Haemophilia is a genetic disorder caused by a recessive sex-linked gene. A phenotypically
normal couple got a hemophiliac son.
a) State the genotypes of the parents (2mks)
Father: XHY
Mother: XHXh
b) Using a genetic cross, determine the genotypes od the couple’s children (4mks)
c) Explain why hemophilia is common in males than in females (2mks)
Since males have one X and one Y chromosome, and the genes present on X don't have counter
genes on Y; only one affected gene (to be present on X) is required for the disease to occur in
males;
2.
a). Compare the rate of water uptake during normal conditions and during high salinity conditions
In normal conditions the rate of water uptake is higher than in high; because in high salinity
soils the soil solution is hypertonic to the cell sap of root hair cells resulting to slow water
absorption;
b). Sugar translocation during normal conditions is higher than during drought conditions: because
less water is available for photosynthesis
c). -leaf fall
-midday closure of stomata
-Reversed stomatal rhythm
(d) I. osmosis
II. diffusion/cytoplasmic streaming/mass flow
3. The diagram below shows a food web, study it and answer the questions that follow.
(a) Name the tropic level occupied by the following organisms. (2mks)
(i) Quaternary consumer
(ii) Tertiary consumer
(b) (i) vulture
(ii) At each trophic level, energy is lost during respiration and decomposition; hence there is
less energy is available to organisms up the trophic level,
(c) Fistulation
Observation
Dentition
Structure of the alimentary canal
Analysis of feaces
(d) Extract a food chain with a quaternary consumer (1mk)
Grass → rasshopper → lizard → mongoose → vulture
4.a). From infancy to adulthood the rate of respiration increases; This is because infants have a
higher rate of cell division which requires energy, as they grow towards adulthood the rate of
cell division decrease;
b). Emotions
Exercise
c) Bacteria in milk breaks down lactose into lactic acid and energy: The lactic acid makes the
milk sour
d). Medulla oblongata
Page | 162
e) During extreme starvation
5.
(a) To investigate the necessity of sunlight for photosynthesis
b) Test for starch
c) i) The part covered with aluminium foil retains the brown/yellow colour of iodine
The uncovered part stained blue-black
ii) Aluminium prevented penetration of sunlight, photosynthesis did not take place and no
starch form;Uncovered part was exposed to sunlight, photosynthesis occurred and starch
was formed
ii)
i) -Increased carbon (IV) oxide concentration
ii) Optimum temperature
iii) Increased water supply
SECTION B
Answer Question 6(compulsory) and either question 7 or 8 in the spaces provide after
question 8
6. Using a suitable scale, plot a graph of dry mass of embryo against time (6 marks)
a) Using a suitable scale, plot a graph of dry mass of embryo against time (6 marks)
b) Give the name of the type of curve you have obtained in 6 (a) above? (1 mark)
S-shaped curve/Sigmoid curve
c) Explain why the rate of increase low between day one and day three? (2 marks)
0-2 – due to Inhibition (absorption of water)
2-3 – due to germination starts where only few cells have undergone division.
d) State three reasons for the limited rate of increase between day nine and day eleven.
1. Most cells fully differentiated.
2. Few cells still diving.
3. Environmental factors start limiting.
e) Name a phylum whose growth does not take the shape of the curve drawn above.
Arthropoda . (Rej. Spelling error)
f) What name is given to the curve exhibited by organisms in the phylum you have named in (e)
(i) above? (1 mark)
Intermittent.
g) State one advantage of using dry mass instead of fresh weight in estimating growth of an
organism. (2 marks)
- Dry mass is not affected by environmental conditions while fresh weight is dependent on the
amount of water in the plant which fluctuate with environmental factors affecting transpiration
rate.
h) What causes the behavior of the curve mentioned in (e) (ii) above? (1 mark)
Ecdysis(moulting) followed by development of exoskeleton
i) State the role of the following growth hormones in plant growth and development
i. Abscisic Acid (ABA) (2marks)
- Causes seed dormancy/bud dormancy;
- Causes abscission of leaves/fruit fall;
ii. Florigens (1 marks)
- Promote flowering
7 (a). Describe the mechanism of inhalation in bony fish (10mks)
(b). Discuss the role of auxins in plant coordination under the following stimuli
(i) Gravity (5marks)
(ii) Light (5marks)
8. (a) Explain the role of the pancreas and the liver in blood sugar regulation (10mks)
Page | 163
 (b) Describe the adaptations of halophytes to their habitats (10mks)
7 (a)
• The floor of the mouth cavity is lowered/the mouth is opened;
• This increased the volume of the mouth cavity and reduces the pressure;
• Water rushes/flows into the mouth cavity;
• The fish closes the mouth/floor of the mouth is raised;
• This decreases the volume but decreases the pressure;
• The operculum bulges outwards increasing the volume of the opercular cavity and decreasing
the pressure;
• Water from the mouth enters the gill chamber/opercular cavity and flows the gills in a
countercurrent direction to blood flow;
• Oxygen which is in higher concentration in water diffuses into the blood capillaries;
(b) Light from one direction causes lateral migration of auxins to the darker side; where the
accumulate causing faster growth than the lit side; which results in curvature of the shoot
towards light; this helps the plant to grow towards light to obtain (light) energy for
photosynthesis;
Contact/ touch causes lateral migration of auxins to the opposite side; where they accumulate
and cause faster growth; which result in curvature; around the object; the curvature helps the
plant to obtain mechanical support;
8(a) Role of the pancreas and liver in blood sugar regulation
- When blood sugar raises above normal, the interstitial cells of the islets of Langerhans; in the
pancreas; is stimulated to secrete insulin;
- Insulin is transported in blood to the liver where they stimulate the liver cell;to:
 Convert excess glucose to glycogen for storage in the liver;
 Convert excess glucose to fats for storage as adipose tissue in the skin;
 Inhibit the conversion of glycogen to glucose;
 Increasing the breakdown of glucose;
Lowering the blood sugar level to glucose;
- When the blood sugar level drops below normal, the alpha cells of the Islets of Langerhans of
the pancreas; are stimulated to secrete glucagon; The glucagon is transported in blood to the
liver cells; where it stimulates them to:
 Stimulate the Conversion glycogen and fats to glucose;
 Reduce the breakdown of glucose
This raises the blood sugar level to normal
b) Adaptation of halophytes to their habitats
Halophytes have roots which concentrate a lot of salts; in them enabling them to greate a
concentration gradient so as to absorb water by osmosis in the normal way;
Some plants have salt secreting cells; that secrete excess salts that enable them to increase the
concertation of their cells to enable normal absorption of water by osmosis;
Some halophytes such as mangroves have pneumatophores; which emerge above water to
obtain atmospheric oxygen for respiration;
Mangroves growing on mud flats have buttress roots; for support/anchorage;
Most of the submerged halophytes are found close to the surface; to ensure reception of
sufficient sunlight for photosynthesis;
Halophytes in deeper waters have sensitive chloroplast; that enable them to carry out
photosynthesis using light of low intensity;
They have fruits that have large aerenchymatous tissues; for air storage to enable them to
float/be buoyant;

Page | 164
 KASSU JOINT EXAMINATIONS
231/3
Paper 3
(PRACTICAL)
MARKING SCHEME
1.
b) Divide portion X into two separate test tubes.
i) Effervescence/Fizzing/Bubbles of a colourless gas/Foam
ii) No Effervescence/Fizzing/Bubbles of a colourless gas/Foam
a) Explain your observation in (ii) above. (2marks)
Boiling denatured enzyme catalase hence hydrogen peroxide was not broken-down produce oxygen
and water
b) Use portion Y to test for the food substances present using the reagents provided.. (9marks)
Food substance Procedure Observation Conclusion

Starch To a portion of the test solution, Solution turns blue- Starch present
add iodine solution dropwise and black
shake
proteins To a portion of the test solution Solution turns Proteins present
add equal amount of sodium purple
hydroxide followed by copper(ii)
sulphate solution dropwise

Lipids To a portion of the test solution in No white Lipids absent

a test tube add equal amount of emulsion/suspension
ethanol followed by water and is formed
shake

1. Name the enzyme in the human digestive system required for the complete digestion of the food
substance absent. (1mark)
2. You are provided with specimen Q. Observe it then compare with the photograph R
shown below and answer the questions that follow.
(a) Name the classes of organisms represented by Q, R and P and give a reason for each one basing on
observable features only
b) Specimen P probes into nectaries of specimens Q and R. State two characteristics of living organisms
achieved after the process (2mks)
Nutrition Reproduction Locomotion
(c) Explain the adaptations of specimen in photograph R to pollination (2mks)
Brightly coloured/conspicuous; for insects to locate them at a distance; Scented; to attract insects;
(d) remove one stamen of specimen Q then draw a well labeled diagram (3mks)
3. You are provided with photographs of specimens P and examine them carefully and answer the
questions that follow.
a) Name the part of the mammalian skeleton from which the specimen P and Q were obtained from.
(2 marks)
P thoracic region
Q Neck region
b) With a reason identify the specimen represented of the photographs above
Specimen P
Identity (1mark)

Page | 165
 Thoracic vertebra
Reason
Long neural spine
Transverse process modified into tubercular facet Centrum modified into capitular facet
Specimen Q
Identity (1mark)
Cervical vertebra (1mark)
Reason
Branched transverse process
State two ways specimen Q is suited to its function (2marks)
Vertebratenal canals; for passage of blood vessels and nerves
Branched transverse process; to increase surface area for attachment of neck muscles;
c) State two structural differences between specimen P and Q (2marks)

Specimen P Specimen Q
− Vertebrateria / canals absent − Vertebraterial canal present
− transverse processes modified to − Short and branched transverse processes
capitular facet
− Long neural spine − Short neural spine

d) The actual length of the hand-lens next to specimen Q is 6. 5cm.Use this information to calculate the
actual lateral length of specimen P (3marks)

Page | 166
 ITHANGA/KAKUZI JOINT
PAPER ONE
231/1
TIME: 2HRS
1. Define
a. Niche (1mk)
a. Eutrophication (1mk)
2. Name the part of the eye where image is formed (1mk)
3. State two structural similarities between mitochondrion and chloroplast (2mks)
4. A layer of glycerine was applied on upper surface of a fresh water floating plant that had been kept in
the dark for 24 hours. The plant was left undisturbed in brighter light. After 3 hours test a starch was
carried out in the leaves.
a. State the observation that was made (1mk)
b. Account for the observation (2mks)
5. Study the diagram below and answer the question that follows

a. Identify the type of plant-based on habitat (1mk)

b. Give two reasons for your answer in above (2mks)
c. Explain stomata modification you would expect to be found in the plant (2mks)
6. During oxidation of certain food substance the respiratory quotient was found to be 0.718
a. Name that type of food substance being oxidized (1mk)
b. State two advantages of using food substances named (2mks)
c. Give reason why it is difficult to calculate respiratory quotient RQ in plants (1mk)
d. Give one reason why knowledge of respiratory quotient is important (1mk)
7. The quantity of urine passed per day was measured in four mammals A, B, C and D of the same species
in the natural habitats. There result were shown belong

VOLUME OF
URINE

A B C D

a. Name the form of nitrogenous waste likely to be in organisms D? Explain (2mks)

b. Organism C explain (2mks)

Page | 167
8. Explain why advisable to breathe through the nose rather than the mouth in human (2mks)
9. Name organelle that would be abundant in:
a. Goblet cells (1mk)
b. Liver cells (1mk)
10. Name the muscle found in
a. Left ventricle (1mk)
b. Oviduct (1mk)
11. State two limitation of fossil records as evidence of organic evolution theory. (2mks)
12. a)A biological washing detergent contains enzymes which ensure stains like mucus and oil from cloth
which are soaked in water with the detergent. Name to groups of enzymes that are present in the
detergent (2mks)
b. Why would the stains be removed faster with the detergent in water at 35° rather than 15°
(2mks)
13. State three ways in which climbing plants obtain support (3mks)
14. Name two structures of gaseous exchange in aquatic plant (2mks)
15. Name the bone that articulate to form a ball and a socket joint at the hip. (2mks)
16. The diagram represents a nerve cell

i. Identify the nerve cell (1mk

ii. Give a reason for your answer (1mk)
b. Use an arrow indicate on the diagram the direction of movement of the impulse of the cell
17. Name the pathogen or microrganism that causes syphilis (1mk)
18. State one use of the following excretory products of plant.
a. tannins (1mk)
b. papain (1mk)
19. Name the blood cell that produces antibodies (1mk)
20. Name the tissues in plant responsible for
a. secondary growth (1mk)
b. Synthesis of carbohydrates (1mk)
21. Name the chemical bond between two amino acids in the protein chain. (1mk)
22. a)Name two organisms that form biological environment of malaria parasite plasmodium
b. Explain why the use of oil on stagnant water as a control measure for spread of malaria is being
discouraged (2mks)
23. Name the cells produced by Cork combium during secondary growth in flowering plant. (1mk)
24. Give two reasons for the lag phase of a sigmoid curve of growth of an organism. (2mks)
25. A patient of blood group B negative was transfused with blood of group o positive after 2 weeks a
similar transfusion was given to the same patient. State the effect in the patient's blood after
a. The first transfusion. (1mk)
b. Second transfusion (1mk)
26. a)Distinguish between egestion and excretion (2mk)
b. State one symptom that is common in diabetes mellitus and diabetes insipidus (1mk)
27. Name the structures involved in the accommodation of the eye (2mks)
28. State the role of the following substances in human nutrition (3mks)
a. Roughages
b. Vitamins
c. Water
29. State the main process that take place in each of the following parts of the mammalian nephron
Page | 168
a. Bowman capsule (1mk)
b. Proximal convoluted tubule (1mk)
30. Distinguish between chemical and mechanical digestion (1mk)
31. State three homeostasis roles of the liver.
32. Make a diagram of a pinnate leaf whose leaflets have serrated margin.
33. A female human being was found to have an extra sex chromosomes in her cells.
a. Give the total number of chromosomes in the female individual cell.
b. Explain possible cause of this condition
c. State one physical characteristics of the female individual with such a condition

Page | 169
 ITHANGA KAKUZI
PAPER 2
231/2
TIME : 2 Hrs
SECTION A (40 MARKS)
Answer all the questions in this section in the spaces provided
1. The diagram below represents a mature bread mould (Rhizopus)

(a) Name the structures P, Q and R (3mks)

(b) What is the function of the structure P? (1mk)
(c) State two economic importance of moulds (2mks)
(d) i) Name the kingdom to which bread mould belong (1mk)
ii) List down one general characteristic of member of the kingdom named in d (i) above.
2. The diagram below represents a longitudinal section through a dicotyledonous root tip.

(a) State the function of the part labeled M (1mk)

(b) State the function of the part labeled N (1mk)
(c) Name the process by which water moves from the soil particles into plant root (1mk)
(d) How is the structure labelled different from that of the stem of the plant. (1mk)
(e) Name the zones labeled Y and Z (2mks)
3. Pure breed of red cows and pure breed of white bulls were crossed to give F1 calves which had a
mixture of red and white coat known as roan. The F1 were selfed.
(a) Using letter R to represent gene for red colour and W to represent gene for white colour work out the
phenotypic ratio of F2. (4mks)
(b) Work out the genotypic ratio of a cross between F1 offspring and white bull. (3mks)
(c) Comment on the gene(s) controlling the colour of coats in cattle mentioned above. (1mk)
4. The quantities of urine passed out per day was established in five animals P, Q, R, S and T of the
same species in their natural habitats. The results were as shown below.
Quantity of urine (dm3)

Animals
a) i) Which of the five animals was likely to be excreting urine very rich in ammonia.

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 ii) Give a reason for your answer in (a) (i) above (1mk)
b) i) Which of the animals was likely to be living in a desert environment (1mk)
ii) Give a reason for your answer in (b) (i) above (1mk)
c) Explain how ingestion of very salty food may affect the quantity of urine produced. (2mks)
5. The diagram below represents a section through the mammalian ear. Study it and answer the
questions that follow.

(a) Name the structures labeled H and J (2mks)

State how the structures labeled H, M and N are adapted to their functions (3mks)
(c) State what would happen if the structure labelled K was completely damaged (1mk)
(d) Name the fluid contained in structure N (1mk)
(e) Apart from hearing, state the other role performed by the human ear (1mk)

SECTION B (40 MARKS)

Answer question 6 (compulsory) in the spaces provided and either question 7 or 8 in the spaces
provided after question 8.
6. The table below shows the population of a housefly Musca domestica which is parasitized by wasps
of species Nasonia Spp. The investigation of their population growth pattern was carried out for 70
weeks. In these experimental space and physical factors were assumed not to be limiting.
Time in weeks 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Musca domestica 40 70 110 260 350 480 400 395 350 40 60 140 250 240 230
Nasonia spp 10 20 30 45 100 200 300 380 410 250 60 20 40 200 280
(a) Using the readings in the table, plot graphs on the same axis of population growth of organisms
against time. (8mks)
(b) Account for the growth of
(i) Musca domestica between 10th week – 25th week (1mk)
(ii) Nasonia species between 40th week – 50th week (1mk)
(c) What is the population of?
(i) Nasonia Spp on the 62nd week (1mk)
(ii) Musca domestica on the 4th week (1mk)
(d) Bemex, another parasite of housefly was introduced into the ecosystem. Giving a reason what will be
the effect on the population of
(i) Housefly Musca domestica (2mks)
(ii) Nasonia Spp (2mks)
(e) In estimating the population of Musca domestica in the experiment above, capture-recapture method
was used. Describe the procedure which was followed. (4mks)
7. Describe the structure and functions of various organelles in a mature animal cell. (20 marks)
8. (a) What is natural selection? (2mks)
(b) Describe how natural selection brings about adaptation of a species of a living organism to its
environment. (18mks)

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 ITHANGA KAKUZI
231/3
BIOLOGY
PAPER 3
CONFIDENTIAL
• Lemon fruit labelled specimen A
• Scalpel
• Small beaker
• Test-tube with about 5ml of raw milk
• Test-tube with about 5ml of fresh lime water
• Plastic straw
• Empty test-tube
• DCPIP solution.

ITHANGA KAKUZI
231/3
BIOLOGY
PAPER 3
1. a) You are provided with specimen A
i) Name the fruit type that the specimen belongs to (1mk)
ii) Make a transverse section on specimen A and label the parts. (4mks)
iii) State the type of placentation of fruit A (1mk)
b) Squeeze out the juice from the two halves of specimen A into a small beaker. Using part of the juice and
the reagents provided only, test for the food substances in the juice. (3mks)
c) Put little amount of juice extracted to the raw milk provided in a test tube and complete the table below
d) Transfer 5ml of lime water in to a test tube. Insert a straw in the lime water in the test tube and blow air in it.
i) State the observation made (1mk)
ii) What was the aim of the experiment? (1mk)
iii) Explain the observation (1mks)
2. a) The photographs below were taken from a grassland ecosystem. Examine them carefully

i) Construct a food chain from the organism in the photographs above. (1 mk)
ii) Name the trophic level occupied by the antelope giving a reason for your answer. (2 mks)
iii) Using observable feature only, name the class in which lion and antelope belong giving a reason.
iv) With a reason, identify which of the three organisms has the highest biomass. (2 mks)

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b) The photographs below show beak structure of some birds, study them and answer questions
that follows

i) What type of evolutionary structures do the beaks represent? (1mk)

ii) Explain your answer above. (1mk)
iii) Describe the Lamark’s explanation on the evolution of these beaks (3mks)
iv) Name the likely diet of the bird A (1mk)
v) Give a reason for your answer (1mk)
3. Use the photographs on plant structures to answer the following questions.

L R

i) Name the plant structure shown in the photographs. (1mk)

ii) Name the part of the plant where the structure shown in the photos is found abundantly in
terrestrial plants. (1mk)
iii) Give the function of the structure named in (i) above. (1mk)
iv) Observe photograph F carefully. Give three structural adaptations of the structure to its functions.
v) Explain what would happen to the plant structures if they are placed in a hypotonic solution.
(3mks)
vi) State three ecological adaptations of above structures for plants found in arid and semi-arid areas
(3mks)

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 ITHANGA KAKUZI JOINT
BIOLOGY
Paper 1
marking scheme
1. Define
a. Niche (1mk)
Specific location and zone of an organism in ecosystem
b. Eutrophication (1mk)
Enrichment of nutrients of water bodies eg. sulphates, nitrates and phosphates leading to growth of
water plants that consume oxygen for aquatic animals
2. Name the part of the eye where image is formed (1mk)
Retina
3. State two structural similarities between mitochondrion and chloroplast (2mks)
Both double membranes
Have enzymes to catalyses reaction
4.
a. State the observation that was made (1mk)
Leaf retained brown color of iodine
b. Account for the observation (2mks)
Glycerine blocked stomata hence Carbon IV oxide could not diffuse into chloroplast hence no
photosynthesis to form starch
5. Study the diagram below and answer the question that follows
a. Identify the type of plant-based on habitat (1mk)
Xenophyte
b. Give two reasons for your answer in above (2mks)
succulent tissues
Leaves reduced to spines
c. Explain stomata modification you would expect to be found in the plant (2mks)
i) Sunken stomata to reduce transpiration
ii) Reverse stomata rhythm to reduce transpiration
iii) Meet the stomata closed to reduce transport
6. During oxidation of certain food substance the respiratory quotient was found to be 0.718
a. Name that type of food substance being oxidized (1mk)
Lipids
b. State two advantages of using food substances named (2mks)
Yields a lot of energy
Rich source of metabolic water
c. Give reason why it is difficult to calculate respiratory quotient RQ in plants (1mk)
Plants use some of the respiratory gases
d. Give one reason why knowledge of respiratory quotient is important (1mk)
Give the type of respiratory substance
Give the type of respiration
7.
a. Name the form of nitrogenous waste likely to be in organisms D? Explain (2mks)
Ammonia toxic- required a lot of water to eliminate
b. Organism C explain (2mks)
Urea less toxic does not require a lot of water to eliminate
8. Explain why advisable to breathe through the nose rather than the mouth in human (2mks)
Nosehas hair traps dust
Have blood capillaries to warm air
Have goblets cells to release mucus to trap dust
9. Name organelle that would be abundant in:

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a. Goblet cells (1mk)
Golgi apparatus
b. Liver cells (1mk)
Mitochondria
10. Name the muscle found in
a. Left ventricle (1mk)
Cardiac
b. Oviduct (1mk)
Smooth
11. State two limitation of fossil reveal as evidence of organic evolution theory. (2mks)
Decompose scavenged distorted due to sentimention
Missing links destroyed by tectonic movement
12. a)A biological washing detergent contains enzymes which ensure stains like mucus and oil from
cloth which are soaked in water with the detergent. Name to groups of enzymes that are present in
the detergent (2mks)
Lipases
Proteases
c. Why would be the stains be removed faster with the detergent in water at 35° rather than 15°
35° c is optimum /favorable for enzyme activity. Enzymes will be more active leading to faster stain
removal.
13. State three ways in which climbing plants obtain support (3mks)
Used tendrils
Twine around other plants
14. Name two structures of gaseous exchange in aquatic plant (2mks)
Stomata
Lenticels
Pneumatophores
15. Name the bone that articulate to form a ball and a socket joint at the hip. (2mks)
Femur & pelvic girole
16. The diagram represents a nerve cell
i. Identify the nerve cell (1mk)
Sensory neurone
ii. Give a reason for your answer (1mk)
Cell body off the axon
b. Use an arrow indicate on the diagram the direction of movement of the impulse of the cell
17. Name the pathogen ormicro organism that causes syphilis(1mk)
Treponema pallidum
18. State one use of the following excretory products of plant.
a. tannins (1mk)
Treating leather, manufacturing ink cosmetic, henna feet decoration.
b. papain (1mk)
meat tenderiser
19. Name the blood cell that produces antibodies (1mk)
Lymphocyte, NBreject white blood cells.
20. Name the tissues in plant responsible for
a. secondary growth (1mk)
Cambium accept vascular cambium cork cambium
b. Synthesis of carbohydrates (1mk)
Polisade mesophyll/ spongy mesophyll
21. Name the chemical bond between two amino acids in the protein chain. (1mk)
Peptide
22. a)Name two organisms that form biological environment of malaria parasite plasmodium (2mks)

Page | 175
 Female anopheles mosquito
Human monkey or bird
c. Explain why the use of oil on stagnant water as a control measure for spread of malaria is being
discouraged (2mks)
Leads to water pollution
Destroy aquatic organisms
23. Name the cells produced by Cork combium during secondary growth in flowering plant. (1mk)
Cork cells/ secondary cortex
Parenchyma
24. Give two reasons for the lag phase of a sigmoid curve of growth of an organism. (2mks)
Number of dividing cells is low
Cells yet to adjust to the environment
25. A patient of blood group b negative was transfused with blood of group o positive after 2 weeks a
similar transfusion was given to the same patient .State the effect in the patient's blood after
a. The first transfusion. Stimulate formation of anti-Rhesus antibodies (1mk)
b. Cause agglutination/cloting of donor red blood cells.
26. a)Excretion is the removal of toxic materials, waste products of metabolism and excess substances
from organisms. Egestion is the removal of ingested $ indigestible food substance from food vacuels
and alimentary canal of animals
c. Production of large amount of urine (diuresis) chronic feeling of thirsts
27. lens, ciliary muscle, suspensory ligaments.
28. State the role of the following substances in human nutrition (3mks)
a. Roughages promote peristalsis by adding bulk to food
b. Vitamins influence intake of vitamin D, calcium involved in metabolic reaction
c. Water solvent of transport of digestive products hydrolyzed food substance
29. State the main process that take place in each of the following parts of the mammalian nephron
a. Bowman capsule (1mk)
Utra filtration
b. Proximal convoluted tubule(1mk)
Selective reabsorption
30. Mechanical digestion involves physical breakdown of large food marterial to make smaller pieces
which can be acted upon by enzymes. Chemical digestion is breakdown of food in the alimentary
canal by digestive enzymes to a form that can be absorbed and assimilated to body organs.
31. Thermoregulations
Blood sugar regulation
Protein amino acid fat
32. Compound, pinnate & serrated
33. A female human being was found to have an extra sex chromosomes in her cells.
a. 47
b. Non-disfunction/ failure of chromosome to separate in anaphase 1 or failure of sister chromosomes
to separate in anaphase 2 leading to an extra X chromosome in a cell with XXX instead of XX
34. Signs of obesity
Flat feet
Taller than average female
Infertile
Ovary abnormalities
Widely spaced eyes

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 ITHANGA KAKUZI
231/2
BIOLOGY
PAPER 2
MARKING SCHEME
1. a) P – sporangium;
Q – spore;
R – rhizoids;
b) Formation of spores;
c) i) Causes decomposition of dead matter thus releasing nutrients to the soil to increase
its fertility;
ii) Destroy old cloths/ shoes/ timber;
iii) Causes food spoilage; (mark first two)
d) i) Fungi;
ii) - They lack chlorophyll;
- Has cellwall made up of chitin instead of cellulose; (chitinous cellwall)
- Store carbohydrates as glycogen; (mark first one)
2. a) K – phloem;
L – xylem;
M – root hair;
b) Protects the apical meristem as the root is pushed into the soil;
c) Osmosis;
d) L is centrally located in the root while in the stem is arranged in a ring.
Acc. Xylem is centrally placed in the root while in the stem it is arranged in a ring;
e) Y – region of cell division;
Z – region of cell elongation/ enlargement;
3. a) Parental Genotype (F1) RW x R W;

Gametes W ;
R W R

;(Fertilization) ✓

RR RW RW W W;
F2 genotypes

Phenotypic ratio: Red : Roan : White;

1: 2 : 1
NB: Rej. 1 : 2 : 1 only / Rej. Ratio only.

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b) Parental genotypes RW x W W;

Gametes
R W W W
;

fusion;

RW RW WW WW
Genotype  1mk
Genotypic RW :WW
Ratio 1 : 1;  1mk Rej. Ratio only.
c) Gene for red colour coat and white colour coat are co-dominant/ have equal dominance
acc. Incomplete dominance
4. a) i) Q;
ii) Ammonia requires a lot of water for dilution hence production of large volumes of
dilute urine;
b) i) S;
ii) Excretes small volumes of (concentrated ) urine;
c) Nephron of Q Nephron of S
- Shorter loop of henle - Longer loop of henle;
- Larger glomeruli - Smaller glomeruli;
Rej. short/long nephron.
d) Increases osmotic pressure of blood;
leading to increased water reabsorption (by osmosis) from glomerular filtrate; hence
production of small volumes of concentrated urine; Total 3, max 2 marks
5. a) H – Eustachian tube;
J – Semi-circular canals;
b) H – Tube open/ connection to the phalynx and to the middle ear/ opens during swallowing/
yawning and vomiting to equalize the air pressure in the middle ear with the atmospheric
air pressure;
M – (pinna) curved/ funnel shaped to receive or collect and direct sound waves into the
ear;
N – (cochlea) – long/highly coiled/ spiral in form to increase surface area for sound
perception;
- Has sensory hairs/ cells which convert sound vibrations to impulses/ generate impulses;
- Has endolymph to transmit vibrations;
Mark one for each structure.
Rej. If the adaptation is not tied to function.
c) Total deafness;
d) Endolymph;
e) Balance; acc body balance/ posture.
6. a)
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 Axes 2;;
Scale 1;
Plotting 2;;
Curve 2;;
Curve identity 1;
b) i) Population increases rapidly because of fewer predators/ less predation;
ii) Population decreases/ declines/ reduces due to shortage of food/ inadequate supply
of food/ few number of prey;
𝑐𝑐)𝑖𝑖)100 ± 1;
𝑖𝑖𝑖𝑖)65 ± 1;
d) i) Population decreases/reduces; due to many predators;
ii) Population decreases / reduces; due to competition over the same food source;
(interspecific competition)
e) Using a sweep net the houseflies were caught, marked using ink that cannot be erased easily counted
and recorded; The flies were then released to the population. After 24 – 48 hours the procedure was
repeated the flies in the second capture counted and recorded;
𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹 𝑥𝑥 𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐
𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜 = ;
𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟
7. Mitochondria;
Has a double membrane surrounding it and inner membrane folded to form cristae which increases the
surface area for attachment of respiratory enzymes
Golgi body/apparatus; are stack of membrane bound like sac/is a system of membranes sacs/hollow
spaces; that transports glycoproteins/carbohydrates and proteins; They package glycoproteins; secrete
mucus/enzymes/synthesized proteins.
Lysosomes;
Are spherical in shape and enclosed by a single membrane; contain hydrolytic enzyme which destroy
worn out organelles, micro-organism/ingest food/breakdown large molecules.
Endopasmic reticulum;
Are membrane bound cavities in cytoplasm; smooth endoplasmic reticulum site for lipid/sterot
transport.
Rough endoplasmic reticulum ahs ribosome on its surface; and transport proteins.
Centrioles;

Page | 179
 Rod shaped; located outside the nuclear membrane, for formation of fibs and cilia
Cytoplasm;
It’s a fluid medium; where chemical reaction occurs, contains organelles and inclusions
(e.g. glycogen granules, fat droplets and dissolved substances).
Cell membrane;
Encloses all cell organelles; has phosplipid layer between two protein layers/it’s a lipoprotein
layer has pores that selectively allows substances to pass in and out of the cell/its semi
permeable.
Nucleus;
Has a double membrane/nuclear membrane around it, which has pores to allow substances in
and out of the nucleus; Has nucleoplasm, which contain nucleolus/chromatin, nucleus controls
all cell activities, Nucleolus manufactures ribosomes and centrioles.
Ribosomes;
Are spherical in shape and suspended in cytoplasm and attached on endoplasmic reticulum;
synthesis proteins. Max 20 marks
8.
a) Nature selects those individuals/ organisms which are sufficient/ well adapted and allows
them to survive; and rejects those that are poorly adapted by wiping them out;
b)
- Individuals of the same species show variations; that are caused by genes;
- The variations can be passed from parent to offspring; through genetic inheritance; some of the
variations become more suited to the prevailing environmental conditions;
- Most organisms produce more offspring than the environment can support; hence there is always a
struggle for existence; due to competition among individuals for scarce resources;
- Individuals posses traits/ characters that enable them to have competitive advantage to survive /
stand better chances to survive in the struggle; in the end the well adapted/ suited individuals
survive; and reach reproductive age; and pass over their favourable traits to their offspring; since
survival is of the fittest;
- Poorly adapted individuals/ those without favourable traits perish/ die; and fail to reach sexual
maturity/ reproductive age; hence do not pass their traits to their offspring (don’t reproduce); the
fittest individuals only survive; After many generations there is an accumulation of favourable
genes/ traits; well suited to the environment.
Total 20

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 ITHANGA KAKUZI JOINT
BIOLOGY
Paper 3
marking scheme
1. a) i) Berries.
ii)

iii) Axile rej axil

b)
Procedure Put little amount of DCPIP solution in a test-tube
Add juice extracted from specimen A drop by drop while shaking
Observation The DCPIP solution is decolorized
Conclusion Vitamin C or ascorbic acid present
c)
Observation The milk turns into curds/ white precipitate formed
Explanation Ascorbic acid causes raw milk to coagulate or clot or form curds as it
converts soluble milk protein (caseinogen) to insoluble milk protein
(casein).
d) i) White precipitate is formed.
ii) To investigate the gas exhaled/expired by mammals.
ii) Calcium hydroxide + Carbon (iv) oxide → calcium carbonate + water
2. a) i) Grass → Antelope → Lion
ii) Primary consumer since it feeds on producers or grass
iii) Mammalia since they possess mammary glands, their body is covered by hair or fur.
iv) Grass since it is the producers.
b) i) Homologous structures
ii) The structures appear to be of same ancestry origin but have evolved to perform same function.
iii) Organ development in terms of size and shape has a direct relationship to their employment:
use and disuse. Therefore these beaks developed into various shapes and sizes due to
environments they exploit and were later inherited by subsequent generation through
reproduction.
iv) Flesh or meat
v) The beak is sharp, pointed and curved
3. i) Stoma ii) Leaf iii) Site for gaseous exchange and transpiration.
iv) Surrounded by bean shaped guard cells which have thick inner wall and thin outer wall hence
opens when turgid and closes when flaccid.
Located on the leaf epidermis so as to access air in the atmosphere easily.
Guard cells contain chloroplasts which carries out photosynthesis producing sugars.
v) They would gain water by osmosis, become turgid and therefore opens.
vi) They are small in size to reduce amount of water lost through transpiration.
They are located in pits to ensure high water moisture in sub-stomatal air space hence
reducing transpiration.
They are few to reduce water lost by transpiration.
They exhibit reversed stomatal rhythm hence opening at night and closing during the
day to reduce rate of transpiration.

Page | 181
 SUNSHINE
231/1
PAPER 1
2 HOURS
1. Name the characteristic of living organisms illustrated by each of the activities described below:
(a) Dressing heavily (1 mark)
(b) Bursting of the sporangium in rhizopus sap. (1 mark)
2. Give a reason why an aeroplane is not classified as a living organism even though it can move from
place to place, take in oxygen and release carbon (IV) oxide. (1 mark)
3. (a) Define the term species. (1 mark)
(b) A lion and a leopard belong to the same genus; Panthera. Explain why if interbred, they give
rise to a sterile offspring. (1 mark)
4. A student carried out an experiment on a light microscope. The field of view was as shown in the
following diagram. Below when the millimetre scale of a ruler is placed on the stage across the field
of view.

If she counted 20 cells on the diameter of the same field of view, what was the approximate size of
each cell in micrometres (um). Show your working. (2 marks)
5. Study the following diagram and answer the questions that follow.

P
(i) Identify the organelle. (1 mark)
(ii) State the function of the organelle labelled P. (1 mark)
6. The diagram below shows an open stoma. Study it and answer the questions that follow.

(a) Identify the specialised cell labelled P. (1 mark)

(b) Explain how increase in light intensity enhances the opening of the stomata. (2 marks)
7. Tuberculosis is a respiratory disease resulting from bacterial attack on the alveoli. Name the bacteria
that cause tuberculosis. (1 mark)
8. Below is an equation showing aerobic breakdown of a certain food substance.
C18H36O2 + 26O2 →18CO2 + 18H2O
Page | 182
(a) Calculate the respiratory quotient of the food substrate. (1 mark)
(b) Name the likely food substrate oxidised. (1 mark)
9. Lipids produce more energy per gram than carbohydrates and proteins. However, body cells prefer
carbohydrates as the main respiratory substrate. Give two reasons for this. (2 marks)
10. The diagram below shows the flow of electrical excitation on the cardiac muscle.

Identify the region of the region of the right atrium labelled R and state its role. (2 mark)
11. State one characteristic of blood capillaries that aid each of the following processes:
(i) Ultrafiltration (1 mark)
(ii) Diffusion (1 mark)
12. A student mounted a transverse section of a plant organ on a microscope and made a diagram of his
observation as follows.

(a) Identify the organ. (1 mark)

(b) Give one physiological role and one structural role of part T. (2 marks)
(i) Physiological role
(ii) Structural role
13. What is the structural role of osmosis in plants? (1 mark)
14. Diagram below shows an organism undergoing a certain biological process. Study it and answer the
question that follows:

(i) Identify the process represented above. (1 mark)

(ii) Given an environmental condition that is necessary for the above process to occur. (1 mark)
(iii) Name the part labelled X. (1 mark)

Page | 183
15. Below is a diagram of a cell undergoing the process of mitosis.

(i) Identify the stage of cell division shown. (1 mark)

(ii) Give a reason for your answer in (i) above. (1 mark)
16. (a) i) Define the term fertilisation. (1 mark)
ii) Differentiate between external and internal fertilisation. (2 marks)
(b) State the function of sertoli cells in male reproductive system. (1 mark)
17. Name the tissues that are responsible for: (2marks)
(a) (i) primary growth in plants
(ii) secondary growth in dicotyledonous root
(b) Explain why secondary growth does not take place in grass plant. (1 mark)
18. (a) Name the important products formed in the light stage of photosynthesis. (2 marks)
(b) Other than carbohydrates name three other food substances manufactured during
photosynthesis. (2 marks)
19. Name three processes in organisms that depend on active transport. (3 marks)
20. The following photographs represent jaws and dentition of different heterotrophy. Study them and
answer the questions that follow.

(i) Identify the mode of nutrition of organism represented in photograph U and W. (2marks)
(ii) Give two reasons for your answer for photograph W above (2 marks)
21. Polyploidy has been quite useful in plant breeding especially in wheat farming. State three benefits
of polyploidy to a farmer. (3 marks)
22. Evolution is a focal point on scientific investigation into the nature and origin of life. What is
evolution? (1 mark)
23. What is meant by the term natural selection? (2 marks)
24. Give an example of vestigial structures in man. (1 mark)
25. Name the type of response exhibited by spirogyra when it moves towards the source of light.
(1 mark)
26. State two differences between tropisms and taxes. (2 marks)
27. Define response. (1 mark)
28. (a) State the necessity of support to a passion (Passiflora edulis) plant? (2 marks)
(b) How would plants compensate for their inability to move about? (2 marks)
29. Give two structural differences between skeletal and smooth muscles (2 marks)
30. Name the special cartilage that separate two vertebral bones? (1 mark)
31. An accident victim visited a neurologist while complaining of loss of balance, memory loss and
persistently not able to sleep. Name the parts of the brain that may have been affected linking each
with possible findings by the neurologist. (3 marks)
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 Symptoms Parts of the brain affected as diagnosed by the neurologist
Loss of balance
Loss of memory
Persistently remaining Awake

32. Name a special structural feature in a nerve cell that distinguishes motor neurons from sensory
neurons ( 1 mark)
33. The diagram below represents a certain plant.

a) What is the likely habitat of the plant? (1 mark)

b) Give two reasons for your answer in (a) above (2 marks)
34. Specimen’s J, K and L are photographs of animals. Specimen’s J and K belong to same phylum.

L J K
i. Using observable features, state the phylum of specimen J and K. (2marks)
Phylum………………………………………………………………………………
Features……………………………………………………….………………………
ii. Using observable features only, state the class to which the photograph of specimen L belong.
(2marks)
35.
a) what the advantages of desert animals excreting their nitrogenous waste in form of urea and not
ammonia (2marks)
b) Explain one modification on the kidney nephron of desert mammals (2marks)

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 SUNSHINE
231/2
BIOLOGY
PAPER 2
TIME: 2 HOURS
SECTION A [40 marks]
Answer all questions in the spaces
1. a) State Mendel’s first law of heredity. (1 mark)
b) In maize the gene for purple colour is dominant to the gene for white colour. A pure breeding
maize plant with purple grains was crossed with heterozygous plant.
i. Using letter G to represent the gene for purple colour. Work out the genotype ratio of the
offspring. (4 marks)
ii. State the phenotype of the offspring. (1 mark)
iii. State two causes of discontinuous variation. (2 marks)
2. A student set up an experiment with four sets of polled bean seedlings which were 4 days old.
Set up A Adequate supply of sunlight and left in the open
Set up B In a carton box with an opening on one side to allow light in
Set up C Placed in a klinostat and covered with a carton box and an opening in one side
to allow light
Set up D In a carton box and completely covered
The set ups were left for four days. The soil in each set up remained watered throughout.
Observations were then made.

(a) State your observation for set ups B, C, D (3 marks)

(b) Explain the observations made on set up B. (2 marks)
(c) What is the purpose of set up A and C? (1 mark)
(d) Explain the observations made onset up C. (1 mark)
(e) Name the phenomenon shown by the seedlings in set up D. (1 mark)
3. A form two student set up the apparatus as shown in the diagram below.

(a) What is the aim of the experiment? (1 mark)

(b) State the observation made in the test tube and the boiling tube. (2 marks)
(i) Test tube
Page | 186
(ii) boiling tube
(c) Account for the observations made in b(i) and (ii) above. (2 marks)
(i) Test tube
(ii) boiling tube
(d) Write a word equation for aerobic respiration. (1 mark)
(e) Give two factors that affect the rate of respiration. (2 marks)
4. Below is an illustration showing the mechanism of blood sugar regulation in the body. Use it to
answer the following questions.

(a) State the process that occurs in the ileum that can lead to an increase in glucose level.
(1mark)
(b) What type of feedback mechanism is represented by H? (1mark)
(c) State three corrective mechanisms carried out at G. (3marks)
(d) Name the condition that may result from further excess. (1mark)
(e) Name the hormone that would be responsible for correcting the deficiency. (1mark)
(f) What is the disadvantage of low blood glucose level in blood. (1mark)
5. (a) Distinguish between pyramid of numbers and pyramid of biomass. (2 marks)
(b) From an ecological study, students formed the following food web.

From the food web, construct two food chains with lizard as a tertiary consumer. (2 marks)
(c) i) Which organism has the least biomass in the ecosystem. (1 mark)
ii) Give reasons for your answer. (3 marks)
(d) What happens if a pesticide that kills caterpillars only was applied on the habitant? (1 mark)
SECTION B [40 marks]

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 Answer question 6 (Compulsory) and either question 7 or 8.
6. A botanist carried out an experiment to find out the relationship between transpiration and absorption
of water in a maize plant growing in a natural habitat. The results were as shown below.

Time of day Amount of water lost by Amount of water absorbed

transpiration (mm) (mm)
0900 hrs – 1100 hrs 30 17
1100 hrs – 1300 hrs 43 27
1300 hrs – 1500 hrs 49 39
1500 hrs – 1700 hrs 43 43
1700 hrs – 1900 hrs 22 29
1900 hrs – 2100 hrs 13 17
2100 hrs – 2300 hrs 05 12
2300 hrs – 0100 hrs 01 08

(a) On the same grid. Plot a graph of the amount of water lost through transpiration and the amount of
water absorbed against time of day. (7 marks)
(b) At what time of day was the amount of water absorbed and the amount of water lost through
transpiration equal? (1 mark)
(c) Account for the rate of transpiration between the following time intervals 0900 – 1100 hrs to 1300 –
1500 hrs. (3 marks)
(d) Explain how sprinkling salt around the base of the maize plant may affect the rate of absorption of
water. (3 marks)
(e) Identify the physiological process responsible for absorption of water by root. (1 mark)
(f) Give two environmental factors that affect the rate of transpiration. (2 marks)
(g) Name the instrument used to measure the rate of transpiration. (1 mark)
(h) List two types of transpiration in terrestrial plants. (2 marks)
7. a) Describe adaptations of the ileum to its functions. (10 marks)
b) Discuss the conditions that are necessary for germination to take place. (10 marks)
8. a) Discuss the role of hormones in menstrual cycle. (10 marks)
b) Using named structures, explain how terrestrial plants achieve support? (10 marks)

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 SUNSHINE
231/3
PAPER 3
TIME: 1¾ HRS
CONFIDENTIAL REQUIREMENTS
• Tilapia labeled Q
• Pair of forceps
• 30 cm ruler
• Wheat flour labeled Q
• Maize flour labeled R
• 10% sodium hydroxide solution
• 1% copper (II) sulphate solution
• Five test tubes
• Test tube rack
• Measuring cylinder
• Two droppers
• Distilled water

SUNSHINE
231/3
PAPER 3
1¾ HOURS
1. A. You are provided with specimen Labelled Q (tilapia) and a pair of forceps. Using a pair
of forceps stroke the specimen from the head to the tail, repeat this procedure from the
tail to head
i. Record your observations below as: (2 marks)
a) Head to tail
b) Tail to head
ii. State the significance of your observations in (i) above? (1 mark)
iii. Using a ruler measure the length of the specimen Q as follows
a. Length from tip of mouth to tip of tail …………….. cm
b. Length from anus to tip of tail ……………………. cm (1 mark)
c. Calculate the tail power using the measurements obtained in iii (a and b) above? (1 mark)
iv. Name the structures in the specimen Q that adapts to: (2 marks)
(a) Prevent pitching
(b) Prevent yawning
B. You are provided with photographs C and D obtained from a terrestrial mammal. Study them
carefully and answer the questions that follows:

Photograph C Photograph D
a) Identify the bones represented by the photographs labelled C and D (2 marks)
Photograph C

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 Photograph D
b) Name the bone and a joint which articulates with Photograph D at the proximal end?
Bone
Joint (2 marks)
c) How bone labelled X in photograph C suited to perform its function? (1mark)
d) Name the type of skeleton found in members of the phylum Arthropoda. (1 mark)
2. The photographs below show specimens of different types of fruits. Examine them

A B

C D

E F

a) State two differences between specimens E and C. (2marks)

b) Name the type of placentation shown by specimens. (2marks)
i) C
ii) B
c) Giving reasons, state the mode of dispersal for each specimen in the table below. (6marks)
Specimen Mode of dispersal Reason
A
D
F
d) With a reason identify the type of fruit shown by B. (2marks)
e) On the diagrams A label any two parts. (1mark)
3. a) You are provided with substance Q and substance R.
Using the reagents provided, carry out food tests on the substances and record your work in the table
below.
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 Note: Before carrying out the procedure, place a small quantity of the substance in a test tube; add a
little amount of water and shake to make a suspension. (8marks)

Food Procedure Observations Conclusion

To 2ml of Q add 3 drops of iodine solution and mix
To 2 ml of Q add sodium hydroxide solution followed by
a few drops of copper(II) Sulphate solution
To 2 ml of R, add 3 drops of iodine solution and mix
To 2ml of R add some sodium hydroxide solution
followed by a few drops of copper (II) Sulphate solution

b) i) Which of the two substances should be included in a diet to protect a child from suffering from
kwashiorkor? (1mark)
ii) Give a reason for your answer in b (i) above. (1mark)
c) Name two enzymes in the human body which digest the food substances found in Q. (2marks)
e) State the organ from which each of the enzymes you have stated in c (i) above acts. (2marks)

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 SUNSHINE SCHOOL
BIOLOGY
PAPER 1
MARKING SCHEME
1. a) irritability/sensitivity
b) Reproduction
2. Aeroplane does not reproduce
Airplane does does not respond to stimuli
Does not grow and develop
3. a) Smallest taxonomic unit of classification whose members have similar characteristics,
hereditary distinction and can naturally interbreed
b) Lion and leopard belong to different species
diametr of the field view
4. Cell diameter
number of cells along the diameter
6 × 1000
= 300µm
20
5. i) Rough endoplasmic reticulum
ii) synthesis of proteins
6. a) guard cell
b) Increased light intensity increases the rate of glucose synthesis(photosynthesis) which
increases the osmotic pressure of guard cells which then drain more water become more
turgid.
7. Mycobacterium tuberculosis
amount of carbon(IV)oxide produced
8. a) Respiratory quotient=
amount of oxygen used
18
= 0.692 = 0.7
26
b) Lipid
9. Carbohydrates are easily soluble
Carbohydrates requires less oxygen to oxidize/break down.
10. Sino Atrial Node
Initiates excitation of cardiac muscles
1. i) Narrow lumen
ii) Thin walled
12. a) Root
b) i) conduction of water and dissolved mineral salts
ii) Mechanical support
13. Enhances support by making plant cells turgid
14. i) Budding
ii) Moisture
Glucose
Bud
15. i) Metaphase
ii) chromosomes are aligned at the equator of the spindle
16. a) i) Fusion of nuclei of male and female gametes
ii)
External fertilization Internal fertilization
Gametes fuse outside the body of the female Gametes fuse inside the female’s body
More eggs are produced to increase survival chances Less eggs/ova are produced
b) Nourishment of sperm cells
17. a) Apical meristems

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 b) Cambium meristem
18. a) Hydrogen atoms
Adenosine triphosphate
b) Proteins
Vitamins
Oils
19. Absorption of digested food in the ileum
Reabsorption of sugars and salts in the kidney tubules
Absorption of mineral salts by plant roots
20. i) U- carnivorous
W-herbivorous
ii) Diastema for food manipulation by the tongue
Hard/horny pad on the upper jaw a surface for cutting food
21. Early maturity
High yield
Pest and disease resistance
Drought resistance
22. Gradual change from pre-existing life forms to complex life forms over a long period of time
23. A phenomenon where nature selects organisms with adaptive variations such that they survive
to reproductive maturity and pass the adaptive variations to their offspring while the
Less adapted perish
24. Coccyx
25. Positive phototaxis
26.
Tropism Taxes
Growth curvature Locomotory responses
Slow Rapid
Not controlled by hormones Controlled by hormones

27. Change in behavior of an organism due to a stimulus

28. a) Exposes leaves to the sun for photosynthesis
Exposes flowers to agents of pollination
b) Cross pollination
Efficient seed and fruit dispersal mechanisms
Photosynthesis
29.
Skeletal Smooth muscle
Cylindrical shaped Spindle shaped
Multinucleated Uninucleated
30. Intervetebral disc
31.
Symptoms Parts of the brain affected as diagnosed by the neurologists
Loss of balance Cerebellum
Loss of memory Cerebrum
Persistently remaining awake Thalamus
32. Motor neurons have a terminal cell body inside central nervous system
33. (a) Arid/semi-arid/dry
(b) Succulent stem to store water
Leaves reduced to thorns

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34. i) Arthropoda
Jointed appendages
ii) Mammalia
Body covered by fur
35. a) Urea is less toxic than ammonia hence require less water to eliminate thus help in water
conservation.
b) long loop of Henle to increase surface area for reabsorption of water
Small glomeruli to reduce surface area for ultrafiltration

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 SUNSHINE SCHOOLS
BIOLOGY
PAPER 2
MARKING SCHEME
SECTION A
1. a) Characteristics of an organisms are controlled by hereditary factors which occur in pairs.
Only one of the pairs of factors can be represented in a single gamete.
b) i)Parentalphenotype purple grains purple grains
Parental genotype GG Gg
Gametes G G G g

F1 genotype GG Gg GG Gg

Purple
ii) Purple
iii) Mutation
Gamete formation- crossing over and independent assortment
2. a) B-shoots/seedlings curved towards light
C-shoots grew vertically/straight
D-etiolation/seedlings became etiolated
b) light from one end caused auxins to move to the opposite darker side where they
stimulated faster cell division and elongation/ faster growth causing the shoot to curve
towards light.
c) Control experiment
d) Clinostat cancelled the effect of unidirectional light hence auxins remained evenly
distributed leading to uniform growth.
e) Etiolation
3. a) To show that carbon (IV)oxide is released when food is oxidized/burnt.
b) i) White precipitate
ii) Anhydrous cobalt chloride turns from blue to pink
c) i) carbon (IV)oxide produced reacts with lime water/ calcium hydroxide to form
insoluble calcium carbonate.
ii) Water vapour produced hydrates cobalt chloride causing change from blue to pink.
d) Glucose + Oxygen → carbon(IV)oxide + water +energy
e) Glucose/substrate concentration
Oxygen concentration
Temperature
Enzymes
4. a) Absorption
b) Positive feedback
c) Under the influence of insulin, excess glucose is converted by liver into: Glycogen, fats,
increased glucose oxidation
d) Diabetes mellitus
e) Insulin
f) Inadequate respiratory substrate for body cells
Too low osmotic pressure which may result to haemolysis
Page | 195
5.
a) Pyramid of numbers is the diagrammatic representation of the number of organisms at each
trophic level while pyramid of biomass is the diagrammatic representation of total dry mass of
organisms at every trophic level
b) Green plants → small insects → lizard
Recycling leaves → small insects → lizard
Recycling leaves → caterpillar → lizard
c) i) Hawk
ii) Energy loss between trophic levels in form of heat
Occupies the highest trophic level hence least in number
d) Number of lizards decrease/decline.
SECTION B
6.(a)

b) 1500-1700hours
c) Rate of transpiration increases during the time interval due to increase in temperature which
increases the rate of evaporation that results to increased saturation deficit and due to light
intensity which leads to opening of the stomata.
d) Salt dissolves in moisture increasing the osmotic pressure of the surrounding soils. This results
to reduced uptake of water by root hair cells due to their lower osmotic pressure than the
surrounding water.
e) Osmosis
f) Temperature
Humidity
Atmospheric pressure
Wind
Light intensity
g) photometer
h) Stomatal transpiration
Lenticular transpiration
Cuticular transpiration
7. a)Long to provide a large surface area for absorption
Narrow to ensure contact with digested food
Highly coiled/folded to slow down moving food and increase time for absorption
Have numerous villi and microvilli on inner surface to increase surface area for absorption

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 Thin epithelial lining to reduce diffusion distance for food
Dense capillary network in villi for absorption of glucose and amino acids
Goblet cells on epithelial membrane to secrete mucus that ease movement of food
Crypt of Lieberkühn between bases of villi that secrete intestinal juice.
b) i) Environmental/external;
Water-water is necessary for:
• Softening of hard seed coat for plumule and radical to emerge.
• Activation of germination enzymes
• Medium for transport of hydrolyzed food.
• Medium for enzymes to act on the food
• Hydrolyzes and dissolves stored food in seed
Oxygen- oxidation of stored food to produce energy
Optimum/favourable temperature-for maximum enzyme activity. To low temperature below
optimum deactivate enzymes while too high temperature above optimum denature enzymes
Internal conditions
Enzymes-for hydrolysis of stored food e.g. protease for proteins, diastase for carbohydrates,
lipase for lipids.
Hormones-gibberellins and cytokinins stimulate germination
Viability-embryo of seed must be alive and healthy
8. a)
New cycle begins immediately onset of discharge of tissue debris;
 Anterior lobe of the pituitary gland secretes Follicle Stimulating Hormone (F.S.H) which
Stimulates development of graafian follicle in the ovary
 Accumulates and stimulates ovaries to secrete Oestrogen
Oestrogen has the following effects;
 Induces healing and repair of uterine walls.
 Accumulates to stimulates anterior pituitary gland to secrete luteinizing hormone (L.H)
Luteinizing hormone has the following effects;
 Stimulates maturation of the graafian follicle in the ovary
 Stimulates bursting of graafian follicle in the ovary
 Stimulates formation of corpus luteum from remains of graafian follicle. The corpus luteum the
produce progesterone
Progesterone stimulates thickening and blood supply to the endometrium in readiness for
implantation.
If fertilization occurs, corpus luteum remains intact hence the level of progesterone increases
which inhibits production of F.S.H hence graafian follicle does not develop hence no ovulation.
If fertilization occurs corpus luteum disintegrates and no more progesterone is produced. A drop
in progesterone leads to disintegration of endometrium which marks the beginning of a new
cycle.
b) Use of tendrils to twine around other plants that have stronger stems
Use of hooks to hold onto stronger stems and other objects
Parenchyma cells on cortex and pith provide support through turgidity and packing in
herbaceous plants
Collenchyma cells; their walls are thickened with cellulose especially at the corners to provide
mechanical support.
Sclerenchyma cells; consists of dead cells thickened by lignin to provide mechanical support.
Xylem vessels and tracheid
Vessels are thick walled tubes with lignin deposits on the walls. Thick lignified walls give
strength and mechanical support to the plant.

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 MANGU
PAPER 1
TIME: 2 HOURS
231/1
QUESTIONS
1. a) Lietego school biology student used a microscope with X40 objective lens and X5 eye piece lens
which had 2mm radius.
Calculate the area of the field of view in micrometers. (2mks)
b) What is the average size of the cell in micrometers if there were 5 cells on the field of view
(2mks)
2. State three differences between osmosis and active transport. (3mks)
3. The lungs and ileum are adapted for absorption .State three features they have in common which
facilitate absorption. (3mks)
3. The figure below represents a structure obtained from the ileum of a mammal.

a) Give the identity of the structure. (1mk)

b) What is the importance of the structure named in (a) above? (1 mk)
c) Name the parts labeled A, B and D. (3mks)
d) i) Name the juice secreted by the part labeled C. (1mk)
ii) List two enzymes present in the juice named in d (i) above. (2mks)
5. Below is a diagrammatic summary of the main biochemical events in photosynthesis. Studyit
carefully and answer the questions that follow.

Molecul

a) Suggest the identify of molecule P. (1mk)

b) Name the gases represented by the letters Q, W (2mks)
c) Name the specific site for the reactions in stage B (1mk)

Page | 198
d) Name reaction Z. (1mk)
6. (a) What is the importance of the following substances in blood clotting process in man?
(i) Vitamin K: (1mk)
(ii) Thrombin: (1mk)
(b) Comment on:
(i) Disadvantage of having blood group O. (1mk)
(ii) Advantage of having blood group AB. (1mk)
7. (a) State the reasons for the following adaptations of the xylem vessels. (2mks)
(i) Narrow lumen:
(ii) Lack of cross walls:
(b) State two distinguishing features of the phloem sieve tubes. (2mks)
8. a) State two functional differences between arteries and veins in mammals. (2mks)
9. a) List down three respiratory diseases in human beings (3mks)
b) State the three theories that explain the mechanisms of opening and closing the stomata (3mks)
10. Name the nitrogenous wastes excreted by a fresh water fish (1mk)
11. State the function of septum in t h e heart (1mk)
12. The equation below represents a metabolic process that occurs in the mammalian liver.
Amino Acids → Organic compound + Urea
(a) Name the process (1mk)
(b) What is the importance of the process to the mammal? (2mks)
13. Below is a diagram of an organism

i) State the class which the organism belongs to (1mk)

ii) State two observable characteristics used to classify the organism in the class you have mentioned in
(i) above (2mks)
b) Name two classes of phylum arthropoda with cephalothorax. (2mks)
14. In mitosis in animals chromatids failed to separate and move to opposite poles
a) Name the organelle that the cell was lacking (1mk)
b) Name two regions in plants where cells actively undergo mitosis (2mks
15. a) What is the meaning of the following terms (2mks)
i) Autecology
ii) Synecology
b) The number and distribution of stomata on three different leaves are shown in the table below.
Leaf Number of stomata
Upper epidermis Lower epidermis
ABC 450 0
185 270
03 15

Suggest the possible habitats of the plants from which the leaves were obtained (3mks)
c) Apart from predation, state two other biotic factors that will influence the distribution of an
organism in an ecosystem. (2mks)
16. What is the function of the following structures in the human reproductive organs?
a) Prostate gland (1mk)
b) Uterus (1mk)
c) Epididymis (1mk)
17. Define the term oxygen debt as used in biology (1mks)
18. a) Differentiate between incomplete and complete metamorphosis. Give example in each
case. (4mks)
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19. State two adaptations of a seed to its functions. (2mk)
20. Name the causative agent of cholera (1mk)
21. Define the term resolution power as used in microscopy (1mk)
22. What is haemolysis (1mk)
23. a) Name the compound that stores energy released during oxidation of glucose, (1mk)
b) A goat weighing 15.2kg requires 216KJ while a rat weighing 50g requires 2736KJ per day.
Explain.
24. Explain why plants do not require complex excretory organs. (3mks)
25. Name the instrument used in measuring wind velocity (1mk)
26. What is ecdysis (1mk)

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 MANGU
BIOLOGY
PAPER 2
TIME: 2 HOURS
1. A form one class set up the following experiment. After an hour, the contents of the visking tubing
and the beaker were tested using iodine solution and benedict’s solution.

Record in the table below the expected observations after the contents in set up A and B were tested
using iodine solution and benedict’s solution. [8 marks]

Visking tubing Beaker

Set up Iodine solution Benedicts solution Iodine solution Benedict’s solution

A
B
2. The diagram below shows the association between the alveolus and a blood capillary. Study it and
answer the questions that follow.

8. State the physiological process by which the gas labeled X enters the cell labeled K. (1mk)
9. Identify gases represented by letter X and Y X (1mk)
10. Give two adaptations of cell K to its functions. (2mks)
11. State three characteristics of respiratory surfaces. (3mks)
a) Define the following terms as used in animal nutrition
i) Dentition (1mk
ii) Homodont and heterodont teeth (2mks)
b) State two functions of ileum (2mks)
(c) Explain the importance of the following in the process of photosynthesis; (2mks)
(i) Chlorophyll
(ii) Light

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(d) State one use of Potassium in (K+) ion the bodyThe diagram below shows a cross section through the
female part of a flower.

a) Name the structures labelled W,X, and Y. (3mks)

b) State two functions of the pollen tube. (2mks)
c) What happens to antipodal cells after fertilization. (1mk)
d) Name the structure labelled K and state their role. (2mks)
4. The figure below represents a transverse section of a young stem.

A
E
D B

C
a) Name the parts labelled A and B on the diagram. (2mks)
b) State the functions of the parts labelled C, D and E. (3mk)
c) List three differences between the section shown above and one that would be obtained from the root
of the same plant. (3mks)
SECTION B( 40 MARKS)
Answer questions 6 ( compulsory)and either questions 7 or 8 in the spaces provided questions 8

Times in minutes 3 3
Glucose level in blood in mg /100cm lucose level in blood in mg /100cm
Y Z
0 85 78

20 105 110
30 105 110
45 130 170
60 100 195
80 93 190
100 90 140
120 90 130
140 88 120

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5. The glucose level in mg per 100cm3 of blood was determined in two person Y and Z. Both
had stayed for six hours without taking food. They were fed on equal amount of glucose at the
start of the experiment .The amount of glucose in their blood was determined at intervals .The
results are shown in the table below.
a) On the grid provided, plot graphs of glucose levels in blood against time on the same axes. (7mks)
b) th
What was the concentration of glucose in the blood of Y and Z at the 50 minute? (2mks)
c) Account for the level of glucose in person Y
i) During the first 45 minutes. (2mks)
ii) After 45th minute to the end of the experiment. (4mks)
d) Account for the decrease in glucose level person Z after 60 minutes. (2mks)
e) Low blood sugar level in harmful to the body .ExplaiN (3mks)
7 a) State the various causes of seed dormancy .
b) Describe various factors that affect the process of seed germination.
8. Discuss the adaptations of the mammalian skin to its functions. (20mks)

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 MANGU
BIOLOGY
PAPER 1
MARKING SCHEME
1. a) 1mm = 1000μm
22
area = πr2 = × (2000)2
7
22
= × 2000 × 2000
7
= 125714.29μm2
125714.29μm2
b) = 25142.858μm2
5
2.
osmosis Active transport
(i)does not require energy (i)Require/use energy
(ii)Carrier molecules are involved (ii)No carrier molecules
(iii)Involve movement of solvent molecules (iii)involve movement of solute particles
(iv)Solvent molecules move along a (iv)The solute molecules move against a
concentration gradient concentration gradient
3.
• Thin epithelium i.e. one cell thin
• Highly vascularized to maintain a steep diffusion gradient
• Ileum has villi that are highly folded while lungs have alveoli to increase surface area for
absorption
4.
• Villus
• Increase the surface area for absorption of the digested food substance
• Epithelium
• Lacteal
• Arteriole
• Succus entericus/intestinal juice
• Peptidase, sucrose, polypeptidase, maltase, lipase
5. a) Adenosine Triphosphate
b) P – oxygen
W – carbon (iv) oxide
c) Stroma
d) Condensation
6. a) i) It initiates the clothing process neutralizing an anti – clockwise factor called heparin and
activates prothrombin to thrombin
ii) It activates conversion of fibrinogen to fibrin whish forms a meshwork of fibres on the cut
surface (to trap red blood cells forming a clot)
b) i) One can receive blood only from blood group O
ii) One can receive blood from all blood groups
7. a)
i) Narrow lumen – to enhance capillarity
ii) Lack of cross walls to allow continuous movement of water uninterrupted/continuous
column/stream of water
b) Presence of sieve plates (between the sieve tubes)/perforated walls
Presence of cytoplasmic strands (within the sieve tube lumen)
Presence of companion cells
8.
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 Arteries Veins
Transport blood from the heart to the body tissue Transport blood from body tissue to the heart
Transport oxygenated blood except pulmonary Transport deoxygenated blood except pulmonary
artery vein
9. a) Asthma, tuberculosis, whooping cough
b) Photosynthetic theory
Starch sugar interconversion theory
Potassium ion theory
10. a) Adenosine triphosphate; reject ATP
b) a goat has a small surface area to volume ratio. Its body is less exposed to the environment
hence it losses less heat and requires less energy to replace
11.
• Waste products are mainly from carbohydrates thus are less harmful than proteinous
• Waste products are formed slowly as plants are less active
• Some waste products are reused e.g. oxygen, carbon (iv) oxide
• Some waste products are removed by diffusion
• Some waste products are stored in insoluble form in dead tissues/leaves/fruits/seeds
12. a) Deamination
b) Removal of excess amino acids
Availing energy in the body
Formation of glycogen/fat for storage
13. i) Class Pisces
ii) presence of fins for locomotion
Body covered by scales
iii) Crustacea
Arachnida
14. a) Centriole
b) Root tips
Shoot tips
Cambium
15. a) i) Study of a single species within a community/ecosystem/habitat/environment
ii)Study of natural communities/different species within an ecosystem
b)
Leaf Habitat
A Aquatic/fresh water
B Forest terrestrial
C Arid/semi – arid/desert
16. a) Secretes alkaline fluid which neutralizes the vaginal fluids and activates sperms
b) Uterus
Site of attachment and growth of embryo
Its muscular contractions aids in expulsion of fully developed foetus during birth
c) Epididymis
Storage of sperms temporarily
Site for maturation of sperms
17. Amount of oxygen required to get rid of lactic acid that has accumulated in the muscles/tissues
when the supply of oxygen is lower than the demand
18. a) Complete metamorphosis undergoes 4 steps i.e.
Egg → larva → pupa → adult while incomplete metamorphosis
undergoes three stages i.e. egg → nymph → adult
19. Has seed coat to protect embryo
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 Has food stores/reserves to provide nourishment to embryo
Low water content to reduce chemical reactions during dormancy
20. Vibrio cholera
21. Ability of the microscope to separate closely packed particles to appear separate
22. A process/phenomenon where red blood cells burst when placed in hypotonic solution
23. Ammonia
24. Separate the heart into two halves hence preventing the mixing of oxygenated blood and
deoxygenated blood
25. Anemometer
26. Shedding off of the exoskeleton in arthropods

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 MANGU
BIOLOGY
PAPER 2
MARKING SCHEME
1.
Visking tubing Beaker
Set Iodine solution Benedict’s solution Iodine solution Benedict’s solution
up
A Iodine solution Benedict’s solution turns green, Iodine solution Benedict’s solution turns green,
turns blue black yellow, brown and finally remains brown yellow, brown and finally
orange orange
B Iodine solution Benedict’s solution turns green, Iodine solution Benedict’s solution turns green
remains brown yellow, brown and finally turns blue black and finally yellow
orange
2. a) Diffusion
b) X – oxygen Y – carbon(iv)oxide
c) Lack nucleus to pack a lot of haemoglobin
Biconcave shaped to increase surface area for gaseous exchange
Able to change their shapes to squeeze through narrow capillaries
Are many to increase the oxygen carrying capacity
d) Moist for respiratory gases to dissolve
Large surface area for gaseous exchange
Highly vascularized for rapid transportation of respiratory gases
Thin walled for respiratory gases to diffuse over short distance
3. a) i) Description of type, arrangement and specialization of teeth
ii)
Homodont Heterodont
Same size, shape and function Different size, shape and function
b) Site for digestion
Site for absorption
c) i) Traps/absorbs sunlight for photosynthesis
ii)Splits water molecules to hydrogen and oxygen gas
d) Transmission of nerve impulse
4. a) X – polar nuclei Y – Ovum (egg cell) Z – integuments
b) Dissolves the tissue of the stroma, style and ovary
Forms pathway for the male nuclei to reach the embryo sac
c) They disintegrate
d) Male nuclei
One fertilizes the egg cell and the other fertilizes the polar nuclei
5. a) A – Epidermis B – Pith
b) C – Phloem – transports manufactured food from the leaves to the rest of the plant
D – cambium – they divide to form new cells that are added to older ones bringing about
secondary growth
E – Xylem – transports water and dissolved mineral salts from the leaves to other parts of the
plant
c)
Section of the stem Section of the root
1.Lacks root hairs 1.Has root hairs
2.Has a pith 2.Lack a pith
3.vasular bundles arranged radially 3.The xylem is star shaped with the phloem in between
4.Has a cambium ring the arms/extensions of the xylem
4.Lack a cambium ring
6. a)
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 b) Y – 120mg/100cm3
Z – 178mg/100cm3
c) i) Blood sugar level increased to 130mg/100cm3; glucose is being absorbed from the intestines; some
of it by passes the liner without entering the cells thus raising blood glucose level
(ii)Glucose concentration decline declined to normal 90mg/100cm3 high blood glucose stimulates the
pancreas to produce insulin; which stimulates the liver cells to take up glucose; and consists it to
glycogen;
e) Some of the glucose is used in respiration to generate energy; some is lost in urine
7. a)
Embryo may not be fully developed/ immature embryo
Presence of chemical inhibitors (that inhibit germination in seeds e.g. abscisic acid)
Very low concentration of hormones e.g. gibberellins and enzymes reduces the ability of seeds to
germinate
Hard and impermeable seed coat prevent entry of air and water in some seeds e.g. (wattle)
In some seeds the absence of certain wavelengths of light; make them remain dormant
Freezing of seeds during winter lowers their enzymatic activity rendering them dormant
b) i) water:
Activates the enzymes and provides the medium for enzymes to act and break down the stored food
into soluble form
Water hydrolyses and dissolves the food materials
Is the medium of transport of dissolved food substances through the various cells to the growing
region of the radical and plumule
Softens the seed coat to facilitate emergence of the radical/plumule
ii) Oxygen – necessary for respiration to provide energy needed by germinating seeds in division and
growth
iii) Temperature
Seeds will not germinate at 0℃ or above 47℃. The optimum temperature for seed germination is
30℃
High temperature kill the protoplasm/destroy protoplasm/denature enzyme
At very low temperatures, the enzymes are inactive
Rate of germination increase with temperature until it reaches an optimum
iv) Enzymes
Facilitates the oxidation of stored food substances to release energy/carbohydrates respiration to
release energy
Hydrolyses carbohydrates to glucose, lipids to fatty acids and glycerol, proteins to amino acids
8. Cornified layer made up of dead cells that prevent entry of bacteria/prevent physical
damage/desiccation
Malpighian layer secretes melanin that protects the body against U.V radiation
Malpighian layer has actively dividing cells that give rise to the granular layer
Sebaceous glands produce sebum/oil substance with antiseptic that kills bacteria and keeps hairs
subtle
Presence of blood vessels (in dermis) which dilate when body temperature is high; to lose heat or
which constrict when the body temperature is low to retain heat
Blood vessels provide nutrients/oxygen to cells of the skin and remove nitrogen wastes and
carbon(iv)oxide which produces sweat which when evaporates from the surface of the skin cools the
body/lowers body temperatures
Presence of sensory cells/nerve endings sensitive to pain/touch/heat/cold which enable the organism
to respond to changes in the environment
Subcutaneous fat/adipose tissue insulate the body against heat loss
Has hair follicle which erect when body temperature is low to trap air which insulates the body
against heat loss/which lie flat when the body temperature is high to trap less air to allow more heat
loss

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 BAKAKE
231/1
PAPER 1
THEORY
TIME: 2 HOURS
1. State two characteristics of organisms that are easily observed in both animals and plants.
(2marks)
2. a) Terrestrial insects such as locusts were captured and their blood was analysed. It was found that
the blood does not have blood pigments such as hemoglobin. Explain. (2 marks)
b) State how the tracheal system in insects is adapted to gaseous exchange. (3 marks)
3. State two functions of a diastema in herbivores. (2 marks)
4. State three biotic factors that could affect an antelope living in Masai Mara. (3 marks
5. Describe how the leaves of submerged plants are adapted to gaseous exchange. (3 marks)
6. Name the part of the seed whose growth brings about epigeal germination. (1 mark)
7. State three aspects of light that affect the rate of photosynthesis. (3 marks)
8. a) Identify the class with organisms that have three body parts and three pairs of legs.
(1 mark)
b) Suggest three reasons why members of the class named in (a) above are adapted to all types of
habitats. (3 marks)
9. a) List three types of gene mutation. (3 marks)
b) i) What are sex-linked genes? (1 mark)
ii) Name two conditions that are sex-linked. (2 marks)
10. a) Name two digestive enzymes produced in their inactive form. (2 marks)
11. Name the organelles that carry out the following functions (4marks)
i) Destroy old and worn-out organelles
ii) Formation of spindle fibres
iii) Osmoregulation
iv) Selective passage of substances into the cell
12. a) Why would you give an athlete glucose and not sucrose after a race? (1mark)
b) What happens to lactic acid after oxygen debt recovery? (2marks)
13. The diagram below represents a plant cell that was subjected to a certain treatment.

At the start At the end of the experiment

a)
Account for the shape of the cell at the end of the experiment. (2 marks)
b)
Draw a diagram to illustrate how an animal cell would appear if subjected to the same
treatment. (1mark)
14. Name two types of valves in the heart. (2 marks)
15. a) Name the hormones that controls metamorphosis in insects (2marks)
b) Give one advantage of metamorphosis in insects (1mark)
16 a) Name the physiological process by which water molecules move from one cell to the other.
(1mark)
b) State the significance of the process in a) above (3marks)

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17. The graph below represents growth pattern in a group organism

a) Name the type of growth curve (1 mark)

b) Name the phylum that shows this type of pattern (1 mark)
c) State one disadvantage of this type of pattern (1mark)
18. a) How would you proof that a species of wildbeest in Tanzania belongs to the same species as a
similar looking wildbeest in Kenya (1 mark)
b) State two principles of Binomial Nomenclature. (2 marks)
19. Explain how altitude may affect the rate of breathing (2marks)
20. The diagram below shows some processes that take place in the ovary and oviduct around the time
of fertilization.

Name
i) The process labeled A (1mark)
ii) Structure X and B (2marks)
iii) The hormone produced by structure labeled X (1mark)
21. a) State three structural differences between arteries and veins (3marks)
b) Name the blood vessels that transports blood to the following; (3marks)
i) heart to the lungs
ii) Small intestine to the liver
iii) Aorta to the kidney
22 a). State two theories that explains origin of life (2marks)
b) State three evidences of organic evolution (3marks)
23. Name the causative agent of the following diseases (2marks)
i) Malaria
ii) Typhoid
24. State three factors that increase the rate of traspiration. (3 marks)
25. Identify three methods that cause fruit dispersal. (3 marks)
26. State one distinguishing characteristic of Kingdom Monera (1mark)

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 BOKAKE
231/2
PAPER 2
THEORY
TIME: 2 HOURS
SECTION A (40 MARKS)
1. The diagram below represents a plant cell organelle;

a) Name the organelle (1mark)

b) In which of the labeled parts does carbon (IV)oxide fixation occur? (1mark)
c) Name the parts labeled A and B and state how each is adapted to its function (4marks)
d) Explain what would have happened to the structure labeled X had the plant been kept in darkness for
48 hours (2marks)
2. A group of students set up an experiment as shown below. The experimental set ups were left for 20
minutes.

The observation after 20 minutes were as shown in the table below;

Set up Observations
Inside tubing Outside tubing
A Blue black colour Colour of iodine
B Colour of iodine Colour of iodine

a) State the process being demonstrated in this experiment. (1mark)

b) Explain the results in set up A; (4marks)
c) Why was there no blue black colour inside the visking tubing in set up B; (2marks)
3. The diagram below represents the nitrogen cycle;

Page | 211
a) Name the process labeled; (2marks)
i) L
ii) N1 and N2
b) Name the organisms that convert M into nitrates. (1mark)
c) Name the organism in plants which promotes process K (1mark)
d) State the relationship between the organisms stated in (c) above and the plant; (1mark)
e) How would excess pesticides in the soil interfere with process K; (2marks)
f) If F1 is nitrogen fixation by free-living bacteria, F2is nitrogen fixation by what? (1mark)
4. The diagram below shows a mould of the genus Rhizopus;

a) Name the kingdom to which it belongs; (1mark)

b) Name the structures labeled A and B. (2marks)
c) Give the functions of the structure labeled B. (2marks)
d) How do the structures labeled B differ from plant roots. (1mark)
e) Give two ways in which members of the kingdom you stated in (a) above are useful to man.
(2marks)
5. (a) Name the two types of variations. (2marks)
(b) In a garden with pea plants, 625 plants had tall stems while 205 had short stems in the F2
generation;
i) Work out the ratio of tall to short plants (give your answer correct to the nearest whole number)
(1mark)
ii) Using letter T to represent the dominant gene, work out a cross between an F1 offspring and a
short plant. (4marks)
iii) What is the genotypic ratio from the cross in b (ii) above (1mark)

SECTION B:
Answer question 6 (compulsory and either question 7 or 8 in the spaces provided after question 8:
6. An experiment was carried out to investigate transpiration and absorption of water in a certain plant
species. The plants were potted and supplied with adequate water. The amount of water lost and
absorbed was determined. The results are shown in the table below;

Time of the day Amount of water in grams

Transpiration Absorption
0700-0900 30 15
0900-1100 40 25
1100-1300 48 34
1300-1500 56 45
1500-1700 40 50
1700-1900 25 40
1900-2100 15 28
2100-2300 10 21

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a) Using the same axes, plot graphs to show transpiration and absorption of water in grams against time
of the day. (7marks)
b) At what time of the day was the amount of water the same for transpiration and absorption;
(1mark)
c) Explain the shape of the graphs of: -
i) Transpiration (3marks)
ii) Absorption (3marks)
d) Suggest what would happen to transpiration and absorption of water if the experiment was continued
for another 2 hours; (2marks)
e) Name two factors and explain how they would affect transpiration and absorption at any given time.
(4marks)
7. (i) Describe the process of fertilization in flowering plant. (10marks)
(ii) How is the human male reproductive system adapted to its functions? (10marks)
8. (i) Explain the methods of excretion in plants. (10marks)
(ii) Explain how the nephron is adapted to its functions. (10marks)

BOKAKE
231/3
PAPER 3
(PRACTICAL)
TIME: 1¾ HRS
CONFIDENTIAL
Each of the students should be provided with;
1.iodine solution
2. Benedict’s solution
3. 1 piece of Visking tubing of 10cm
4. Two piece of thread of 10cm each
5. 30mls of glucose solution labeled L
6. 30mls of starch solution labeled K
7. 4 test tubes
8. Test tube holder
9. two droppers
10. Means of heating

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 BOKAKE JOINT EXAMINATIONS.
231/3
PAPER 3
(PRACTICAL)
1HR 45 MINUTES
1. The photograph below shows the arrangements of different type of cells and tissues in a certain
living organism. Study it and answer the questions that follow.

a) i) From what part of the plant was the photograph obtained. (1 mark)
ii) Name the parts labeled. P,Q,R,S and T (3marks)
b. i) State the function of the part labeled Q. (1mark)
ii) State two adaptations of structure Q to its function. (2 marks)
c. State two environmental factors which regulate the function of the part labeled P. (2 marks)
d. Measure the length of one cell of region labeled Q on the photomicrograph whose magnification is
X5000.What is the actual length of the cell in micrometer? Show your working. (3marks)
2. You are provided with solution labeled L and K.
a) Use the reagents provided to determine their identity. Record your procedure, observation and
conclusion in the table below. (6 marks)
Food substance procedure observation conclusion

b. Tie one end of the visking tubing provided tightly. Put solution K in the visking tubing and tie the
open end. Imerse the visking tubing in the beaker containing solution L. Let the set-up stand for
about 30 minutes.
i) Test the contents in the visking tubing with iodine and benedict’s solution. Record your procedure,
observation and conclusion in the table below. (3marks)
Test with procedure observation conclusion
Iodine solution
Benedict’s solution
ii) Test the contents in the beaker with iodine and Benedict’s solution. Record your procedure,
observation and conclusion in the table below.

Test with procedure observation conclusion

Iodine solution
Benedict’s solution
c. Account for your observation in b(i) and (ii) above. (4marks)
d. What does a visking tubing equite to in a living organism?

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3. Study the organisms drawn below and answer the questions that follow.

(d) Use the dichotomous key below to identify the class the organisms belong to. (12 marks)
c) (a) Phylum Chordata ……………………………………………………… go to 2
(e) Phylum Arthropoda ……………………………………………………. go to 3
d) (a) Has scales on the body ………………………………………………… go to 4
(b) Has no scales on the body …………………………………………..… Mammalia
3. (a) Has cephalothorax ……………………………………………….……. Arachnida
(b) Has no cephalothorax …………………………………………………. go to 5
4. (a) Has fins ………………………………………………………………… Pisces
(b) Has no fins ……………………………………………………………... go to 7
5. (a) Has three pairs of legs …………………………………………………. Insecta
(b) Has more than three pairs of legs ……………………………………… go to 6
6. (a) Two pairs of legs per segment ………………………………………… Diplopoda
(b) One pairs of legs per segment …………………………………………. Chilopoda
7. (a) Has feathers ……………………………………………………………. Aves
(b) Has no feathers ………………………………………………………… go to 8
8. (a) Has a tail ……………………………………………………………….. Reptilia
(b) Has no tail …………………………………………………………….. Amphibia
(b) Name the type of reproduction shown by specimen B and state it disadvantages. (2marks)

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 BOKAKE
PAPER 1
MARKING SCHEME
1. Growth and development
Reproduction
2. a) insects blood does not transport respiratory gases hence does not contain haemoglobin
b) Numerous to increase the surface area for diffusion of gases
Lack Chitin to allow easier diffusion of gases
3. Povide space for tongue to move food within the mouth
Enables the animal to separate newly cut vegetation /food from regurgitated food
4. Competition
Predator-prey relationships
Diseases
Parasitism
5. Leaves lack cuticle for gases to diffuse in and out
Leaves have large air spaces to store air for gaseous exchange
Leaves are thin to reduce the distance for diffusion of gases
6. Hypocotyl
7. Duration
Quality
Intensity
8. Insecta
9. Show internal fertilization to increase chances of survival
Excrete uric acid hence can survive in any environment
Have a chitinous exoskeleton to protects them against water loss.
10. pepsin
Trypsin
Rennin
11. i) Lysosomes
Centrioles
Contractile vacuoles
Cell membrane
12. a) glucose is highly soluble in water /blood hence is faster and easily transported to the
respiratory sites.
Glucose is very simple in structure than sucrose hence easy to oxidize to yield energy to
the body cells.
b) It is oxidized to release energy
13. a) Plant cell was placed in a hypertonic solution to its cell sap hence lost water through
osmosis and became plasmolysed.
b)

14. Atrio-ventricular valves/Cuspid valves

Semi-lunar valves
15. a) Ecdysone-moulting in adult
Juvenile – moulting in larva
b) Adult and larva exploit different niches
Reduce competition for food
Escaping adverse environmental conditions
16. a) osmosis
b) Feeding in insectivorous plants
Opening and closing of stomata

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 Absorption of water from the soil by roots
Osmoregulation
17. a) Intermittent
b) Arthropoda
c) Hardened exoskeleton limits the growth/size of organisms
18. a) If they can interbreed to produce a viable/fertile offspring.
b) The generic name is first written followed by the specific name
The first letter in the generic name must be a capital letter and the rest are small
letters.
The two parts of the name are underlined separately when typed or handwritten.in printed
manuscripts, they should be in italics.
19. Rate of breathing increase with increase in altitude; Oxygen concentration in the air decrease with
increase in altitude.
20.(a) i) Implantation
ii) Ovary produces ova
Oviduct/fallopian tube provides site for fertilization
iii) Oestrogen
21. a) Arteries have no valves except those at the base of the main artery while veins have valves
throughout their length.
Arteries have narrow lumen while veins have wider lumen.
Arteries walls are thick, muscular with more elastic fibres while veins have thin walls, less
muscular with less elastic fibres.
b) i) Heart to the lungs-pulmonary vein
ii) Small intestine to the liver-hepatic portal vein
iii) Aorta to the kidney-renal artery
22. a) special creation theory
Chemical evolution theory
b) Fossil records
Comparative anatomy
Comparative embryology
Geographical distribution of organisms
23. i) Plasmodium ovale; Plasmodium falciparum; Plasmodium vivax
ii) Treponema pallidum
iii) High temperatures
Low humidity
High light intensity
25. Wind dispersal
Water dispersal
Animal dispersal
26. They are Prokaryotic.

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 BOKAKE
BIOLOGY
PAPER 2
MARKING SCHEME
1. a) Chloroplast
b) B
c) A-Grana; contains chlorophyll which traps light energy enabling light reactions of
photosynthesis to take place.
B-Stroma; contains enzymes which control dark reactions of photosynthesis
d) They would be absent because the starch they contain would have been hydrolyzed to
glucose.
2. a) Diffusion
b) Visking tubing is semi-permeable therefore allows passage of iodine molecules from the
beaker into the Visking tubing thus producing a blue black colour with the starch solution.
Starch molecules are too large to pass through the pores of the Visking tubing into the solution
in the beaker hence iodine solution in the beaker does not change colour.
c) Dilute hydrochloric acid hydrolyzes the starch into sugar. The sugar does not react with
iodine solution to form blue-black colour
3. a) i) L- absorption
ii)N1 and N2 − nitrification
b) Nitrobacter bacteria
c) Rhizobium bacteria
d) Symbiosis
e) Kill the bacteria/Rhizobium
Destroy the root nodules
f) Lighting
4. a) Fungi
b) A- Sporangium B- Rhizoids
c) Anchorage; production of enzymes for digestion of food
Materials; Absorption of soluble nutrients
d) They have no vascular tissues/xylem and phloem tissues.
e) Source of antibiotics (e.g. penicillium)
As food (e.g. mushroom)
Manufacture of alcoholic drinks and leavening of bread.
5. a) Continuous variations
Discontinuous variations
b) i)625tall: 205short
605 205
= 3.05 ≅ 3 =1
205 205
3tall:1short
(ii)
Parental phenotypes tall short
Parental genotypes Tt tt

Gametes T t t t

Offspring genotypes Tt Tt tt tt
Offspring phenotypes tall tall short short

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 iii) 1Tt:1tt
6. a) GRAPH
b) 1500-1700 hrs.
c) i)0700-1500hrs; increase in the rate of transpiration due to high light intensity and high t
emperature
1500-2300hrs; decrease in the rate of transpiration due to decreasing light intensity and low
temperature.
ii) 0700-1700hrs; increase in the rate of absorption of water to replace water lost through
transpiration.
1700-2300hrs; decrease in the rate of absorption of water due to decrease in the rate of
transpiration.
d) Both transpiration and absorption decreases.
e) Wind- rate of transpiration is faster when it is windy due to blowing away of layers of water
vapour
Humidity- when humidity is low, the rate of transpiration is faster due to steep water vapour
diffusion gradient
Atmospheric pressure- rate of transpiration is high at low atmospheric pressure
Light- At high light intensity, stomata open increasing the rate of transpiration
Temperature- at high temperature, the rate of evaporation increases hence increasing the ate of
transpiration.
7. a)
Pollen grains lands and sticks to the stigma; absorbs nutrients from the stigma and forms/develops a
pollen tube.
The pollen tube grows down the style, carrying with it the male gametes. (tube nucleus and
generative nucleus); and it gets nutrients from the surrounding tissues.
As the pollen tube germinates, the tube nucleus occupies a position at the tip of the growing pollen
tube while the generative nucleus follows behind the tube nucleus.
As the pollen tube continues to grow downwards, the generative nucleus divides mitotically into two
male gamete nuclei;
The pollen tube grows through the ovary wall, reaches the ovules and enters the embryo sac through
the micropyle;
At this stage, the tip of the pollen tube bursts open and the tube nucleus disintegrates to release two
male nuclei which enter the embryo sac;
One male nucleus/one of the male nuclei fuses with the egg nucleus to form the diploid zygote; the
other male nucleus fuses with the two polar nuclei to form a triploid endosperm nucleus;
Ovules develop into seeds, integuments into seed coat, ovary forms the fruit, zygote develops into an
embryo, endosperm nucleus develops into endosperm, stamen and petals wither and fall off.
(b)
Penis- is made up of spongy tissue and blood vessels which fill with blood causing it to erect to
facilitate copulation.
The testes- are protected by scrotum and are made up of several and highly coiled seminiferous
tubules which provide a large surface area for sperm production. The testes have sertoli cells that
nourish sperms. The testes are located to hang outside the body to provide a cooler environment for
sperm production. The testes also have interstitial cells which produce male hormones called
androgens. The maim androgen is testosterone.
The epididymis; is highly coiled to provide large surface area for storage of sperms;
The seminal vesicle secretes an alkaline fluid which contains nutrients for the spperms
The prostate gland secretes an alkaline fluid to neutralize the vaginal fluids and activate sperms.
Cowper’s gland secretes an alkaline fluid to neutralize the acidity along the urethra caused by Ph.
Variations of urine.
The sperm duct/vas deferens is tubular for passage of sperms.
The urethra is tubular to expel urine and sperms.

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8. a)
Transpiration- excess water is lost in form of vapour through stomata/lenticels;
Diffusion- carbon(IV)oxide (from respiration) and oxygen (from photosynthesis) are eliminated
through diffusion through stomata/lenticels/cuticles.
Deposition/storage in non-toxic form- some wastes (e.g. calcium oxalate, caffeine, nicotine and
quinine) are stored in tissues (e.g. leaves, fruits, flowers, barks) in non-toxic form.
Tissue/organic fall- plants store some of their wastes in flowers, fruits, seeds, old leaves and the bark
and when these organs fall off from the plants, these wastes are eliminated.
Exudation- some wastes (e.g. latex, salts, gum, calcium pectate, resins) are excreted in semi- solid
form.
Guttation- excess water is excreted in form of droplets through hydathodes.
(b)
Afferent arteriole has a wider lumen then efferent arteriole creating high pressure that enables ultra-
filtration to occur in the glomerulus.
The glomeruli(capillaries) have tiny pores to facilitate ultra-filtration.
The proximal and distal convoluted tubules have the following adaptions:
The tubule is long and highly coiled to increase surface area and slow down movement of filtrate
creating more time for efficient reabsorption.
It is one cell thick /has thin epithelium to reduce distance travelled by substances hence faster
reabsorption of materials.
The tubule is well vascularized /well supplied with blood capillaries for transportation of reabsorbed
materials to create steep concentration gradient for efficient transport of reabsorbed materials.
The cells lining the tubules have numerous mitochondria which provide energy for active
transport/reabsorption of materials.
(d)
The loop of Henle has the following adaptions;
It is long to increase the surface area for reabsorption of mineral salts and water.
It has a counter current flow established between the filtrate flow and the large supply of blood in
capillaries to create large/steep diffusion gradient for efficient re-absorption.

Page | 220
 BOKAKE
BIOLOGY
PAPER 3
MARKING SCHEME
1.
a) i) leaf
ii) P-stoma
Q-palisade cell/layer/mesophylls
R-spongy layer/cell/mesophylls
S- vascular bundle/xylem/phloem
T- intercellular/airspaces
U- Upper epidermis
b) i) Site for photosynthesis
ii) Adaption;
Numerous chloroplasts (which contain chlorophyll) for photosynthesis.
Closely packed/vertical arrangement for maximum absorption of light.
Positioned on the upper surface to absorb maximum light
c) Light
Temperature
d) Length= 1cm±0.1
Actual length = length of image/Magnification
=10000/5000=2 micrometers
2.(a)
Food substance procedure observation conclusion
Starch Put solution K in a test tube Blue-black Presence of
Add iodine solution starch
Put solution L in a test tube No colour change/colour of Absence of
Add iodine solution iodine/brown starch
Reducing sugars Put solution K in a test tube and equal No colour change/colour of Absence of
volume of benedict’s solution; heat to Benedict’s solution remains reducing sugars
boil
Put solution L in a test tube Colour changes to Presence of
Add Benedict’s solution green,yellow,orange,brown reducing sugars
Heat to boil
(b)(i)
Test with procedure observation conclusion
Iodine solution Put contents of Visking Blue black Presence of starch
tubing in a test tube
Add iodine solution
Benedict’s solution Put contents of Visking Colour changes from blue to Presence of reducing
tubing in a test tube green,yellow,orange,brown sugars
Add Benedict’s solution
and heat
Iodine solution Put contents of the beaker No colour change/colour of Absence of starch
in a test tube and add iodine/brown
iodine solution
Benedict’s solution Put contents of the beaker Colour changes from blue to Presence of reducing
in a test tube green,yellow,orange then brown sugars
Add Benedict’s solution
then heat
c) Reducing sugar molecules are small in sizes; able to pass through the semi-permeable membrane
into the Visking tubing by diffusion
Starch molecules are too large to pass through the semi-permeable membrane/Visking tube into the
beaker

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d) cell membrane
3. a)
specimen steps Identity
A 1b, 3a Arachnida
B 1a,2a,4a Pisces
C 1b,2b,5b,6b Chilopoda
D 1a,2a,4b,7b,8a Reptilia
E 1a,2a,4b,7a Aves
F 1b,3b,5a Insect
(b) External fertilization
Disadvantage; -low chances of fertilization
Eggs and zygotes are prone to predators

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 NYERI CENTRAL PRE
231/1
BIOLOGY
PAPER 1
TIME: 2 HOURS
1. The diagram below represents a stage in cell division
a) i) Name the stage of cell division illustrated (1mark)
ii) Give a reason for your answer in a(i) above (1mark)

b) In the space below illustrate the next stage of cell division after the one illustrated (2marks)
2. Explain the disadvantages of inbreeding among living organisms (2marks)
3. a) Give two reasons why anaerobic respiration yield less energy than aerobic respiration
(2marks)
b) Explain why fats are not efficient respiratory substrate (2marks)
4. a) Identify the type of placentation shown by the diagram below (1mark)

b) Give one adaptation of a fruit dispersed by water (1mark)

5. Define the terms
i) Epigynous Flower
ii) Staminate Flower
iii) A Hemiphractid Flower
iv) Cross Pollination
6. Why are gills in fish highly vascularized (1mark)
7. Name three sites where gaseous exchange takes place in terrestrial plants. (3marks)
8. Name two methods by which plants eliminate their waste (2marks)
9. (a) What is the basic unit of DNA molecule? (1mark)
(b) Name 2 chemical components of the basic unit named above (2marks)
10. Study the diagram below and answer the questions that follow.
(a) Name the parts labeled A and B (2marks)

b) How are the parts labelled A adapted to their functions (2marks)

11. Name the two types of mutation (2marks)
12. (a) Distinguish between continuous and discontinuous variations (2marks
(b) Give one example of continuous variation in humans (1mark)

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13. A colour blind woman married a man with normal colour vision. Predict the possible phenotypes and
genotypes of their children. (4marks)
14. Explain why plants lack complex excretory organs (3 marks)
15. The diagram below shows human female reproductive system
(a) Name the parts labelled, A,B and E (3 marks)

(b) State the functions of the structures labelled B, C (2 marks)

16. Give two advantages of internal fertilization over external fertilization. (2marks)
17. Red blood cells from a rabbit were placed in a petri dish containing distilled water. the set up was
left for 30 minutes after which observations were made.
(a) Draw a diagram to show how cells would look like at the end of 30 minutes. (1mark)
(b) Name the process that took place. (1mark)
(c) Describe how the process you have named in (b) above occurred. (3marks)
18. Name the hormones involved in blood sugar regulations. (2marks)
19. Pregnancy continuous if the ovary of an expectant mother is removed after four months. Explain
(2marks)
20. How does the following factors affect the rate of diffusion?
(a) Temperature (1mark)
(b) Surface area to volume area (1mark)
21. Describe how turgor pressure builds up. (2marks)
22. Distinguish between magnification and resolution (2marks)
23. Give reasons why only the five-adjustment knob should be used when using high power objective.
(1mark)
24. Explain the role of antidiuretic hormone when there is excess water in human body (3marks)
25. The diagram below represents a stage during germination of a seed

i) Name the type of germination illustrate in the diagram (1mark)

ii) State the role of the part labelled x during germination of the seeded (2marks)
26. State three physiological mechanism of controlling the human body temperature during a cold day.
(3marks)
27. (a) What is seed dormancy (2marks)
(b) Name a growth in seeds (1mark)
28. The diameter of the field view was estimated to be 5mm under a certain magnification .5 cells were
observed along the diameter of the field of view. What was the diameter of one cell in micros (nm)?
(3marks)

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 NYERI CENTRAL PRE
231/2
BIOLOGY
PAPER 2
TIME: 2 ½ HOURS
SECTION A:(40 MARKS)
1. In an experiment to investigate a factor affecting photosynthesis, a potted plant which had been kept
in the dark overnight was treated as shown in the diagram below and exposed to light.
a) Why was the potted plant kept in the dark overnight? (1 mark)
b) Which factor was being investigated in the experiment? (1 mark)
c) i) Which test did the students perform to confirm photosynthesis in the leaves labelled P and Q?
(1 mark)

ii) State the results obtained in the leaves labelled P and Q. (2 marks)
iii) Explain the results obtained in the leaves P and Q. (2 marks)
d) What was the purpose of leaf Q in the experiment? (1 mark)
2. The table below shows variations in the form carbon (IV) oxide is transported in the blood at rest and
during physical exercise.
Carbon (IV) Oxide transport in blood plasma at rest and during exercise.
Form of transport Rest (mol/s) Exercise
Dissolved CO2 0.52 0.97
Bicarbonate ions 12.34 13.68
Carbon (IV) oxide bound to protein 0.26 0.16
Total carbon (IV) Oxide in plasma 13.12 14.81
PH of blood 7.42 7.09

(a) Explain why more carbon (IV) oxide is transported in form of bicarbonate ion. (2 marks)
(b) Account for high total plasma content of carbon (IV) oxide during exercise. (3 marks)
(c) State how ones involvement in the exercises affect blood PH. (2 marks)
(d) Name the protein responsible for the transport of carbon (IV) oxide in the blood. (1 mark)
3. (a) Spider and crab belong to the same phylum.
i) Name the phylum (1 mark)
ii) State three characteristics that make them to be classified in the phylum you stated in (i) above.
(3 marks)
(b) With two classes of phylum Arthropoda have their head fused with the thorax. (2 marks)
(c) Give two distinguishing characteristics between a bat and a bird. (2 marks)

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4. The diagram below represents the nitrogen cycle. Study it and answer the questions that follow.

(a) i) Name the process represented by K. (1 mark)

ii) Identify the organisms responsible for:
Process G……………… (1 mark
Process J…………………………. (1 mark)
iii) Identifying the compound represented by H (1 mark)
(b) Name a method of population estimation in the following:
i) When studying population of fish in a dam. (1 mark)
ii) When studying transition in habits and population through an area. (1 mark)
(c) Define eutrophication. (2 marks)
5. (a) Haemophilia is a disorder caused by a recessive gene. The gene is sex-linked. Peter who is
haemophiliac marries a wife who is a carrier for haemophilia. Carry out a genetic cross in the
space below using suitable symbols to show what percentage of Peter’s son are haemophiliac.
b) Identify two ways in which blood group inheritance in human contradicts with mendel findings and
conclusion in his monohybrid experiments. (2 marks)
c) Distinguish between genotype and phenotype (1 mark)
SECTION B: (40 MARKS)
Answer question 6 (compulsory) and either 7 or 8
6. The table below shows the changes observed in the dry weight (in milligrams) of a barley seedling,
its embryo and endosperm during the first ten days after the onset of germination.
DRY WEIGHT IN MILLIGRAMS
TIME (DAYS) EMBRYO ENDOSPERM WHOLE SEEDLING
0 2 41 45
2 2 39 43
4 7 32 41
6 15 21 38
8 22 11 35
10 35 6 43
(i) Using a suitable scale on the same axis, plot graphs of dry weight of embryo endosperm and whole
seedling against time. (8 marks)
State and account for the changes in dry weight shown by:
(i) Embryo (4 marks)
(ii) Endosperm (4 marks)
(iii) Explain the role of water during germination. (4 marks)
7. (a) Describe the economic importance of Fungi. (10 marks)
(b) Describe adaptive characteristics of schistosoma. (10 marks)
8. (a) Why is a burning charcoal stove in a poorly ventilated room likely to cause death of the
inhabitants? (4 marks)
(b) Describe the adaptations of the mammalian heart to its function. (16 marks)

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 NYERI CENTRAL PRE
BIOLOGY PRACTICAL (confidential)
FORM 4
TIME: 1HR 45 MIN
1. F – starch solution
2. Solution G1- unboiled diastase enzyme
3. G2 – Boiled diastase enzyme
4. Thermometer
5. 250ml beaker labeled warm water bath
6. Benedict’s solution
7. Iodine solution
8. Means of timing
9. 6 test tubes
10. Test tube rack
11. Means of heating
12. Tripod stand

NYERI CENTRAL PRE

231/3
Biology paper 3
(Practical)
1 ¾ HRS
1. The photograph below shows a pair of mammalian organs with their blood supply. One of the organs
has been sectioned longitudinally. Examine them.

a. Identify the pair of organs. (1mark)

b. i) Name the parts labeled M, T P, S (4marks)
ii) Which of the blood vessels P &Qcarries blood with a higher concentration of urea?
Give a reason for your answer. (2marks)
Blood vessel
Reason
c. Name the structure labeled R and state its function. (2marks)
2. Below is a photograph depicting interaction of organisms in a certain ecosystem?

R Q

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a. Write down a possible food chain involving three organisms found in the photograph above.
(1mark)
b. Draw a well labeled pyramid of biomass using the food chain in (a) above. (3marks)
c. What feeding relationships are exhibited by the animals shown in the photographs? (2marks)
d. Give the adaptations of animal R regarding its feeding relationship mentioned in b (ii) above.
(3marks)
e. A number of leaves are represented by leaves A, B, C, D and. Use the dichotomous key made using
leaves A, B, C, D and E below.

1 a. Leaf veins network………………………………………… go to 2

b. Leaf veins parallel…………………………….…………… B (maize)
2 a. Leaf simple………………………………………………… go to 3
b. Leaf compound ………………………………………… …go to 4
3 a. Leaf margin smooth……………………………………….. A (Bougainvillae)
b. Leaf margin serrated…………………………………….. ________________
4 a. Leaf with five leaflets……………………………………. C (Bombax)
b. Leaf with many leaflets…………………………………….E (Acacia)

f. Using the above dichotomous key show the steps and identify at the leaves shown above.
(10marks)
3. You are provided with three unknown solutions labeled F, G1 and G2. G1 is the same as G2 except
that G2 has been boiled. You are also provided with iodine solution, Benedict’s solution, means of
heating 250ml beaker labeled for a warm water bath, thermometer, tripod stand, means of timing,
test-tubes, test tube holder and test tube rack.
a. Place 2ml of solution F in a test tube and add an equal volume of Benedict’s solution.
i. Shake to mix and then heat to boil and write down your observation. (1mark)
ii. What conclusion do you make from your observation in a (i) above? (1mark)
b. Place 2ml of solution F in a test tube. Add 3 drops of iodine solution and shake to mix and write
down your observation. (1mark)
iii. What conclusion do you make from your observation in b(i) above? (1mark)
c. Place 4ml of solution F in a test tube and add 10 drops of solution G1 and mix. Allow the mixtures to
stand in a warm water bath between 35OC – 38OC for 10 minutes. Divide the resulting mixture into
two portions.
i. To one portion in a test tube add 3 drops of iodine solution and shake to mix and write your
observation. (1mark)
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ii. What conclusion can you make from your observation in c (i) above? (1mark)
iii. To the second portion in a test tube add 2ml of Benedict’s solution, shake to mix and heat to boil and
write your observation. (1mark)
iv. What conclusion can you make from your observation in c (iii) above? (1mark)
d. To about 4ml of solution F in a test tube add 10 drops of G2 and mix, allow the mixture to stand in a
warm water bath between 35OC – 38OC for 10minutes. Divide the resulting mixture into two, carry
out iodine test and Benedict’s test as described in (c) above and complete the table below.
(4marks)
Test Observations Conclusion
Iodine test
Benedict’s test

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 NYERI CENTRAL PRE
231/1
BIOLOGY
PAPER 1
TIME: 2 HOURS
MARKING SCHEME
1. a) i) Metaphase T
ii) Homologous chromosomes still associated as bivalents align at the equator of the cell.
- The nuclear membrane has disappeared and chromosomes are free in the cytoplasm.
- Spindle fibers are fully formed.
b)
2. - Reducing fertility.
- Reduce immune function.

- leads to homozygosity, increasing the chances of genetic disorders.

3. a) Utilizes only the first phase (glycolysis which generates just two ATP molecules, aerobic has
complete cellular processes i.e., glycolysis and Kreb’s cycle.
- Only a small function of glucose is converted into ATP while aerobic large amount of glucose
is oxidized to release energy. (glucose partially broken)
- Lack of oxygen for complete oxidation
b) Fats are not soluble and therefore not easily transported to the sites of respiration.
- Fats require more oxygen to oxidize one gram of fat than that of glucose.
4. a) Basal
b) Tough waterproof testa/epicarp e.g., coconut to prevent soaking by water so that the seeds float
easily and are transported far.
- Fibrous mesocarp/spongy enclose large air space making them lighter to float in water.
- Some have an outer covering that absorbs water smell then bursts open to release seeds e.g.,
water lily.
5. i) Ovary above other floral parts.
ii) A male flower.
iii) Has both male and female reproductive organs.
iv) Transfer of pollen grains from a flower of one plant to another but of the same kind.
6. Rich in supply of blood vessels for supply/transport of gases.
7. - Lenticels
- Stomata REJ : pneumatophores
- Cuticle
8. - Transpiration -Tissue/organ fall
- Diffusion -Exudation
- Deposition/storage in storage in no toxic form -Guttation
9. a) nucleotide
b) 5-carbon sugar (deoxyribose sugar)
A phosphate group/molecule
A organic nitrogenous base
10. a) A – Gill filaments
B – Gill rakers
b) - They are moist to dissolve respiratory gases.
- They have a thin membrane to reduce the distance across which gases diffuse.
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 - They are many to increase surface area for gaseous exchange.
- They have many blood capillaries to increase the surface area for diffusion and transport gases.
11. - Chromosomal mutation/aberrations.
- Gene mutation/point mutations.
12. a) Continuous variations have several intermediates within a population, while discontinuous
variation lack intermediates.
b) Skin colour; height, intelligence.
13.

14.
- Some wastes e.g., gases easily diffuse out;
- Waste products are mainly made from carbohydrates and (NB: Must mention some/most) hence are
not as harmful as proteineous materials.
- Waste products are formed slowly/little accumulation of waste/plants are less active.
- Some waste products (such as 02 and are reusable – recycled.
- Some water products are stored in non-toxic forms in leaves, flowers, fruits and old bark.
15. a) A-Ovary
B-Oviduct
E-Vagina
b) B-site for fertilization, conduct ovum to the uterus.
C – site for implementation site for the development of embryo and foetus.
16. - High chances of fertilization.
- Fewer eggs are produced hence minimal wastage of eggs.
17. a)
b) Haemolysis
c) Distilled water is hypotonic; to contents of red blood cells, water enters in red blood cells by
osmosis; until it bursts.
18. Insulin and glucagon hormone.

19. The placenta produces progesterone hormone that maintains pregnancy.

20. a) Increase in temperature increases kinetic energy of molecules hence faster rate of
diffusion.
b) The higher the surface area to volume ratio, the faster the rate of diffusion; while the lower the
surface area to volume ratio, the slower the rate of diffusion.
21. As plant cells gains water by osmosis, their sap vacuole enlarges and exerts outward pressure on the
cell wall. This pressure increases as more water is taken into the vacuoles which push the autoplasm
against the cell wall.
22. Magnification is the ability to enlarge the specimen resolution is the ability to distinguish objects that
are close to appear distinct.

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23. - To avoid breaking the slide.
- To avoid destroying the specimen.
24. Less Antidiuretic hormone is secreted by the pituitary gland; hence kidney tubules become less
permeable to water; causing less reabsorption of water resulting to a lot of dilute urine.
25. i) Epigeal
ii) Protection of the delicate plumule.
Pulls the cotyledons above the ground.
26. - Shivering (to produce heat)
- Constriction of blood capillaries losing less heat.
- Standing upright of hair to trap air which acts as an insulator.
- Reduced activity of the sweat glands to prevent heat loss.
27. a) It is the inability of a seed to germinate even when provided with conditions necessary for
germination.
b) Abscisic acid.
28. 1mm = 1000um
5mm = 5000um
Cell diameter = Diameter of the field view
Number of cells
5000um
5
= 1000u

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 NYERI CENTRAL PRE
231/2
BIOLOGY
PAPER 2
TIME: 2 ½ HOURS
MARKING SCHEME
a) carbon(iv) oxide concentration
b) i) test for starch
ii) P -iodine solution retains its yellow/brown colour
Q-Iodine solution turns blue-black
iii) P – CO2 required for photosynthesis was absorbed by NAOH. photosynthesis did not take place
hence, starch was not formed Leaf had all requirements for photosynthesis hence, starch was
formed
d) control experiment
2.
(a) The reaction occurs in the red blood cells where enzymes carbonic anhydrase speeds up the rate of
conversion of CO2 to weak carbonate ions that diffuse out of red blood cells into plasma. This
lowers the concentration of carbon (iv) oxide in the blood there buy preventing lowering of PH to
acidic condition
(b) Due to high rate of respiration, carbon(iv) oxide is released into blood, to meet high demand for
energy, respiration rate increases released a lot of carbon(iv) oxide into the blood plasma.
(c) Energy is needed during exercise hence high rate of respiration. coz production increases causing a
drop in PH / faster circulation of lactic acid lower PH
(d) Hemoglobin
3
a) i) Arthropoda
ii) Jointed apparatus
Body segmented
Exoskeleton present
b) Class Arachnida
- class Crustacea
4. a)
- feeding/nutrition
- Nitrogen fixing bacteria
- Denitrifying bacteria
- Nitrates
(b) Capture-Recapture
Line transect/belt transect
(c) Environment by nutrients to the vector resulting in excessive growth of algae

5(a)

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(b) Blood group has multiple alleles ABO
Blood group inheritance shows co-dominance AB
(c) Genotype-this is the genetical constitution of an organism
(d) Phenotype this is the outward appearance of an organism
6. (i) Embryo(4mks)
1st to 2nd days the dry weight remains the same; because the enzymes breaking down the food reserve
in the endosperm are being activated;
From the 3rd day up to the end of the dry weight increases; because the products of hydrolysis in the
endosperm are translocated to the embryo, and used in synthesis of new cellular components;
The weight of the embryo is steadily increasing; cells of the embryo undergo mitotic cell division;
and synthesis new protoplasm; hence the increase in weight;
ii) Endosperm(4mks)
1st and 2nd days dry weight decreases gradually; due to the hydrolysis of food reserve in the
endosperm; from the 3rd day, dry weight decreases rapidly until the decreases rapidly untill the 8th
day after which the decrease is slow; due to the further hydrolysis of food reserve, the products are
translocated to the embryo during germination;
- Decrease in weight; stored food is hydrolysis; and transported to growing religions; for respirations
and synthesis of new cellular materials;
(iii) Explain the role of water during germination
a) Hydrolysis of stored food;
b) Activation of enzymes and germination hormones;
c) Medium for chemical reactions;
d) Medium for transport for hydrolyzed nutrients to growing regions
7.
a) Saprophytic fungi help in decomposition of dead plants and animals
- some like aspergillus cause food spoilage and produce aflatoxins which cause cancer
Yeast is used in breaching and bread baking industries.
Some like penicillin are used to make antibiotics dry out fungi destroy timber
Fungi can be used by military to prepare biological warfare.
Some fungi have symbiotic relationship with not of certain forest trees.
Cercaria and rediae in snails) making it difficult to eradicate the parasite and also increase the
chances of transmission and survival
6. The adult worm in blood produces a chemical substance which protects it against the hosts defence
mechanism
7. The male forms a groove/cancel geophonic canal in which it carries the female. This ensures that the
eggs produced by females are fertilized before they are shed into blood vessels.
8. (a) Burning charcoal produces carbon (ii) oxide which accumulates to high levels in a room.
Haemoglobin has a higher affinity for carbon (ii) oxide; they combine to form carbohymoglobin
which does not easily dissociate. This reduces the capacity of hemoglobin to carry oxygen. Thereby
causing suffocation.
(b) Made of cardiac muscles; which is myogenic /contracting and relaxing without nervous stimulation;
its muscle fibren are intercalated ;spreading electrical charge throughout the muscle; it has a
pacemaker (sino atrial node) ;it has bicuspid and tricuspid valves which prevent flow of blood into
the articles when the ventricles contract; has semilunar valves; which prevent the blood in the
arteries from flowing back top the heart: the right ventricle pumps blood to the lungs the left
ventricle pumps blood to the rest of the body
Has septum that separates the deoxygenated and oxygenated blood

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 NYERI CENTRAL PRE
BIOLOGY
PAPER 3
MARKING SCHEME
1. a. Kidneys (rej kidney) (1mk)
b i. M-aorta (1mk)
T- medulla (1mk)
P-Renal artery (1mk)
S-cortex (1mk)
ii. Blood vessel P; (1mk) most urine which enters the kidney via renal artery is removed through
ultrafication as blood flows through the kidney (1 mk)
c. R-ureter
function; Drains urine from the kidney pelvis to the urinary bladder Below is a photograph depicting
interaction of organisms in a certain ecosystem?
2. Write down a possible food chain involving three organisms found in the photograph above.
Grass → Q (gazelle) → R (cheetah)
a) Draw a well labeled pyramid of biomass using the food chain in (a) above. (3mks)

R (cheetah) Secondary consumers

Q (Gazelle) Primary Consumers

Grass Producers

b) What feeding relationships are exhibited by the animals shown in the photographs? (2mks)
Q – Prey
R - Predator
c) Give the adaptations of animal R regarding its feeding relationship mentioned in b (ii) above.
(3mks)
- High speed, leaps on prey, powerful sharp canines for seizing prey, special carnassials teeth on
the upper jaw for crushing bones, has binocular vision giving it ability to accurately judge
distance of prey for a fruitful leaping
d) A number of leaves are represented by leaves A, B, C, D and. Use the dichotomous key made using
leaves A, B, C, D and E below.
e) Using the above dichotomous key show the steps and identify at the leaves shown above.
(10mks)
Leaf Steps Identity
A 1a, 2a, 3a Bougainvillae
B 1b Maize
C 1a, 2b, 4a Bombax
D 1a,2a,3b Hibiscus
E 1a,2b,4b Acacia
3. You are provided with three unknown solutions labeled F, G1 and G2. G1 is the same as G2 except
that G2 has been boiled. You are also provided with iodine solution, Benedict’s solution, means of
heating 250ml beaker labeled for a warm water bath, thermometer, tripod stand, means of timing,
test-tubes, test tube holder and test tube rack.
a. Place 2ml of solution F in a test tube and add an equal volume of Benedict’s solution.
i. Shake to mix and then heat to boil and write down your observation. (1mk)
A blue colour of Benedict’s solution persists
ii. What conclusion do you make from your observation in a (i) above? (1mk)
Reducing sugar absent

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b. Place 2ml of solution F in a test tube. Add 3 drops of iodine solution and shake to mix and write
down your observation. (1mk)
The solution changed from yellow / brown to blue- black.
iii. What conclusion do you make from your observation in b(i) above? (1mk)
Starch present
c. Place 4ml of solution F in a test tube and add 10 drops of solution G1 and mix. Allow the mixtures to
stand in a warm water bath between 35OC – 38OC for 10 minutes. Divide the resulting mixture into
two portions.
i. To one portion in a test tube add 3 drops of iodine solution and shake to mix and write your
observation. (1mk)
The yellow/brown colour of iodine solution persist.
ii. What conclusion can you make from your observation in c (i) above? (1mk)
Starch is absent
iii. To the second portion in a test tube add 2ml of Benedict’s solution, shake to mix and heat to boil and
write your observation. (1mk)
The colour changes from blue, yellow, orange to brown.
iv. What conclusion can you make from your observation in c (iii) above? (1mk)
A reducing sugar is present.
d. To about 4ml of solution F in a test tube add 10 drops of G2 and mix, allow the mixture to stand in a
warm water bath between 35OC – 38OC for 10minutes. Divide the resulting mixture into two, carry
out iodine test and Benedict’s test as described in (c ) above and complete the table below.
(4mks)
Test Observations Conclusion
Iodine test Colour changes from yellow/ brown to blue - black Starch present
Benedict’s test Blue colour of benedict’s solution persists Reducing sugar absent

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 LANJET EVALUATION EXAMINATION
231/1
BIOLOGY
Paper 1
2 Hours
1. The table below shows concentration of some minerals inside the cells of a water plant and in the
surrounding water.
Mineral Sodium Magnesium Calcium
Cell sap 631 202 318
Surrounding water 28 293 47
a) Name the process by which magnesium is taken up by the plant. (1mark)
b) Explain why maize plant take up calcium minerals quicker in well aerated soils than in water logged
soil. (3marks)
2. Give a reason why a mature plant cell does not lose its shape even after losing water. (1mark)
3. i) State the function for co-factors in cell metabolism. (1mark)
ii) Give one example of a metallic co – factor. (1mark)
4. Name the features that increase the surface area of the small intestines. (2marks)
5. a) Name three characteristics that are used to divide the members of phylum Arthropoda into
classes. (3marks)
b) The diagram below represents a certain plant species.

i) State the class to which the plant belongs. (1mrk)

ii) State one observable xerophytic characteristic seen in the diagram above? (1mrk)
6. The chart below represents a simplified nitrogen cycle.

What is represented by X, Y and Z. (3marks)

7. People can die when they inhale gases from aburning charcoal stove in a poorly ventilated room.
What compound is formed in the human body that lead to such deaths? (1mark)

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8. Explain why blood from a donor whose blood group is A cannot be transfused into a recipient whose
blood group is B. (2mrks)
9. In an experiment, a student covered one of the leaves of a potted plant on both upper and lower
surfaces with blue cobalt chloride paper. The plant was exposed outside for 45 minutes.
Observation: The cobalt chloride on the undersurface of the leave changed into pink in the first 20
minutes only as the upper surface remained blue. However, at the end of the experiment, after 45
minutes, the upper surface also turned pink.
i) State the aim of the experiment. (1mark)
ii) Give one significance of the results obtained. (1mark)
10. When transplanting seedlings, it is advisable to remove some leaves. Explain. (1mark)
11. a) Describe the path taken by carbon (IV)oxide released from the tissue of an insect to the
atmosphere. (3marks)
b) Name two structures for gaseous exchange in plants. (2marks)
c) What is the effect of contraction of the diaphragm muscles during breathing in mammals?
(2marks)
12. The chart below shows the number of chromosomes before and after cell division and fertilization in
a mammal.

a). What type of cell division takes place at Z. (1mark)

b) Where in the female body of humans does process Z occur? (1mark)
c) Name the process that leads to addition or loss of one or more chromosomes. (1mark)
13. State three benefits of polyploidy in plants to a farmer. (3marks)
14. The diagram below represents human foetus.

a) Name the part labelled S (1mark)

b) Give the roles of structure P in; (2marks)
i) Nutrition.
ii) Protection.
d) What is the function of the following in the human male reproductive system?. (2marks)
i) Epididymis.
ii) Scrotal sac.

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15. The diagram represents an experimental set up used by students to investigate a certain process.

Flower Q produced seeds, while P did not. Account for the results (3mrks)
16. Name any two branches of microbiology.(2mrks)
17. Which biological tool would a scientist require to collect rats to be used for study? (1mrk)
18. Distinguish between magnification and resolution as used in microscopy. (1mrk)
19. A group of students set up an experiment to investigate a certain physiological process. The set up
was as shown below.

a) Name the physiological process being investigated. (1mrk)

b) Account for the formation and rise in the level of sugar solution at the end of the experiment.
(3mrks)
20. The scientific name of a blackjack is bidens pilosa. Identify two mistakes in the written name.
(2mrks)
21. State two advantages of natural selection to organisms. (2mrks)
22. a) Give two ways in which sexual reproduction is important in the evolution of plants and
animals. (2mrks)
b) Explain why it is only mutations in genes of gametes that influence evolution. (1mrk)
23. Give the role of the following hormones during menstrual cycle. (3mks)
a) Follicle stimulating hormone.
b) Oestrogen.
c) Luteinizing hormone.

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24. The chart below represents the result of successive crosses, staring with red- flowered plants and
white flowed plants and in which both plants are pure breeding.
Parental genotypes: Red flowers x white flowers

First filial generation

Selfed
Second filial generation
3 red flowers: 1 white flower
Phenotypic ratio 3: 1
(a) What were the parental genotypes? Use letter R to represent the gene for red colour and r for white
colour. (1mrk)
(b) i) What was the colour of the flowers in the first filial generation? (1mrk)
ii) Give a reason for your answer in b (i) above. (1mrk)
(c) What is a test- cross?. (1 mark)
25. a) Name two tissues in plants which are thickened with lignin. (2 marks)
b) How is support attained in herbaceous plants? (1 mark)
26.
27. The diagram below shows a stage of a certain type of cell division.

a) Identify the stage and type of the cell division the above cell is undergoing. (2marks)
b) State two importance of the above type of cell division. (2marks)
27. The photograph below shows the effects of certain pollutant in Nairobi dam. Study it carefully and
use to answer the questions that follow.

i) Suggest the main pollutant in the dam (1mark)

ii) What are the possible effects of pollution illustrated in the photograph (2mrks)
iii) Suggest one possible pollution control measure that can be put in place to save aquatic organisms in
the dam. (1mark)
28. In a capture-recapture exercise to estimate population size of dragon flies on a stretch of rivers,
250flies were first caught and marked. Two days later 500 flies were caught in the second capture
and out of this, 50 flies had marks on their bodies. Estimate the population size of the flies. (show
your working) (3mks)

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 LANJET
231/2
BIOLOGY
PAPER 2
TIME: 2 HOURS
SECTION A (40 MARKS)
Answer all the questions in this section.
1. Examine the diagram below carefully and use it to answer the questions that follow.

(a) Name the parts X, Y and Z. (3 marks)

(b) State the main substance which make-up the part labeled W. (1 mark)
(c) Name the process through which mineral salts move into the structure labeled X. (1 mark)
(d) Explain what happens to a red blood cell when placed in distilled water. (3 marks)
2. (a) What is meant by natural selection? (4 marks)
(b) State four sources of evidences that support the theory of organic evolution. (4 marks)
3. The diagram below shows a set up that was used to demonstrate a certain physiological process.

The glucose solution was boiled and oil added on top of it. The glucose solution was then allowed to
cool before adding yeast suspension.
(a) Identify the physiological process that was being investigated using the above set up. (1 mark)
(b) Why was glucose boiled during the experiment? (1 mark)
(c) What was the importance of cooling the glucose before adding the yeast suspension? (1 mark)
(d) What observation would be made in test tube at the end of the experiment? (1 mark)
(e) How would the observation made in (d) above be affected if oil was not added on top of the yeast
suspension during the experiment? (1 mark)
(f) In another investigation, a bird was found to use 10 litres of oxygen to give a respiratory quotient of
0.7 during period of flight. Name the type of food that was being respired by the bird and determine
the amount of carbon (IV) oxide produced during the same flight.
Type of food (1 mark)

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 Volume of carbon (IV) oxide produced. (2 marks)
4. Pure breed of red cows and pure breed of white bulls were crossed to give F1 calves which had a
mixture of red and white coat known as roan. The F1 were selfed.
a) Using letter R to represent gene for red colour and W to represent gene for white colour work out the
phenotypic ratio of F2. (4 marks)
b) Work out the genotypic ratio of a cross between F1 offspring and white bull. (3marks)
c) Comment on the gene(s) controlling the colour of coats in cattle mentioned above. (1mark)
5. You are provided with photographs of animals. Study the photographs and the dichotomous key
below to enable you identify the taxonomic group to which each animal belongs.

KEY
1. a) Jointed legs present ………………………………………………go to 2
b) Jointed legs absent………………………………………………..go to 7
2. a) Three pairs of legs ………………………………………………..go to3
b) More than 3 pairs of legs……………………………….go to5
3. a) Wings present ………………………………………….go to4
b)Wingabsent……………………………………………Anoplura
4. a) One pair of wings………………………………………Diptera
b)Two pairs of wings……………………………………Hymenoptera
5. a) Four pairs of legs ……………………………………Arachnida
b) More than ten pairs of legs …………………………. go to 6
6. a) One pair of legs in each body segment……… …… Chilopoda
b) Two pairs of legs in each body segment ……………… Diplopoda
7. a) Body partially enclosed in a shell…………………… Mollusca
b) Body surface has spiny projection…………………….Echinodermata
a) Using the key, identify the following organisms to their taxonomic groups. In each case, give the
sequence of steps which you followed in identifying them. (4 marks)
Animal Identity Steps followed
A
B
D
E
b) i) Using observable features only, state the class to which the animal labeled A and B on the
photographs above belong (2 marks)
ii) State two observable features on B, that enabled you to arrive at that answer in (b (i)
above. (2marks)

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 SECTION B
Answer question 6 and either question 7or 8
6. Two sets of a pea seeds were germinated, set A was placed in normal daylight conditions in the
laboratory while set B was placed in a dark cupboard. Starting a few days later the shoots lengths
were measured twice daily and their means lengths recorded as shown in the table below.
Time in hours 0 12 24 36 48 60 72 84
Set A length(mm) 12 14 20 23 28 31 47 54
Set B length (mm) 17 23 28 35 48 62 80 94
a. Using suitable scale draw the graphs of the mean lengths in set A and B against time on the grid
provided (8marks)
b. From the graph state the mean shoot length of each of seedling at the 66th hour (2marks)
c. Account for the difference of curve B and A (3marks)
d. Explain what would happen to set up B if it were allowed to continue to grow under conditions of
darkness (4marks)
e. State three external conditions which should be constant for both set ups (3marks)
7. Describe the role of the following parts in human reproduction
i. Testes (4marks)
ii. Ovary (6marks)
iii. Sperm and ovum (6marks)
iv. Uterus wall/endometrium (4marks)
8. Discuss how the mammalian heart is adapted to its functions (20marks)

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 LANJET
BIOLOGY
PAPER 3
CONFIDENTIAL
1. Each candidate should be supplied with the following
• 3 test tubes in test tube rack.
• Iodine solution – supplied with a dropper
• Adequate distilled water
• Benedicts solution– supplied with a dropper
• Means of heating
• 10% Sodium Hydroxide– supplied with a dropper
• 1% Copper (II) Sulphate– supplied with a dropper
• DCPIP– supplied with a dropper
• 12cm3 of solution M in a boiling tube labeled as solution M
Solution M is prepared by mixing starch and egg albumen.

LANJET EVALUATION EXAMINATION

231/3
BIOLOGY
PAPER 3
PRACTICAL
TIME: 1 ¾ HOURS
1. You are provided with a suspension labelled M.
a) Using the reagents provided only, test for the food substances present in the suspension. In the table
below, record the food tested, procedure, observation and conclusions. 12 marks.
Food TEST Procedure Observation Conclusion

b) Name two enzymes that may be required to digest suspension M in the alimentary canal in human.
(2mark)
c) State role of the following in the experiment. (2marks)
i) Sodium hydrogen carbonate
ii) Dilute hydrochloric acid
2. Experimental evidence shows that most mutations results to variations among organisms. The
illustrations I, II, III and IV below show different possible types of chromosome mutations. Study
them keenly.

a) Identify the types of chromosome mutations illustrated. (4 marks)

b) State the effect of the mutation illustrated in III. (1 mark)
c) In most cases, the mutation in II could be lethal. Explain. (2 marks)
d) During which stage of mitosis does the mutation in I above occur? (1 mark)
e) i) Define a mutation (1 mark)
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 ii) Give two possible environmental mutagens. (2marks)
3. The diagrams below represent body parts of some organisms (animals). Study them and answer the
question that follow

a. i) Suggest the type of food eaten by organisms with the parts labeled A, B, C and F (4mks)
ii) With reasons, suggest the likely habitat of the organism from which the parts labeled D and E
were obtained (4mks)
b. i) Suggest the type of evolution that is exemplified by the organisms labeled D, E and F.
Give reason for your answer. (2mks)
ii) Suggest the significance of the above named type of evolution for the organism (1mk)
c. i) Explain briefly the meaning of analogous structures (1mk)
ii) Give one example of analogous structure (1mk)

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 LANJET EVALUATION
231/1
BIOLOGY
Paper 1
MARKING SCHEME
1. The table below shows concentration of some minerals inside the cells of a water plant and in the
surrounding water.
Mineral Sodium Magnesium Calcium
Cell sap 631 202 318
Surrounding water 28 293 47

a) Name the process by which magnesium is taken up by the plant. (1mrk)

Active transport;
b) Explain why maize plant take up calcium minerals quicker in well aerated soils than in water logged
soil.
More oxygen gas is available for respiration; to generate more energy; needed for uptake of calcium
by active transport; (3mrks)
2. Give a reason why a mature plant cell does not lose its shape even after losing water.
Has a cellulose cell wall; (1mrk)
3. i) State the function for co-factors in cell metabolism.
Substances that activate enzymes; (1mrk)
ii) Give one example of a metallic co – factor.
Metallic ions e.g. iron / mg / Zn / Cu /(accept correct iron forms)
Fe 2+, Mg2+, Ca2+, Mn2+, C02+ , Kl, mo2+, (Reject wrong charges). (1mrk)
4. Name the features that increase the surface area of the small intestines. (2mrks)
Presence of villi and microvilli; must mention both to score
Long;
5. a) Name three characteristics that are used to divide the members of phylum Arthropoda into classes.
(3mrks)
Number of body parts;
Number of jointed appendages;
Number of antennae;
c) The diagram below represents a certain plant species.
i) State the class to which the plant belongs. (1mrk)
Coniferales;
ii) State one observable xerophytic characteristic seen in the diagram above?. (1mrk)
Needle like leaves;
6. The chart below represents a simplified nitrogen cycle.
What is represented by X, Y and Z. (3mrks)
X- Denitrifying bacteria/ denitrification;
Y- Animals/ Herbivores; accept primary consumers;
Z- Nitrogen fixing bacteria (in soil) accept Azotobacter;
7. People can die when they inhale gases from a burning charcoal stove in a poorly ventilated room.
What compound is formed in the human body that lead to such deaths? (1mrk)
Carboxyhaemoglobin;
8. Explain why blood from a donor whose blood group is A cannot be transfused into a recipient whose
blood group is B. (2mrks)
The recipient’s blood plasma produces a antibodies which react with the A antigens ; from the donor
resulting in Agglutination;
9. In an experiment, a student covered one of the leaves of a potted plant on both upper and lower
surfaces with blue cobalt chloride paper. The plant was exposed outside for 45 minutes.

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 Observation: The cobalt chloride on the undersurface of the leave changed into pink in the first 20
minutes only as the upper surface remained blue. However at the end of the experiment, after 45
minutes, the upper surface also turned pink.
i) State the aim of the experiment. (1mrk)
To compare the number of stomata in the upper and lower surface/ To show that the lower surface
of the leaf has more stomata than the upper surface;
ii) Give one significance of the results obtained. (1mrk)
It is an adaptation to reduce water loss through transpiration;
10. When transplanting seedlings, it is advisable to remove some leaves. Explain (1mrk)
To reduce the number of stomata/surface area for water loss;
11. a) Describe the path taken by carbon (IV) oxide released from the tissue of an insect to the
atmosphere. (3mrks)
CO2 diffuses into tracheoles; follows the trachea; then through spiracles;
d) Name two structures for gaseous exchange in plants. (2mrks)
Spongy mesophyll cells;
Cuticles;
Lenticels;
e) What is the effect of contraction of the diaphragm muscles during breathing in mammals?.
Muscles of diaphragm contract; causing the diaphragm to flatten (from dome position);The
external intercostals muscles contract internal intercostals muscles relax pulling the ribcage
upward/forward and outward in man;
12. The chart below shows the number of chromosomes before and after cell division and fertilization in
a mammal.
a). What type of cell division takes place at Z. (1mrk)
Meiosis;
b) Where in the female body of humans does process Z occur?. (1mrk)
Ovary;
c) Name the process that leads to addition or loss of one or more chromosomes. (1mrk)
Non- disjunction;
13. State three benefits of polyploidy in plants to a farmer. (3mrks)
Resistance to diseases;
Draught resistance;
Early maturity;
Prolonged period of productivity;
Long shelf life;
14. The diagram below represents human foetus.
a) Name the part labelled S (1mrk)
Chorion;
b) Give the roles of structure P in; (2mrks)
i) Nutrition.
Allows passage of nutrients from the mother to the foetus;
ii) Protection
It is a physical barrier preventing mixing of maternal and foetal blood;
Selectively allows some substances to pass through and not others;
What is the function of the following in the human male reproductive system?. (2mrks)
i) Epididymis.
Storage of sperms;
ii) Scrotal sac.
Hold/protect the testis;
15. The diagram represents an experimental set up used by students to investigate a certain process.
Flower Q produced seeds, while P did not. Account for the results (3mrks)
The flower is self-sterile/do not self pollinate;

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 Covering prevents pollination in flower P;
Flower Q received pollen grains from other plants/cross pollination;
16. Name any two branches of microbiology. (2mrks)
Bacteriology;
Mycology;
Parasitology;
17. Which biological tool would a scientist require to collect rats to be used for study? (1mrk)
Bait trap;
18. Distinguish between magnification and resolution as used in microscopy. (1mrk)
Magnification is the number of times the image of an object has been enlarged while resolution is
the ability of a microscope to distinguish between two objects that are very close to each other as
distinct and separate entities;
19.
a) Osmosis;
b) Sugar solution is hypertonic to the cell sap of the potato tissue;water molecules move through the
potato into the sugar solution by osmosis; dissolves the sugar thus increasing the level of sugar
solution;
20. The scientific name of a blackjack is bidens pilosa. Identify two mistakes in the written name.
bidens starts in a small letter instead of a capital letter;
The two names have been underlined as one word but it should have been underlined separately;
21. Causes the elimination of disadvantageous characteristics/perpetuates advantageous
characteristics;
Allow better adapted organisms to survive adverse changes in the environment/less adapted
organisms are eliminated;
22. a) Give two ways in which sexual reproduction is important in the evolution of plants and animals.
(2mrks)
brings about useful variations/desirable characteristics;
Variations make offspring better adapted for survival/more resistant to diseases;
May lead to origin of new species/ leads to speciation;
b) Explain why it is only mutations in genes of gametes that influence evolution (1mrk)
gametes form the new offspring;
23. Give the role of the following hormones during menstrual cycle. (3mks)
d) Follicle stimulating hormone.
It causes Graafian follicles to develop in the ovary
It stimulates the tissues of the ovary to secrete another hormone called oestrogen.
e) Oestrogen.
Brings about repair and healing of the endometrium which is destroyed during menstruation.
f) Luteinizing hormone.
Stimulates the maturity of Graafian follicle.
24. The chart below represents the result of successive crosses, staring with red- flowered
plants and white flowed plants and in which both plants are pure breeding.
(a) RR, rr;
(b) i) Red;
ii) Complete dominance/ gene for red colour is dominant over the gene for white colour;
(c) A cross between an individual of unknown genotype with that of homozygous recessive;
25. a) Schlerenchyma tissue;
Xylem vessels/ xylem tracheids;
b) Turgidity of cells;
26 a). Stage – metaphase rej. metaphase I
Cell division – mitosis
b) State two importance of the above type of cell division. (2mks)
• Forms the basis for asexual reproduction.

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• Formation of new body cells hence growth.
27.
i) Suggest the main pollutant in the dam (1mark)
Domestic effluents;
ii) What are the possible effects of pollution illustrated in the photograph (2mrks)
Reduction of light penetration into the water thus affecting the primary productivity
which brings about the death of autotrophs;
Decomposers deplete oxygen from water, causing death of aquatic organisms;
iii) Suggest one possible pollution control measure that can be put in place to save aquatic organisms in
the dam. (1mark)
28.
First number marked × Second capture
Total population =
Marked recapture
250 × 500
=
50
= 2500 dragon flies < rej. 2500 alone >

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 LANET JOINT EXAMINATION
BIOLOGY
MARKING SCHEME
PAPER 2
SECTION A (40 MARKS) Answer all the questions in this section.
1. Examine the diagram below carefully and use it to answer the questions that follow.
(a) Name the parts X, Y and Z. (3 marks)
X: Sap vacuole;
Y: Tonoplast;
Z: Chloroplast;
(b) State the main substance which make-up the part labeled W. (1 mark)
Cellulose;
(c) Name the process through which mineral salts move into the structure labeled X. (1 mark)
Active transport; /Diffusion;
(d) Explain what happens to a red blood cell when placed in distilled water. (3 marks)
The cell sap is hypertonic to the distilled water; Water molecules move into the cell by osmosis;
making the cell to swell and eventually burst;
2. (a) What is meant by natural selection? (4 marks)
Organisms with suitable variations in a population survives in a competition for resources; those
with unsuitable variations die out; Through the process suitable genes are passed on to offspring’s;
while unsuitable genes are eliminated from the population;
(b) State four sources of evidences that support the theory of organic evolution. (4 marks)
Fossil records/ Paleontology;
Comparative anatomy;
Comparative embryology;
Geographical distribution;
Cell biology;
Serology;
3. The diagram below shows a set up that was used to demonstrate a certain physiological process.
The glucose solution was boiled and oil added on top of it. The glucose solution was then allowed to
cool before adding yeast suspension.
(a) Identify the physiological process that was being investigated using the above set up.(1 mark)
Fermentation / Alcoholic fermentation / Anaerobic respiration;
(b) Why was glucose boiled during the experiment? (1 mark)
Drive off dissolved oxygen/air; from the glucose solution.
(c) What was the importance of cooling the glucose before adding the yeast suspension?(1 mark)
To avoid denaturing the enzymes in yeast cell / destroy zymase enzymes;
(d) What observation would be made in test tube at the end of the experiment? (1 mark)
Calcium hydroxide forms a white precipitate;
(e) How would the observation made in (d) above be affected if oil was not added on top of the yeast
suspension during the experiment? (1 mark)
Calcium hydroxide remains colourless;
(f) In another investigation, a bird was found to use 10 litres of oxygen to give a respiratory quotient of
0.7 during period of flight. Name the type of food that was being respired by the bird and determine
the amount of carbon (IV) oxide produced during the same flight.
Type of food :- Lipid / fat or Oil; (1 mark)
Volume of carbon (IV) oxide produced. (2 marks)
R.Q = Volumeof CO2 produced; 0.7 = CO2 = 7 litres;
Volume of O2 used 10
4. Pure breed of red cows and pure breed of white bulls were crossed to give F1 calves which had a
mixture of red and white coat known as roan. The F1 were selfed.

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(a) Using letter R to represent gene for red colour and W to represent gene for white colour work out the
phenotypic ratio of F2. (4 marks)
Parental Genotype RW R W;

Gametes W X W ;
R R

Fertilization

F2 genotypes
RR RW RW W W;
Phenotypic ratio 1 Red : 2 Roan : 1 White;
Rej. 1 : 2 : 1 only

(b) Work out the genotypic ratio of a cross between F1 offspring and white bull. (3mks)
Parental genotypes RW W W;

Gametes R W X W W ;

F1 Genotype
RW RW WW WW
Genotype RW : WW
Ratio 1RW : 1WW; Rej. Ratio only.
(c) Comment on the gene(s) controlling the colour of coats in cattle mentioned above. (1mk)
Gene for red colour coat and white colour coat are codominant/ have equal dominance;
acc. Incomplete dominance
5.
a) Using the key, identify the following organisms to their taxonomic groups. In each case, give the
sequence of steps which you followed in identifying them. (4 marks)
Animal Identity Steps followed
A Arachnida
B Hymenoptera
D Chilopoda
E Anoplura

b) i) A - Arachnida;
B - Insecta;
State two observable features on B, that enabled you to arrive at that answer in (b (i) above. (2mks)
i) Has three pairs of legs;
ii) Has three body parts;
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 SECTION B (40 MARKS) Answer question six (6) in the spaces provided (compulsory). Choose
either question 7 or 8 and answer in the space provided after question 8.
8. The heart has atrioventicular valves (cuspidvalves); and semi lunar valves; allowing blood flow in
one direction only and prevent backflow.;
- Valves have non-elastic chordae tendoneae preventing atriventricular valves from turning inside out
into auricles during ventricular systole.;
- Has thick muscular walls which contract to pump and push blood;
- Made up of cardiac muscle which are myogenic i.e contract and relax without getting fatigue
- SAN ; AND AVN; which initiate cardiac muscle impulse stimulating contraction of atriac ventricles
respectively.;
- The heart reserved by vagus and sympathetic nerves which regulate the rate of heart beat depending
on body’s physiological/ requirements.;
- Cardiac muscles served by coronary artery and coronary vein for supply of nutrients and O2 and
removal of wastes respectively;
- Has specialized interconnected cardiac purkinje fibres which spread the wave of excitation
throughout the heart muscles.;
- Has four chambers which hold blood briefly before it is pumped to lungs and rest of body.
- Has a septum wall preventing oxygenated blood on the left side of heart from mixing with
deoxygenated blood on the right side
- Has vena cava and pulmonary vein that transport blood to heart auricles from rest of the body and
lungs respectively;
- The pulmonary artery and aorta transport blood away from heart ventricles to lungs and rest of the
body respectively;
- Entire heart is enclosed by a tough double layered protective sac, the pericardium, preventing it from
overstretching as it pumps.;
- Pencandium secretor pericardial fluid lubricating it to reduce friction.;
- Covered by a spongy fatty layer on pericardium protecting it by absorbing any mechawal shock;
(20 marks)

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 LANJET
BIOLOGY,
PAPER 3
MARKING SCHEME
1.
Food Procedure Observation Conclusion
Starch put two millilitres of Brown colour of iodine starch present;
suspension M into a clean SOLUTION turns blue-black
test tube. Add two drops of
iodine solution and shake
well.
Reducing put two millilitres of The blue colour of Benedict’s Reducing sugars
sugar suspension M into a clean solution remains absent.
test tube. Add of two Rej: no colour change
millilitres Benedict’s
solution, shake well and
heat to boil
Rej If Benedict’s is not in
possessive form
Protein put two millilitres of On adding Copper (II) sulphate proteins present.
suspension M into a clean solution, a blue ring forms on
test tube. Add two the solution. On shaking, the
millilitres of sodium mixture turns purple
hydroxide solution and
shake well.
Slowly add 2 drops of
Copper (II) sulphate
solution and shake well.
Vitamin C put two millilitres of DCPIP The blue colour of DCPIP Vitamin C
solution into a clean test solution persist. absent.
tube. Add solution M
dropwise while shaking.

b) Amylase. Any two correct 2marks.

Maltase.
protease
c) Sodium hydrogen carbonate. To neutralise excess hydrochloric acid. 1mark.
Hydrochloric acid. To hydrolyse complex sugars (non-reducing sugars) to simple sugars (reducing
sugars). 1 mark.
2. a) (4 marks)
Illustration Name of mutation
I Non -disjunction
II Deletion.
III Inversion.
IV Translocation
b) Brings about reversing the gene sequence thus enhancing advantageous or disadvantageous genes
(1 mark)
c) lethal since the offspring may lose genes responsible for the synthesis of some vital proteins
(2 marks)
d) During prophase (1 mark)
e) i) Random and spontaneous change in individual’s genetic makeup. (1 mark)
ii) Very high temperatures.

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 Radiations: alpha, gamma, beta, UV and X-rays
Viruses: papilloma
Heavy metals: mercury. Any two correct answers (2marks)
3. a) (i)
specimen Food reason
A Aquatic matter and Invertebrates Wide shovel shaped beak
B Nectar Long, thin beak
C Nuts Short, thick strong beak
F Flesh Strong sharp curved talons
(4mks)
(ii)
part Habitat Reason
D Aquatic Webbed feet for swimming /
wading
E Land (Tree branches) Long fingers / toes for perching

(4mks)
b) i) Divergent evolution
Reason: similar basic structure and embryonic origin but modified into different forms /
appearances (2mks)
ii) Enable the organisms / animals to utilize different ecological niches, to avoid competition for
food. (1mrk)
c) i) Structures with different embryonic origin but have similar function
ii) Wings of birds and insects. (1mrk)

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 MOKASA EXAMINATIONS
231/1
BIOLOGY
PAPER 1
TIME: 2 HOURS
1. Study the figure below and answer questions that follow:

a) Identify the structures labelled X. (1mk)

b) What is the importance of the structures in a legume? (2mk)
2. Define the following terms (2mks)
a) Ornithology
b) Morphology
3. Explain why plants do not need an elaborate excretory system. (3mk)
4. A form one student trying to estimate the size of onion cells observed thefollowing on the microscope’s
field of view.

(a) Define the term resolving power. (1 mark)

(b) If the student counted 20 cells across the field of view, calculate the sizeof one cell in micrometers.
5. State the economic importance of the following plant excretory products:
a) Caffeine. (1mk)
b) Quinine. (1mk)
c) Papain (1mk)
6. State the role of a pooter (1mk)
7. Explain why it is not advisable to be in a poorly ventilated room with a burning charcoal stove.
8. (a) Name the antigens that determine human blood groups (2marks)
(b) State the adaptation that enables the red blood cells to move in blood capillaries. (1mark)
9. Identify TWO primary mechanisms used by animals to prevent entry of microorganisms in the body
10. State two precautions during collection of specimen for Biology research (2marks)
11. State the role of the following hormones in the life cycle of insects: (2marks)
Ecdysone hormone
Juvenile hormone Define the following terms
a) Evolution (1mk)
b) Adaptive radiation (1mk)

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12. The diagram below represents a growth curve in a certain Phylum.

(a) Name the type of growth curve shown. (1mark)

(b) Name the phylum where members show the type of growth curve illustrated (1mark)
14. (a) Name TWO reproductive hormones secreted by the pituitary gland in women (2marks)
(b) State one function of each of the hormones named in (a) above (2marks)
15. A flower has the following characteristics:
Inconspicuous petals
Long feathery stigma
Small, light pollen grains
(a) What is the likely agent of pollination of the flower? (1mark)
(b) What is the significance of the long feathery stigma on the flower? (1mark)
16. The diagram below represents a transverse section of an ovary from a certain flower

(i) Name the structure labelled W (1mark)

(ii) Name the type of placentation illustrated in this diagram (1mark)
17. State the condition under which insulin hormone is released and indicate its biological function.
(3mks)
18. List any three homeostatic functions of the kidney. (3mk)
19. a) What is the basic unit of a DNA molecule? (1mk)
b) Name two chemical components of the unit named in (a) above. (2mk)
20. When a certain breed of red cows is mated with white bulls, the calves obtain a roan colour.
a) Explain the absence of red and white colours among the calves. (1mk)
b) If the calves were interbred, determine the phenotypes of the F2 generation. Use letter R to represent
the gene for red colour and W for white colour. (4mks)
21. The photographs below represent a type of evolution

a) State the type of evolution shown (1mk)

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b) Explain the name given to the structures represented by the photographs (2mks)
22. Why is the pancreas considered as a dual gland (2marks)
23. Distinguish between the terms homodont and heterodont (1mark)
24. State two adaptations of guard cell to its functions (2marks)
25. List two characteristics of stomata found in xerophytes (2marks)
26. Give a reason why microscope sections require to be:
(i) Thin…………………………………………………… (1mk)
(ii) Kept wet (1mk)
27. (a)Identify the mode of feeding of the animal whose dental formula is given below (1mk)
0 0 3 2
𝑖𝑖 , 𝑐𝑐 , 𝑝𝑝𝑝𝑝 , 𝑚𝑚
2 1 3 2
b) Give two reasons for your answer in (a) above. (2mks)
c) What is the role of carnassial teeth (1mk)
28. The following is diagrammatic representation of protein synthesis
x
+ +
H2 O Amino acid
Amino acid

R Molecule Q
a) Name processes R and molecule Q (2mks)
b) Identify bond labeled X (1mk)
29. Distinguish between taxonomy and taxon (2mks)
30. The illustration shown below is of a common organism

a) Using observable features only, state its class (1mk)

b) Give TWO reasons for your answer in (a) above (2mks)
c) State one economic importance of the organism above (1mk)
d) The organism above is a vector of a disease that causes destruction of red blood cells in human. Give
the scientific name of causal agent to the disease (1mk)
31. State the roles of the following parts of a light microscope (2mks)
a) Fine adjustment knob
b) Condenser

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 MOKASA
PAPER 2
TIME: 2 HOURS
SECTION A. 40 MARKS
1. Marriage between closely related members of the same family is highly discouraged. This not only
un-ethical but also there is greater chances of manifestation of genetically inherited disorders. Two
sickle cell traits cousins married. Work out the probability of having a sick child for the disorder
using a genetic cross. [4marks]
a) Explain the advantage of having sickle cell trait for people living in tropic regions. (2mark)
b) What do you understand by the disorder klinefelter’s syndrome. [1mark]
c) Name any other type of disorder due to non-disjunction (1mark)
2. The apparatus below was set up by a student to find out the changes in gases during germination

(a) After 48 hours the level of water in the U-tube at A and B was as shown. Explain the observation.
(b) Calculate the respiration quotient (RQ) from the equation below: (2mks)
2C51H98O6+145O2 → 102 CO2 + 98H2O+Energy
(c) Identify the substrate being respired in the above equation. (1mk)
(d) (i) Where in a cell does glycolysis take place? (1mk)
(ii) What is oxygen debt. (1mk)
3. The following diagram shows what happened to a cell when place in a certain solution

a) What was the nature of the solution in which the plant cell was placed. (1mrk)
b) Identify the force represented by the arrows labelled A, B and C ( 3mrks)
c) Explain how the force labelled C develops ( 3mrks)
d) State one similarity between diffusion and osmosis (1mrk)

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4. The Photograph shown below was taken from a tree bark. Study it then answer the questions.

(i) Name organism labeled Q. (1mk)

(ii) Name two organisms that make up Q (2mks)
(ii) Suggest the association between the identified organisms in b (i) above. (1mk)
(iii) Explaining the role of each organism identified in (ii) above in the relationship (2mks)
(iv) Identify the two possible Kingdoms represented by organism Q. (2mks)
5. The figure below is a diagram of a potometer used by Muthita boys form 2 student to investigate
certain process in plants.

a) Name the process being investigated? (1mark)

b) State one precautions which should be taken when setting up a potometer. (1 mark)
c) The rate of transpiration was determined under normal conditions in the laboratory. Giving reasons,
explain the differences you would expect if the measurements were repeated under the following
conditions.
i.The shoot is placed close to the heat source (2mks)
ii.Some leaves are removed (2mks)
iii.The shoot is placed in a current of air created by a fan (2mks)

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 SECTION B (40 MARKS)
Answer question 6 (compulsory) and either question 7 or 8
6. The table below shows how the quantities of sweat and urine vary with external temperature.
External temperature in degree Celsius Urine cm3/hr Sweat cm3/hr
0 100 5
5 90 6
10 80 10
15 70 20
20 60 30
25 50 60
30 40 120
35 30 200
40 20 240

a) On the same axis plot graphs of the quantities of urine and sweat produced against the external
temperature. (7mks
b) At what temperature are the amounts of sweat and urine produced equal? (1mk)
c) What happens to the amount of sweat produced as the temperature rises? Explain. (3marks)
d) Account for the observation made on the amount of urine produced as the temperature increases.
e) Most of metabolic reactions in the human body that leads to energy production are enzyme
controlled.
(i) What is an enzyme. (1 mark)
(ii) How do change in temperature affects enzymatic activities. (3marks)
(iii) Other than temperature, name other factors that affects enzymatic activities. (2marks)
7. a) Self-pollination and self-fertilization is disadvantageous in flowering plant. In which ways are
these plants adapted to overcome or to minimize self-pollination and self-fertilization.
b) Describe the role of hormones in female menstrual cycle. (10 marks)
8. a) Explain how the following biotic factors affects distribution of living organism in a particular
habitat.
(i) Competition. (5marks)
(ii) Predation (5 marks)
(iii) Saprophytism. (2 marks)
b) Describe the mechanism of inhalation in Homo sapiens sapiens. (8 marks)

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 MOKASA EXAMINATIONS
231/1
BIOLOGY
PAPER 1
TIME: 2 HOURS
1. Study the figure below and answer questions that follow:
c) Root nodules; (rej nodules;root nodule)
d) Converts atmospheric Nitrogen gas into nitrates; that can be absorbed by plants to manufacture plant
proteins; acc biological nitrogen fixation
2.
a) Scientific study of birds;
b) Scientific study of external structures in organisms;
3.
i) Plants reutilize some of their wastes e.g Oxygen;
ii) Wastes are stored in plant parts in non-toxic forms;
iii) Plants are less active hence produce less metabolic wastes;
iv) Organic molecules are synthesized in accordance with plants’ requirements hence rarely accumulate
to toxic levels; (first 3 correct)
4.
(a) Ability of microscope to distinguish two close objects a separate entities; (owtte)
(b) 1mm = 1000ℳm
4mm = 1000ℳm
20 cells → 4000ℳm
1 cells → 4000
20
= 200ℳm
5. State the economic importance of the following plant excretory products:
a) Mild stimulant;
b) Treatment of malaria;
c) Meat tenderizer;
6. Used for collecting small animals from barks of trees and rock surfaces;
7. Charcoal in limited supply of oxygen produces carbon (II) oxide; which combines with
haemoglobin to form a stable compound carboxyhaemoglobin which does not decompose easily;
reducing the capacity of haemoglobin to transport oxygen leading to suffocation hence death;
8. (a) Antigen A; Antigen B; Rej a and b,D
(b) /Pliable/able to change its shape to squeeze through narrow lumens of capillaries;
9. Skin barriers e.g. the cornified layers, sebaceous glands and sweat glands that produce anti-bacterial
secretions; mucous secretions to remove inhaled microbes; Reflex actions e.g coughing/
sneezing/vomiting to expel the microbes from the body; Lytic enzymes in saliva/tears/nasal
secretions kill bacteria; Gastric secretions with HCl to kill bacteria; Blood clotting; (score the first
two)
10. Collect only the required number of specimen for study; do not destroy natural habitat of the
organisms; return all live specimen to their habitats after study; use protective gear to handle harmful
specimen; do not harm specimen features during study
(first 2 correct)
11. State the role of the following hormones in the life cycle of insects: (2marks)
Ecdysone hormone Stimulates moulting or shedding of adult cuticle;
Juvenile hormone Stimulates maintenance of larval characteristics; ACC. Inhibits
moulting,formation of larva cuticle
12. Define the following terms
a) Study of the gradual change in body form of organisms from simple pre-existing to complex modern
forms over a period of time; (owtte)

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b) Process by which organisms become modified from embryonic/ancestral forms into new forms, to
exploit new environments; (owtte)
13.
(a) Intermittent growth curve;
(b) Arthropoda;
14. (a) Follicle stimulating hormone; Luteinizing hormone; Oxytocin; Prolactin; (any 2)
(b)State one function of each of the hormones named in (a) above
Hormone Function
Follicle Stimulating hormone • Stimulates development of the graafian follicle
• Stimulate the tissues of the ovary wall/follicle to secrete
oestrogen
Luteinizing hormone • Stimulates the maturation of the Graafian follicle
• Causes the conversion of the Graafian follicle into corpus
Luteum
• Stimulates secretion of progesterone by the corpus luteum
Oxytocin • Stimulates the contraction of muscles around the areolar
tissue in the breast to squeeze the milk into the alveolar
space.
Prolactin • Stimulates the mammary gland to produce milk
15.
(a) Wind; Rej wind pollination
(b) To increase the surface area to enable it to trap many pollen grains in the air
16. The diagram below represents a transverse section of an ovary from a certain flower
(i) Ovule; Rej seed
(ii) Axile;
17. Insulin is secreted when sugar level rises above normal; it stimulates liver cells to increase oxidation
of glucose; inhibits break down of glycogen to glucose; increases conversion of glucose to glycogen
for storage; (any 2 roles)
18. Regulation of PH; Ionic balance; osmoregulation; rej excretion
19. a) nucleotide;
b) pentose/deoxyribose/5 carbon sugar; nitrogeneous organic bases; phosphate molecule; (any 2)
20.
a) Codominance; gene for red and gene for white have equal degree of expression; (owtte)
b)

+
Parental Roan Roan
Phenotype; Female Male
Parental RW X RW
Genotype;

Gametes; R W R W

RR RW RW WW
F2 offspring ;
F2 Phenotype; 1 red, 2 roan, 1 white
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21. The photographs below represent a type of evolution
a) Divergent evolution;
b) Homologous structures; structures from similar embryonic origin but modified to perform different
functions as organisms exploit different niches; (owtte)
22. Secretes insulin and glucagon hormones to liver; secretes pancreatic enzymes to duodenum;
23. Homodont refers to teeth of similar sizes and shapes and perform same function; heteredont is teeth
of different sizes and description and perform different functions;
(mark as whole)
24. Has thick inner walls and thin outer walls;for flexibility during opening and closing of stomata; Has
chloroplasts; with chlorophyll to trap light energy for photosynthesis;
Acc beanshaped for flexibility;
25. Few; small; sunken; reversed stomatal rhythm; midday closure ( any 2)
26. Give a reason why microscope sections require to be:
(i) Thin To make them transparent/for light to easily penetrate ;
(ii) Kept wet To make cells turgid; (owtte)
27. a) Herbivorous; rej. herbivore
b) Absence of upper incisors (replaced by horny pad); lower canines replaced by diastema;
c) Slices through flesh; crushes bones; (any 1)
28. The following is diagrammatic representation of protein synthesis
a) R Condensation;
Q Dipeptide;
b) Dipeptide bond;
29. Taxonomy is the study of classification; taxon refers to a specific group/unit where organisms with
specific characteristics are placed;
30.
e) Insecta;
f) Three body parts;three pairs of legs;wings rej exoskeleton (first 2)
g) Transmits human diseases;
Plasmodium falciparum rules apply
31.
a) Raises or lowers body tube for shorts distances to bring image into sharp focus;
b) Concentrates light onto stage to illuminate specimen;

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 MOKASA
BIOLOGY
PAPER 2
TIME: 2HOURS
1.

a) Half of their Rbas are sickle/cresent shaped lowering oxygen carrying capacity;Plasmodium requires
high oxygen hence it does not survive in their body.(Heterozygous advantage) (2marks)
b) Conidition where an individual has an extra sex chromosome (1mark)
c) Down’s syndrome
Turner’s syndrome (1mark)
2. a) Germinating seed respired aerobically;O,was used up and CO2 produced was absorbed
NaOH;A partial vacuum was created hence atmospheric pressure pushed water down at A and level
raised at B
b) Respiratory quotient =CO2 produced
O2 consumed
= 102
145
RQ=0.70
c) Lipids/Fats (1mark)
d) i) Cytoplasm (1mark)
ii) Extra amount of oxygen required to get rid of lactic acid that accumulates on the tissue when
oxygen supply is less than demand (1mark)
3.a) Hypotonic solution (1mark)
b) A.Wall pressure
B.Osmotic pressure
C.Turgor pressure (3marks)
c) As the cell gains more water by osmosis;The sap vacuole enlarges;and excert an outward pressure
against the cell walls (3marks)
d) Molecules moves passively from region of high concentration to region of low concentration
(1mark)
4.i) Lichen (1mark)
ii) Fungi(photosynthetic bacteria)
Algae(Blue-green algae) (2marks)
iii) Symbiosis (1mark)
iv) Fungi-provide surface for attachment and moisture
Algae-carry’s out photosynthesis (2marks)
v) Kingdom fungi
Kingdom protoctista (2marks)
5.a) Transpiration (1mark)
b) Assemble under H 2O
Cut leafy shoot under H2O

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 Apply Vaseline
Leafy shoot forms from her (1mark)
c)i) Transpiration rate increases
Temperature increases internal temperature of leaf increasing
Evaporation in spongy mesophyll cells (2marks)
ii) Transpiration decreases
There is reduction in surface are of transpiration (2marks)
iii) Transpiration increases
Artificial wind blowa moisture on leaf surface increasing deficit (2marks)
SECTION B (40 MARKS)
6.
a) GRAPH
b) Urine production decrease with increase in temperature;more water is lost through sweat raising
osmotic pressure;Pituitary gland releases antidiuretic hormone to increase permeability more H2O is
reabsorbed in the kidney tubule (3marks)
c)i) Organic catalyst which is protein in nature that speeds up or slows down energy production
(1mark)
ii) Low temperature-Inactive enzyme
Increase in temperature activates enzyme to optimum temperature(35-40)0c
Temperature above optimum denatures enzyme (3marks)
iii) Co-factors and Co-enzymes
Enzyme inhibitors
Change in PH (2marks)
7.a)
- Mechanism that hinders self fertilization
- Hermaphrodites and monoecism plants
Plants with both male and female structures on same flower;Brightly colouresd petals;scented and
nectars
- Protandry;Male matures early than female part of the same flower
- Protogyny;Female matures earlier than male part of flower
- Self sterility and incompability;The pollen grains cannot germinate on stigma of the same
flower/plant
- Heterosity;Different arrangement of position of stigma and anther e.g.Stigma above anther
i) Follicle stimulating hormone;
- Stimulate development of graafian
- Stimulate tissues of ovary to secrete estrogen
ii) Oestrogen hormone
- Stimulate healing and repair of endometrium
- High level stimulates secretion of LH
iii) Luteinizing hormone;
- Maturation of graafian follicle
- Stimulate ovulation
- Conversion of remains of –corpus luteum
- Stimulate corpus luteum to secrete progesterone (10marks)
iv)
- Progestereone hormone
- Thickening/proliferation of endometrium
- Sustains pregnancy incase of implantation
- High levels inhibits production of FSH (10marks)

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 KABARAK
231/1
BIOLOGY
Paper 1
TIME - 2 hours
Attempt all the Questions
1. Some form one students wanted to collect the following animals for study in the laboratory. State
the suitable apparatus they should use.
i) Housefly (1 mk)
ii) Scorpion (1 mk)
iii) Ants (1 mk)
2. State two reasons why a snake is classified as a reptile. (2 mks)
3. (a) Explain the role of oxygen in Active transport (1mk)
(b) Name two processes that depend on Active transport in animals (2mks)
4. Explain how sunken stomata lower the rate of transpiration (2mks)
5. State how xylem vessel is adapted to its function (3mks)
6). a) Define the term immunity. (1mk)
b) Distinguish between natural immunity and acquired immunity. (1mk)
c) Identify one immunizable disease in Kenya. (1mk)
7. (a) State two adaptations of the alveolus to its functions. (2mks)
(b) Suggest a reason for asthmatic patient producing a wheezing sound during breathing? (1mk)
c) What is the significance of the cartilage found in the human trachea being incomplete (c- shaped
rings) (1mk)
8. Define the following terms;
(i) Inter specific competition. (1mk)
(ii) Carrying capacity (1mk)
9. Suggest two methods that can be used to determine the type of food eaten by animals. (2mks)
10. (a) State one significance of genetics counseling (1mk)
(b) Part of a strand of DNA molecules was found to have the following sequence
A-T-C-G-G-G-A-T-C-T. What is the sequence?
i) Of the complementary strand? (1mk)
ii) On a m- RNA strand copied (1mk)
11). The paddles of whales and the fins of fish adapt these organisms to aquatic habitats.
a) Name the evolutionary process that may have given rise to these structures. (1mk)
b) What is the name given to such structures? (1mk)
c) Give two examples of vestigial organs in man. (2mks)
12. Name the organelles that carry out the following functions (4mks)
(i) Destroy old and worn-out organelles
(ii) Formation of spindle fibres
(iii) Osmoregulation
(iv) Selective passage of substances into the cell
13. (a) Why would you give an athlete glucose and not sucrose after a race? (1mk)
(b) What happens to lactic acid after oxygen debt recovery? (2mks)
14. State the difference between glycolysis and kreb”s cycle based on the following.
a) where they occur. (1 mk)
b) Amount of energy produced. (1 mk)
c) End product(s) (1 mk )
15. a) Under which of the following magnifications would one see a larger part of the specimen X40
0r X500? Give a reason. (2 mks)
b) State how magnification is worked out in a light microscope. (1 mk)

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16. The illustration below shows a transverse section through a mammalian kidney.

a) Name the structures labelled X and Y.

b) State the process in Q that leads to the formation of glomerular filtrate. (1mk)
c) State one function of sebum (1 mk)
17. State three differences in composition between umbilical artery and umbilical vein. (3 marks)
18. (a) What is meant by the term taxonomy? (1mk)
(b) When are two organisms considered to belong to the same species. (2mks)
19. The diagram below shows part of alimentary canal of a mammal

i) Name the parts labeled A and C (2mks)

ii) State the function of the part labeled B. (1mk)
20). The graph below shows the relationship between body temperatures and external temperatures in a
human being and a snake. Study it and answer questions that follow.

a) What happens to the temperature of each organism as the external temperature increases. (2 mks)
b) Humans are described as homoithermic. State the advantage of this condition. (2mks)
21. State three differences between light stage and dark stage of photosynthesis. (3 mks)
22. Define;
i) Pulmonary circulation (1mk)

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 ii) Systemic circulation (1mk)
23 .The diagram below represents a plant cell that was subjected to a certain treatment.

At the start At the end of the experiment

a) Account for the shape of the cell at the end of the experiment. (2 mks)
b) Draw a diagram to illustrate how an animal cell would appear if subjected to the same treatment.
(1mk)
24. a) Give a reason why each of the following steps are followed when preparing cross sections of a leaf
for examination under a microscope.
i) Cutting thin sections. (2 mk)
ii) Placing the sections in water. (1 mk)
25. Explain why the population of people with sickle cell anaemia is higher in malaria prone areas.
(3mks)
26. The diagram below is of a stage in cell division

With a reason identify the stage. (2 mk)

27. The graph below represents growth pattern in a group organism

(a) Name the type of growth curve (1 mk)

(b) Name the phylum that shows this type of pattern (1 mk)
(c) State one disadvantage of this type of pattern (1 mk)

Page | 268
 KABARAK
BIOLOGY
PAPER 3
CONFIDENTIAL
REQUIREMENTS
Each candidate is required to have the following
Question 1:
You are provided with the following materials:
• Specimen A – ripe banana
• Scalpel
• 50 ml beaker
• Glass rod
• 8cm Visking tubing
• 2 pieces of string
• 20 ml distilled water
• 100ml beaker
• 10 ml iodine solution

KABARAK
231/3
BIOLOGY
(PRACTICAL)
Paper 3
TIME - 1 ¾ hours
1. You are provided with the following materials;
• Specimen A
• Scalpel
• 50ml beaker
• Glass rod
• 8cm visking tubing
• 2 pieces of strings
• 20ml distilled water in a wash bottle
• 100ml beaker
• 10ml Iodine solution
1. You are provided with a specimen labeled A. Make a transverse section of the specimen.
(a) Draw and label the section (3mks)
(b) What type of fruit is specimen A? (1mk)
(c) Slice off about 2cm thick disc from the specimen. Peel it. Place the piece into a beaker and mash it
into a paste using a glass rod. Add 20ml of distilled water and stir. Tie one end of the transparent
tubing provided. Decant the extract into the tubing and tie the other end tightly, ensuring there is no
leakage.
Immerse the tubing with its contents in a 100ml beaker containing Iodine solution for 20 minutes.
(i) Record your observations in the table below (4mks)
Extract inside visking tubing Iodine solution outside the visking
tubing
Before the experiment
After the experiment

(i) Explain the results obtained from c(i) above. (5mks)

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2. Study the photographs below and answer the questions that follow.

(a) With observable reasons identify the class of the specimen in the photograph.
(i) Class (1mk)
(ii) Reasons (2mks)
(b) (i) Name the structures labeled P,Q,R,S (4mks)
(ii) State the function of the parts labeled U,V (2mks)
(c) Study the photographs below depicting plants growing in different habitats.

(i) Identify the habitats in which they are found (2marks)

(ii) State the significance of the following structures found in the specimens shown above (2marks)
R, S
3. Below are photographs showing some observable features of animals

(a) Using the features in the order given below, construct a dichotomous key that can be used to identify
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 the specimens in the photographs. (10mks)
• Presence or absence of backbone
• Presence or absence of wings
• Presence or absence of scales
• Presence or absence of pouch
• Bipedal or quadripedal
(b) Study the photographs below showing blood vessels in man.

(i) Using observable features identify the blood vessels E,F (2mks)
(ii) Using observable features only, give two differences between the two blood vessels (2mks)

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 KABARAK
BIOLOGY
PAPER 1
MARKING SCHEME
1. i) Sweep net
ii) Pair of forceps
iii) Pooter
2. Skin is dry and covered by horny/leathery scales
Fertilization is internal
Are ectothermic/poikilothermic
Use lungs for gaseous exchange
3. a) Oxidize food to produce energy that is required for active transport.
b) Reabsorption of sugar and some salts by the kidney
Absorption of digested food from the alimentary canal
Excretion of waste products from body cells
Transmission of nerve impulse
4. Form pits that accumulate moisture; lowering saturation deficit between the atmosphere and sub
stomatal airspaces reducing transpiration
5. Lignified walls to prevent them from collapsing/offer support
Hollow and tubular for continuous flow of water
Narrow to enhance capillarity
Made of dead cells to reduce water demand
6. a) Ability of the body to identify/recognize foreign antigens and develop mechanisms of
destroying them/ability to resist infection
b) Natural immunity is inborn/inherited/passed from parents while acquired immunity is obtained
in life.
c) Tuberculosis
Poliomyelitis
Diphtheria
Whooping cough
Measles
Hepatitis
Covid-19
7. a) Thin epithelium for reduction of diffusion distance of respiratory gases
Highly vascularized to transport gases/maintain a steep concentration gradient
Moist surface to dissolve respiratory gases so that they diffuse in solution form
b) This is because muscles around bronchioles contracts and so reduce their diameter.
c) To permit the swallowing in the oesophagus
8. a) Competition between individuals of different species (inhabiting the same ecological area)
b) Maximum number of organisms an area can comfortably support without depletion of available
resources.
9. Analyzing animal droppings
Direct observation of the animal while feeding
Dissection and analysis of the gut content
Dentition
10 a) Provides information and advice to enable victim to arrive to an informed decision on their
genetic makeup/disorders.
b) i) T –A – G – C – C – C – T – A – G – A
ii) U–A–G–C–C–C–U–G–U
11. a) Convergent evolution
b) Analogous structures
c) Coccyx, appendix, reduced ear muscles, nictating membrane, reduced body hair

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12. i) Lysosomes
ii) centrioles
iii) Contractile vacuoles
iv) Cell membrane
13. a) Glucose is highly soluble in water/blood hence is faster and easily transported to the respiratory
sites
Glucose is very simple in structure than sucrose hence easy to oxidize to yield energy to the
body cells
b) It is oxidized to release energy
14. a) Krebs cycle occur in the matrix of the mitochondrion while glycolysis occurs in the cell
cytoplasm
b) Glycolysis – less energy/2ATP molecules/210kJ produced
Krebs cycle – more energy produced/38ATP molecules/2880kJ
c) Glycolysis – pyruvate/pyruvic acid
Krebs cycle – energy, water and carbon(iv)oxide
15. a) X40 has lower magnification giving a wider field of view
b) Total magnification = eye piece lens magnification X objective lens magnification
16. a) X – cortex
Y – Medulla
b) Ultrafiltration
c) Moisten the skin/makes the skin supple
Antiseptic/kills pathogens/bacteria
17.
Umbilical vein Umbilical artery
Rich in food nutrients e.g. glucose Less food nutrients
Has more oxygen Has less energy
Has less nitrogenous wastes e.g. urea Has more nitrogenous wastes
Less carbon(iv)oxide More carbon(iv)oxide
18. a) It is the scientific study of classification/grouping of organisms into respective ranks/units
using their characteristics.
b) When they can freely interbreed to give rise to viable/fertile offspring.
19. i) A – duodenum
C – oesophagus/gullet
ii) Temporally storage for faeces/undigested/indigestible materials/absorption of water
20. a) Human – remains constant
Snake – increases
b) Enables them to be active throughout
Enables them to exploit different habitats
21.
Light stage Dark stage
-Occur in the presence of light -Occur anytime
-Occur in grana -Occur in stroma
-Produce hydrogen atoms and oxygen gas -Produce glucose
22. a) Plant cell was placed in hypertonic solution to its cell sap. It lost water by osmosis and became
plasmolysed.
b)

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24. a) i) To reduce layers of cells/ sections preventing overlapping hence better penetration of light
(for illumination)
ii) To avoid drying up which may distort the cells
To maintain turgidity of the cells
25. Their red blood cells carry defective haemoglobin (type S) which carries little or no oxygen;
Plasmodium does not survive in their red blood cells hence survive malaria attack; they reproduce
successfully giving rise to more population.
26. Stage: Prophase 1
Reason: Chromatids cross over each other at the chiasmata
Formation of bivalent
27. a) Intermittent
b) Arthropoda
c) Hardened skeleton limits the growth/size of the organism

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 KABARAK
BIOLOGY
PAPER 3
MARKING SCHEME
1. a)

b) Berry
c) (i)
Extract inside the Visking Iodine solution outside the Visking
tubing tubing
Before the experiment White/cream/pale yellow Brown/yellow
After experiment Blue black Brown/yellow
ii) Iodine molecules in the beaker moved into the Visking tubing by diffusion; reacted with starch to
give the blue black colour.
Colour of the iodine outside the Visking tubing remain n unchanged because starch has large
molecules that cannot diffuse through the semi-permeable membrane of the Visking tubing.
2. a) i) Mammalia
ii) Presence of fur
Presence of external ear
b) i) P - Liver
Q – small intestines
R – stomach
S – pancreas
ii) U- secrete saliva
V- Harbors/ contains bacteria that secrete cellulose enzyme that digests cellulose.
c) i) Y – fresh water
Z – dry/arid/semiarid/desert
ii) R – prick/injure/irritate/harm herbivorous/animals
S – fills with air for buoyancy
3. a)1 (a) Animals without a
Backbone…………………………………………...scorpion
(b) Animals with a backbone ……………………...go to 2
2 (a) Animals with wings……………………………. Eagle
(b) Animals without backbone……………………...go to 3
3 (a) Animals with scales……………………………...Monitor lizard
(b) Animals without scales…………………………. go to 4
4 (a) Pouch present……………………………………Kangaroo
(b) Without a pouch…………………………………go to 5
5 (a) Bipedal…………………………………………...Man
(b) Quadrupedal……………………………………...Gorilla
(b) (i) E – vein F – Artery
(ii)
E F
Wide lumen Narrow lumen
Thin wall Thick wall
Presence of valve Valve absent
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 KIPSIGIS
BIOLOGY
(Theory)
TIME: 2 HOURS
SECTION A
1. State the functions of each of the following organelles. 2 maks
i. Ribosomes
ii. Golgi apparatus:
2. Give reasons for caring out the following procedures when preparing temporary wet mounts of
a plant tissue
3. why would carboxyhaemoglobin lead to death 2mks
4. a) Name one salivary gland in humans 1mk
b) State two functions of saliva 2mks
5. State three characteristics of the class crustacean 3mks
6. State three characteristics that ensure cross-pollination takes place in flowering plants
7. State the importance of negative phototaxis to termite 1mk-
8. Name two tissues in plants that provide mechanical support 2mks
9. State three structural differences between biceps and muscles of the gut 3mks
10. The diagram below shows a specified plant cell……….

a) i) name the cell 1mk

ii) Name the parts labeled Dand E 2mks
b) State the function of the part labeled C 1mk
11. a) What is diffusion 2mks
b) How do the following factors affect the rate of diffusion?
i) Diffusion gradient
ii) Surface area to volume ratio
iii) Temperature
12. (a) State the role of light in the process of photosynthesis 1mk
(b) Name one end product of dark reaction in photosynthesis 1mk
13. (a) The action of ptyalin stops at the stomach. Explain 1mk
(b) State a factor that denatures enzymes 1mk
(c) Name the feactures that increase the surface area of small intestines 1mk
14. The diagram below represents region of a root cap

a) Name two regions above X in ascending order 2mks

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b) State the function of the part labeled X 1mk
15. State three ways in which blood capillaries are structurally adapted to their functions
16. How are lenticels adapted for gaseous exchange 2mks
17. Apart from hearing state another function of the human ear 1mk
18. The diagram below illustrates a response by a certain plant ……………

(a) Name the type of response 1mk

(b) Explain how the response illustrated above occurs 3mks
19. Apart from the lungs name two gaseous exchange surfaces in a frog 2mks
20. State two functions of the muscles found in the alimentary canal of mammals. 2mks
21. Name a disease caused by lack of each of the following in human diet
i) Vitamin D
ii)I odine
22. a) State two factors that affect enzymatic activities 2mks
b) Explain how one of the factors stated in (a) above affects enzymatic activities 1mk
23. State the importance of each of the following in living organisms
a) nutrition 1mk
b) excretion 1m
24. State two ways in which chloroplasts are adapted to their functions
25. State two disadvantages of self-pollination
2mks
26. a) Name two types of muscles in mammals 2mks
b) State the location of each of the following muscles in (a) above 2mks
27. state two advantages of internal fertilization 2mks

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 KIPSIGIS
BIOLOGY
PAPER 2
Section A: (40 marks)
1. Examine the diagram below and use it to answer the questions that follow.

a) Name the parts labeled B,C,D

b) What substance makes up part labeled A? (1 mk)
c) Name the process by which mineral salts move into structure B. (1 mk)
d) Explain what happens when a red blood cell is put in distilled water. (3 mks)
2. The figure below is a pedigree showing the inheritance of colorblindness, a disease transmitted
through a recessive gene located on the X – chromosome.

(a) Using the symbol N for normal gene and n for colourblind gene, write down the genotypes of parents
1 and 2. (2 mks)
(b) Work out the possible genotypes of the children 3, 4 and 5 (4 mks)
(c) The diagrams below illustrate chromosome mutations.

Identify the mutations A,B,C (3 mks)

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3. The diagram below shows structures of the bat wing and human arm

(a) These structures are thought to have same ancestral origin. State one structural similarity and one
adaptational difference the two.
(i) Structural similarity (1 mk)
(ii) Adaptational difference (1 mk)
(b) Give two other examples of structures in nature that show the ytpe of evolution as in (a) above).
(2 mks)
(c) Distinguish between the terms ‘ chemical evolution’ and ‘organic evolution’ ( 2 mks)
(d) What is the study of fossils called? (1 mk)
4. The diagram below represents some hormones, their sources and functions in a mammal

Master gland

(I) (III) (V)

Stimulates testes Stimulates growth of Stimulates development
follicle in ovary of corpus leutium

(II)
(IV) (IV)
Stimulates development of secondary sexual Stimulates development
Stimulates Spermatogenesis characteristics of uterine

Male
Female

(a) Identify the gland described as the master gland? (1 mk)

(b) Name the hormones :- II,III,V,VI (4 mks)
c) Describe the consequences of deficiency of hormone II in man. (2 mks)
d) Other than stimulate development of uterine wall, suggest two other functions of hormone VI
(2mks)
5. Ascaris lumbricoides is an endoparasite.
(a) Name the genus to which it belongs (1mk)
(b) State the habitat of the organism (1mk)
(c) State three ways in which the organism is adapted to living in its habitat (3mks)
(d) Mention three ways of preventing spread of the parasite. (3 mks)

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 SECTION B; (40MARKS)
Answer question 6 (compulsory) and EITHER question 7 or 8 in the spaces provided after question
8.
6. The table below shows how the quantities of sweat and urine vary with external temperature.
External Temp Urine cm3/hr Sweat cm3 / hr
0 100 5
5 90 6
10 80 10
15 70 20
20 60 30
25 50 60
30 40 120
35 30 200

(a) On the same graph, plot the quantities of urine and sweat produced against the external temperature
(7 mks)
(b) At what temperature are the amounts of sweat and urine produced equal (1 mk)
(c) What happens to the amount of sweat produced as the temperature rises. Explain the observation?
(3 mks)
(d) Explain the observation made on the amount of urine produced as the temperature increases
(3mks)
(e) How is the skin adapted for temperature regulation? (6mks)
7. Describe the structural adaptations of the mammalian heart to its function (20mks)
8. Describe how water moves from the soil to the leaves in a tree (20mks)

KIPSIGIS
231/3
BIOLOGY CONFIDENTIAL
Each student to be provided with;
1. One irish potato
2. Three boiling tubes
3. 10mls measuring cylinder
4. Scarpel
5. Ruler
6. 15ml Hydrogen peroxide
7. Means of heating
8. Three labels
9. Test tube holder

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 KIPSIGIS
231/3
BIOLOGY
PAPER 3
PRACTICAL
1 ¾ HOURS
1. You are provided with a specimen labeled K and hydrogen peroxide
a) i) What part of plant is specimen K? (1mk)
ii) Give a reason for your answer in a (i) above (1mk)
b) Cut three equal cubes whose sides are about 1cm from specimen K. place one of the cubes in a
boiling tube labeled A; boil the second cube for about 15 minutes and then place it into a boiling
tube labeled B; Cut the third cube into small pieces and place the pieces in a boiling tube labeled C
To each boiling tube add 5ms of hydrogen peroxide
i) Record your observations in the table below (3mks)
Tube Observations
A
B
C
ii) Account for your observations in tubes B and C (4mks)
c) i) Write a chemical equation for the reaction that occurs in test tube A (1mk)
ii) What is the significance of the reaction to living organisms (1mk)
iii) Name the organ in mammals where the above reaction occurs at the highest rate (1mk)
2. You are provided with photographs A, B and C, use them to answer questions that follow.

a) Identify the parts labeled X,Y and Z. (3mks)

b) What common name is given to structure ref?
i) A and C (1mk)
ii) B and C (1mk)
c) Give a reason for your answer in b (i) and (ii) above. (2mks)
d) State the type of evolution that leads to emergence of structures named in 2 b (i) and (ii) above.
(2mks)
e) Identify two differences between structures A and C. (2mks)
f) i) What is a vestigial structure? (1mk)
ii) Give two examples of vestigial structures in human being (2mks)
3. Study photographs C and D and answer the questions.
PHOTOGRAPH C PHOTOGRAPH D

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a) With a reason state the agent of pollination of each of the flowers. (4mks)
b) Classify the plants in photograph D using the taxonomic units below and reasons for your answer.
(4mks)
c) The diagrams below shows a type of cell division occurring in organisms above. Identify each of the
stages A to D giving reasons for your answer. (4mks)
A B

C D

(d). Giving reason, identify the kingdom to which the cell in stages A and B belongs. (2mks)

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 KIPSIGIS
BIOLOGY
PAPER 1
MARKING SCHEME
1. State the functions of each of the following organelles. (2 marks)
i. Ribosomes
site for synthesis of protein
ii. Golgi apparatus:packaging of synthesized materialseg glycoproteins
2. Give reasons for carring out the following procedures when preparing temporary wet mounts of a
plant tissue
a) Making thin plant sections 1mk
- To allow light to pass through
b) Adding water to the plant section 1mk
- to make cells tugid/prevent drying uphence maintain the shape
c) Placing a cover slip over the plant section 1mk
- exclude air and hold specimen in position or in place
3. why would carboxyhaemoglobin lead to death 2mks
- it’s a very stable compound that deos not dissociates therefore reduces the capacitt of haemoglobin
to transport oxygen to the tissues
4. a)Name one salivary gland in humans 1mk
- sumblingual;parotid;submaxillary
b) state two functions of saliva 2mks
- lubricates food;moisten food;soften food;dissolves food;contain salivary amylase hence digest starch
to maltose;provide alkaline media
5. State three characteristics of the class crustacean 3mks
- fused head and thorax ie cephalothorax
- gaseous exchange is through gills
- five or more pair of limbs
- two pairs of antennae
- a pair of compound eyes
- three pairs of mouth parts (labial pals/maxillae/mandible)
6. State three characteristics that ensure cross-pollination takes place in flowering plants 3mks
- presence of special structures that attracts agents of pollination
- protogyny and protandry
- self sterility or incompatibility
7. State the importance of negative phototaxis to termite 1mk
- enables termites to seek favourable habitat away from light so as to avoid predation and dehydration
8. Name two tissues in plants tha provide mechanical support . 2mks
- collenchyma tissues
- sclerenchyma tissues
- turgid parenchyma tissues
9. State three structural differences between biceps and muscles of the gut
3mks
biceps Gut muscles
striated unstriated
multinucleated uninucleated
Long fibres Short fibres
Cylindrical shaped Spindle shaped
10. The diagram below shows a specified plant cell………..ROOT HAIR
a) i) name the cell 1mk
- root hair
ii) name the parts labeled Dand E 2mks

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 -D cell wall;E cell sap/sap vacuole
b) state the function of the part labeled C 1mk
Controls the functioning of the cell/controls cell activities
11. a) what is diffusion 2mks
-movement of the molecules from region of high concentration to sregion of low concentration
b) how do the following factors affect the rate of diffusion
i) diffusion gradient 1mk
- the higher the diffusion gradient the the higher the rate of diffution
ii) surface area to volume ratio 1mk
- the higher the surface area to volunme ratio the rate of difffusion
iii) temperature 1mk
- incresing temperature increases the energy content in a molecule hence faster rate of diffusion
12. (a) state the role of light in the process of photosynthesis 1mk
- to split water molecules/photolysis
b) name one end product of dark reaction in photosynthesis 1mk
- glucose;amino acid
13. (a) the action of ptyalin stops at the stomach.Explain 1mk
-In the stomach there is acidic mediumdue to precence of HCLand ptyalin only works at slightly
alkaline mediumhence denatured
(b) state a factor that denatures enzymes 1mk
-altering PH and hogh temperature above 40
(c) name the feactures that increase the surface area of small intestines 1mk
-presence of villi and micro villi
14.
a) name two regions above X in ascending order 2mks
- zone of cell division/zone of cell elongation/enlargement
b) state the function of the part labeled X 1mk
- to protect apical meristem
15. State three ways in which blood capillaries are structurally adapted to their functions 3mks
- are numerous forming dense network close to every cell for efficient exchange of substance
- have thin endothelium to provide the least distance for diffusind molecules
- have narrow lumen to maintan high pressuere for ultr-filtration
16. How are lenticels adapted for gaseous exchange 2mks
- has a film of moisture to dissolve gas
- has large intercellular airspaces or cells are loosely packed to allow easier circulation of gases
17. Apart from hearing state another function of the human ear 1mk
- maintain balance and posture of the body
18. The diagram below illustrates a response by a certain plant …………….THIMOTROPISM
a) name the type of response 1mk
-thigmotrophism/haptotrophism
b) Explain how the response illustrated above occurs 3mks
- auxins migrate away from the point of contact ;less auxins causes less elongation leading to less
growth; the side far away from point of contact has higher concentration of auxins leading to more
elongation hence more growth and the stem curves /twines along the supporting structures
19. Apart from the lungsname two gaseous exchange surfaces in a frog 2mks
- skin and gills
20. State two functions of the muscles found in the alimentary canal of mammals. 2mks
- serve as valve for regulation of food movement
- muscles contract and relaxes hence causes churning and pushing food along the gut
- contains secretory cells which secrete mucus and intestinal juices
21. Name a disease caused by lack of each of the following in human diet 2mks
(a) Vitamin D

Page | 284
- rickets
(b) Iodine
- goitre
22. (a) State two factors that affect enzymatic activities 2mks
Temperature;PH value;co-factor;enzyme and co-enzyme;enzyme concentration;substrate
concentration;metabolic inhibitors
(b) explain how one of the facters stated in (a) above affects enzymatic activities 1mk
23. State the importance of each of the following in living organisms
(a) nutrition 1mk
- provides organism with food nutrients
b) excretion 1mk
- seperates and removes waste products to avoid poisoning if left to accumilate
24. State two ways in which chloroplasts are adapted to their fuctions
- contain chlorophyllpigment which traps light energy
- have grana which increases surface area for accommodation of large number of ghlorophyll
molecule
- stroma has enzymes that catalyses the rate of photosynthesis
25. state two disadvantages of self pollination 2mks
- lack of hybrid
- disadvantegioue traits are retained within the species
26. (a) name two types of muscles in mammals 2mks
- cardiac muscle
- visceral/smooth muscle
b) state the location of each of the following muscles in (a) above 2 mks
Cardiac-heart
Visceral/smooth muscle-walls of tubular visceral organs eg blood vessels;the gut;oviduct

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 KIPSIGIS
BIOLOGY
MARKING SCHEME
PAPER 2
1. (a) B—Sap vacuole/cell vacuole/vacuole;
C-Tonoplast;
D - Chloroplast;
b) Cellulose;
c) Active transport.
d) The cell sap is hypertonic to distilled water; hence water molecules move into the ceil by osmosis;
making it swell and eventually burst/get haemolysed; (3mks)
2. a) 1 – XNY;
b)

c) A—-Non-disjunction;
B – Translocation
C- Inversion
3. a) i) Structural similarity
Both show the pentadactly limb structure
ii) Adaptational difference.
Human arm has five digits separated into four fingers and an opposable thump for grasping;
The bat wing has. five digits which are long and spread apart to support a large membranous
wing for flight; (2mks)
Different shapes and sizes of beaks in birds;
b) Different feet structure in birds;
c) Chemical evolution explains the origin of life as having occurred when simple chemical compounds
reacted to form the simplest life forms; organic evolution is the progressive development of complex
organisms from simple pre-existing life forms over a long period of time; (2mks)
d) Palaeontology;
4. a) Pituitary gland;
b) II - Testosterone;
III - Follicle stimulating hormone;
V - Luteinising hormone;
VI- Progesterone;
c) Sterility/lack of spermatogenesis; failure of secondary sexual characteristics;
d) Inhibit production of FSH/inhibit production of LH;
5 a) Ascaris
b) Intestines of humans/Pig Acc. large intestine/duodenum. (1mk)
c) Adaptations:
• Has two hosts to ensure survival;
• Lays numerous eggs to increase chances' of survival;
• Has thick cuticle which protects it against digestive enzymes of the host;
• Eggs have a protective shell to survive harsh environmental conditions
• Has tissues tolerant to low oxygen/can survive under low oxygen concentration
• Produce anti-enzymes to counteract the effect of the host’s enzymes;
• Has a muscular pharynx through which it sucks digested food from the host’s intestine;

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d) Prevention
Proper sewage disposal/ proper use of toilet facilities
Maintain proper personal hygiene/washing hands after visiting the toilet;
Boiling/treating drinking water;
Proper cleaning of vegetables and fruits;
6. (a) Labeling of axis
Scale;
Curves;
Plotting points;
b) 24°C;
c) Sweat production increases with increase in temperature; because high temperatures increase the
evaporation rate, hence more sweat is converted to water vapour ; This uses latent heat of
vapourisation from the body causing cooling;
d) An increase in temperature decreases the amount of urine produced; this is due to increased sweating
which raises the osmotic "pressure of blood a lot of water is re aborsobed into blood in the kidney
tubules resulting in the production of little concentrated urine; (3mks)
hair - When hot, the erector pili muscle relax; the hair lies that on the skin surface; to reduce
insulation and encourage heat loss;
OR - When cold, the erector pili muscles contract; causing hairs to stand; and trap a layer of warm
air which insulated the body; (3mks)
Blood verses - When cold blood vessel; constrict (vasoconstriction); Less blood flows near skin
surface; reducing heat loss by radiation and convection;
OR - When hot, blood vessels dilate (vasodilatation); more blood flows on the skin surface;
increasing heat loss by radiation and convection thus cooling the body; (3mks)
Sweat glands – when hot, sweat is released, it evaporates, taking latent heat of vapourisation from
the body; hence cooling it;
OR - When cold, sweat glands release less sweat; there is less evaporation; and hence less heat loss:
Total (9mks) max 6mks)
7. - It is muscular/has cardiac muscles; which are myogenic (does not need nervous stimulation) to pump
blood;
- it is supplies by vagus and sympathetic nerves; which controls the rate of heart beat; (depending on
body’s physiological requirements)
- It has tricuspid valves and bicuspid valves; (between atrium and ventricles) which prevent back How
of the blood into the right and left ventricles respectively when during systole
Present of valve tendons attached to the walls of ventricles and to the atrium ventricular walls; to
prevent atria-ventricular valves from due to changes m the pressure in the ventricles;
Heart is supplied by coronary artery; which supplies food and oxygen to the cardiac muscle for their
pumping action; the coronary vein; in heart removes metabolic wastes;
The heart is enclosed by the pericardium membrane that secretes a fluid which lubricates it (reducing
friction on the walls as it bumps)
The heat is divided into two by the atria-ventricular septum that prevent mixing of oxygenated blood
and deoxygenated blood.
The left ventricles has a thick muscular wall to pump blood at higher pressure to the distant body
issues
The outer part of the pericardium has a fatty layer which act as a shock absorber ;) keeps the heart in
position.
The Sino Atrial Node (S.A.N) the pacemaker region) which initiate the wave of contraction leading
into contraction and relaxation of muscles the arterial-ventricular node? in the heart spreads out
waves of contraction throughout the heart creating the heart beat

Page | 287
8. Water exists as a thin film in the soil between soil particles the concentration of cell sap is greater
than that of the surrounding solution in the soil; Thus drawing water molecules across the cell wall
and cell membrane into the root hair cells, by osmosis; water drawn into the root hair cell dilutes the
ceil sap/makes it less concentrated than that in the adjacent cell water moves into the cortex cells (of
the root)across the endodermis by active transport; into the xylem vessels of the root); then
conducted up into the xylem (vessels) of the stem into xylem of leaves water is pushed/rises up the
stem by root pressure (in the xylem vessels) water rises by capillarity; cohesion; and adhesion forces
of water moves as a continuous uninterrupted water column in the xylem vessels up the tree to the
leaves;

As water vaporizes from the spongy mesophyll cells their cell sap becomes more concentrated than
that of the adjacent cells; This increases the osmotic pressure of the spongy mesophyll cells; As a
result water flows into the cells from other surrounding cells which in turn takes in water from xylem
vessels within the leaf veins. This creates a pull/suction force/transpiration pulls a stream of water
from xylem vessels in the stem and roots; The transpiration pull maintains a continuous column of
water from the roots into the leaves (transpiration stream);

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 KIPSIGIS
231/3
BIOLOGY
PAPER 3
MARKING SCHEME
1. You are provided with a specimen labeled K and hydrogen peroxide
a) i) What part of plant is specimen K? (1mk)
Tuber
ii) Give a reason for your answer in a (i) above (1mk)
Presence of auxiliary buds/scale leaves
b) Cut three equal cubes whose sides are about 1cm from specimen K. place one of the cubes in a
boiling tube labeled A; boil the second cube for about 15 minutes and then place it into a boiling
tube labeled B; Cut the third cube into small pieces and place the pieces in a boiling tube labeled C
To each boiling tube add 5ms of hydrogen peroxide
i) Record your observations in the table below (3mks)
Tube Observations
A Bubbles formed/effervescence occured
B No effervescence
C A lot of bubbles formed
ii) Account for your observations in tubes B and C (2mks)
B Boiling denatured the enzyme catalase,hence could not breakdown hydrogen peroxide,thus no
oxygen gas is produced
C Cutting increased the surface area ,thus exposing more enzymecatalase to breakdown more
hydrogen peroxide to oxygen gas (2mks)
(c) i) Write a chemical equation for the reaction that occurs in test tube A (1mk)
2 H2O2(l)→2H2O(l) + O2(g)
ii) What is the significance of the reaction to living organisms (1mk)
Detoxification
iii) Name the organ in mammals where the above reaction occurs at the highest rate (1mk)
Liver
4. You are provided with photographs A, B and C, use them to answer questions that follow.
a) Identify the parts labeled X,Y and Z. (3mks)
X…….. Humerus
Y……….Radius
Z………..Ulna
b) What common name is given to structure ref?
i) A and C…………………Analogous (1mk)
ii) B and C…………………Homologous (1mk)
c) Give a reason for your answer in b (i) and (ii) above. (2mks)
i) A and C have different embryonic origin but have been modified to perfome same function
ii) B and C have common embryonic origin but have been modified to perfome different functions
d) State the type of evolution that leads to emergence of structures named in 2 b (i) and (ii) above.
i) A and C………….Convergent evolution
ii) B and C……….Divergent evolution
e) Identify two differences between structures A and C. (2mks)
A C
Has no pentadactyl Has pentadactyl
Originate from exoskeleton Originate from endoskeleton
f) i)What is a vestigial structure? (1mk)
Structures that become functionless and reduces in size with time
ii) Give two examples of vestigial structures in human being (2mks)
Coccyx
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 Caecum and appendix
Body hairs
Ear muscles
5. Study photographs C and D and answer the questions.
d) With a reason state the agent of pollination of each of the flowers. (4mks)

Flower Agent of pollination Reason

.Inconpicuous petals
C Wind .Long featherly stigma hanging outside flower.
.Large anthers loosely attached to flexible filaments
D Insect .Brightly coloured petal
.Large and conspicuous petals
e) Classify the plants in photograph D using the taxonomic units below and reasons for your answer.
Taxonomic unit Reason

Division Spermaphyta .flowering plant

.Broad leaves
Class Dicotyledonae .Net venation
Has petiole
f) The diagrams below shows a type of cell division occurring in organisms above.
DIAGRAM STAGE REASON
A Telophase .Cell plate forms at the middle
.Chromatid collects at opposite poles
B Anaphase .Chromatids separates at centromere and migrates to opposite poles
C Metaphase .Chromosomes align at the equator
D Telophase .Cell constrict at the middle
Chromatid collects at opposite poles
(d). Giving reason, identify the kingdom to which the cell in stages A and B belongs. (2mks)
Kingdom……Plantae
Reason …Presence of cell wall
Formation of cell plate in cell A

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 SABATIA CLUSTER EXAMINATIONS
231/1
BIOLOGY
PAPER 1
(Theory)
1. State the functions of:
i) Mitochondrion (1 mark)
ii) Meristematic tissues (1 mark)
2. a) State the most suitable biological tool for collecting the following organisms:-
i) A moth from a coffee farm. (1 mark)
ii) Ants from a tree trunk. (1 mark)
3. Name two photo chemical cells in the human retina. (2marks)
4. What is meant by the following term?
a) Habitat (1 mark)
b) Ecosystem (1 mark)
5. Explain why is not advisable to be in a poorly ventilated room with a burning charcoal.
6. State two reasons why accumulation of lactic acid leads to an increase in heart beat (2marks)
7. Name three mechanisms that ensure cross pollination takes place in flowering plants (3marks)
8. The diagram below illustrates a response by a certain plant

(a) Name the type of response (1mark)

(b) Explain how the response illustrated above occurs (3marks)
9. It was found that during germination of bean seeds, 9.2 cm3 of carbon IV Oxide was produced
while 9.0 cm3 of oxygen was used up.
a) i) Calculate the respiratory quotient of the reaction:- (2 marks)
ii) Identify the substrate being metabolished:- (1 mark)
b) In which part of the cell does glycolysis occur? (1 mark)
10. A student in form three caught an organism which had the following characteristics
i) Body divided into two parts.
ii) Simple eyes.
iii) Eight legs.
Classify the organism up to the class level. (3 marks)
Kingdom Phylum Class
11. The diagram below represents complete metamorphosis in a house fly.

(a) X and Y occupies different ecological niches, state one advantage of this phenomenon.
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 (b) Name a hormone that maintains the larval stage. (1 mark)
12. State two ways through which gamete formation leads to variation. (2 marks)
13. With a relevant example, define vestigial structures (2marks)
14. Below is a nucleic acid strand

a) Name the nucleic acid (1mark)

b) Give a reason for your answer in (a) above (1mark)
c) Write down the complimentary base pairing the pattern in the nucleic acid that
formed the nucleic acid above (1mark)
15. A traffic police stretched his arm to signal a driver to stop. To cause this motion of the
arm, explain the behaviour of his biceps and triceps (2marks)
Biceps Triceps
16. Name the organism that causes
i) Bilharzia (1mark)
ii) Gonorrhoea (1mark)
17. The following is a diagrammatic representation of protein synthesis. Study it and answer the
questions that follow.

a) Name the process R. (1mark)

b) Where in the cell does R takes place. (1mark)
c) Name the:
i) Product Q (1mark)
ii) Part X (1mark)
18. a) What is the function of the following structures.
i) Spiracles. (1mark)
ii) Tracheoles. (1mark)
b) Name the substance that strengthen the trachea in insects. (1mark)
c) State two adaptations of a guard cell to its function (2 marks)
19. Which type of joint is found at the articulation of;
a) Pelvic girdle and femur. (1mark)
b) Humerus and ulna (1mark)
20. The diagram below represents a transverse section through human skin

a) Name the structure labelled; A,B (2marks)

b) State the function of part labelled C (1mark)
c) State two physiological changes that take place in a human skin in order to
facilitate heat loss from the body. (2marks)

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21. State the role played by the plug of mucus secreted by the ring of muscles of the cervix.
(1mark)
22. List down three differences between monocotyledonae and dicotyledonae plants. (3marks)
23. A group of students set up an experiment as shown below. The experimental setups were
left for 20 minutes.

The observations after 20 minutes were as shown in the table below

(a) State the process being demonstrated in this experiment. (1mark)

(b) Why was there no blue black colour inside the visking tubing in setup B? (2marks)
24. You are provided with a photograph below. Examine it carefully.

(a) State three observable features that adapt the organism to forward movement. (3marks)
25. Name a part of the brain which control Involuntary activities (1 mark)
26.
i) Write the type of gene mutation represented by the following analogue.
Intended message: BRING THERMOS ON OUTING (1 mark)
Actual message: BRING MOTHERS ON OUTING
ii) Intended message: PLEASE SAY WHERE YOU ARE (1 mark)
Actual message; PLEASE STAY WHERE YOU ARE
27.The diagram below illustrates a choice-chamber. Study it and answer the questions that follow.

i). Name the type of response exhibited by insects in the above experiment. (1 mark)
ii).Explain the observation made in the above experiment. (2 marks)
28. State three environmental factors that enhances the rate of transpiration in plants (3marks)
29. Small birds like the European robin puff up (swell up) their feathers during winter. Explain the
significance of the behavioral response. (3marks)
30. a) State an example of structures in animals whose development demonstrates adaptive
Radiation. (1mark)
b) Treatment of malaria is still a challenge in the world despite the invention of many
antimalarial drugs. Explain. (3marks)

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 SABATIA CLUSTER
231/2
Biology-(Theory)
2 hours
SECTION A (40 MARKS)
Answer all the questions in this section in the spaces provided.
1. The following diagram represents a bone from the human skeleton.

a) Identify
i) The structure (1mark)
ii) Name the parts labelled W and Z. (2marks)
b) State the role of part labelled X. (1mark)
c) Name the bone structure that articulates with Z. (1mark)
e) State three structural differences between biceps muscles and muscles of the gut. (3 marks)
2. The following diagram represents a section of the mammalian respiratory system.

a) Identify
i) the region of the mammalian skeleton where the represented section is found. (1mark)
ii) the part labelled F. (1mark)
b) State the adaptations of the part labelled E to its function. (2 marks)
c) Explain why
i) Gill rakers in a bony fish are closely packed and face the mouth. (2 marks)
ii) Fish gill filaments are long and numerous. (1 mark)
d) Name the causative agent of amoebic dysentery. (1Mark)
3. In an investigation, students placed sodium hydroxide pellets in a conical flask that had a mesophyte
leaf that had been kept in the dark place for 48 hours and corked it as shown in the following
experimental set up.

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a) State the aim of the experiment. (1mark)
b) What is the function of sodium hydroxide pellets in the set up? (1mark)
c) leaf A and B were tested for the presence of starch.
i) state the observations made after the test of:
leaf A (1mark)
Leaf B (1mark)
ii) Name the reagent used to test for the presence of starch. (1 mark)
d) Why was the potted plant kept in the dark for 48 hours before the set up was made. (1mark)
e) Name two factors that affect the process being investigated in the set up above. (2 marks)
4. a) How many sex chromosomes are there in each human somatic cell. (1 mark)
b) What is meant by the term sex linkage? (1 mark)
c) Haemophilia is due to a recessive gene that is sex linked. In a family where both parents were
normal, one of the sons was haemophilic.
i) Using letter H for normal blood clotting gene, work out the genotype of the children.
ii) What is the probability of a child born of this couple being a boy and haemophilic?
d) Explain why haemophilic is more common in males than in females. (1 mark)
5.a) What is organic evolution? (1 mark)
b) Give one example of the following structures. (2 marks)
i) Homologous structures.
ii) Analogous structures.
c) In rice fields, weeds are normally removed by hand when rice plants are still young, one common
weed in a rice species of barnyard grass which has a close resemblance to young rice plants. Unlike
most other weeds, this species spreads very fast wherever it is newly introduced.
i) What adaptive variation confers confers a selective advantage of this species of barnyard grass.
(1 mark)
ii) Why does the weed spread very fast? (2 marks)
d) In what way does Lamarck’s theory fail to agree with modern scientific evidence. (1 mark)
e) Name one evidence of organic evolution. (1 mark)
SECTION B (40 MARKS)
Answer question 6 (compulsory) and either of question 7 or 8 in the space provided after question 8.
6. The concentration of lactic acid in blood during and after an exercise were determined. The results
were as recorded in the table below.
Time in minutes 0 5 10 15 20 25 30 35 40 45 50 55
3 20 50 80 98 86 78 70 68 62 58 54 50
Concentration of lactic acid (mg/100cm )

a) On the grid below, draw the graph of the concentration of lactic acid in blood against time.
b) i) By how much did the lactic acid increase at the end of 13 minutes. (1mark)
3
ii) After how many minutes was the lactic acid concentration 71mg/cm . (1 mark)
iii)What would be the concentration of lactic acid at the 60th minute. (1 mark)
c) i) Give a reason for the high rate of lactic acid production during the exercise. (2 marks)
ii) Give a reason for the decrease in the concentration of lactic acid after the exercise.
d) State two differences between aerobic respiration and anaerobic respiration. (2 marks)
e) Name a site of energy production in an animal cell. (1 mark)
f) Define the following terms
i) Oxygen debt (1mark)
ii) Respiratory quotient. (1mark)
g) In mammals, Haemoglobin is confined in the red blood cells. Give one advantage of this.
(h) A dog weighing 20kg requires 200kj per gram body weight while a mouse weighing 50g requires
3000kj per gram body weight. Explain. (2 marks)
7. Describe the structure and function of the mammalian skin. (20 marks)
8. Explain how the abiotic factors affect plants. (20 marks)

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 SABATIA CLUSTER EXAMINATION
231/3-BIOLOGY
PAPER 3
(PRACTICAL)
CONFIDENTIAL
Each candidate requires the following:
1. Solution Q (Starch solution) – 10ml
2. Solution W (glucose solution) – 50ml
3. Specimen D (Femur –mammalian- one for every five students)
4. 10 cm Visking tubing
5. Two pieces of thread – 15cm
6. Four test tubes in a rack
7. Two labels
8. Two empty beakers
9. Iodine solution – 2ml
10. Benedict’s solution – 8ml
11. Test tube holder
12. Access to source of heat/ hot water bath
13. Stirring rod
14. 10ml measuring cylinder
15. Dropper
16. Water in a wash bottle.

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 SABATIA CLUSTER EXAMINATION
231/3
BIOLOGY
(PRACTICAL)
TIME: 1 3/4 HOURS
1. (a). You are provided with solution Q, Solution W, visking tubing and a thread. Divide solution
Q and W into two halves in separate beakers. Use one half for procedure I and second half for
procedure II.
Procedure I
(i). Using reagents provided and one half of solution Q and W carry out tests to determine the food
substance present in solution Q and W.
(ii). Record the procedure, observations and conclusion in the table below. (8mks)

Test Food solution Procedure Observation Conclusion

Starch Q
W
Reducing sugar Q
W
Procedure II.
Clean and rinse properly any of the beakers that contained solution W or solution Q for use in this
procedure.
i). Tie one end of visking tubing provided with a thread tightly.
ii). Measure about 5ml of solution Q into the visking tubing (Stir the solution thoroughly before use).
iii). Tie the other end tightly to ensure that there is no leakage.
iv). Immerse the visking tubing and its content into a beaker containing solution W.
v). Allow it to stand for 20 minutes.
vi). After 20 minutes empty the content of the visking tubing into a clean empty beaker.
(b). i). Use the solution that was in the visking tubing to test for starch and reducing sugars.
Record the observations and conclusions in the table below (4mks)
ii). Name the physiological process being investigated in the experiment. (1mk)
iii). Which structure in the living organism is represented by the visking tubing? (1mk)
2. Examine the photograph which shows a section through a female urinogenital system and answer the
questions that follow:

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(a). (i). Name the part marked J. (1mk)
(ii). State Two functions of the part named in a(i) above and how its adapted to its function.
(2mks)
(b). i). Name the part marked K. (1mk)
ii). Explain the One function of the part named in b(i) above. (1mks)
(c). i) Identify the organ marked L. (1mk)
ii). State Two functions of the organ named in c(i) above. (2mks)
(d). State Two functions of the organ marked M. (2mks)
(e). i). State Two ways through which HIV/AIDS virus is transmitted. (2mks)
ii). Positive change in behavious in human being is likely to prevent the spread of AIDS.
State Two ways in which this can be done. (2mks)
3. (a). You are provided with specimen D, a mammalian bone. Examine it and use it to answer the
questions that follow.
(i). Identify the bone. (1mk)
(ii). Draw a neat labelled diagram of the bone. (3mks)
(b). Study the diagram below and answer the following questions.

i). Name the muscles labelled A and B. (2mks)

ii). Explain what happens to each muscle as the arm is straightened? (2mks)
iii).Which of the muscles A and B is a flexor muscle? (2mks)
iv) Apart from the type of muscle represented by A and B name one other muscle found in the human
body (1mk)
(c). Examine the photograph shown below.

(i). Name the response shown by the plant X. (1mk)

(ii). What is the biological significance of the response stated in (i) above to the plant?
(1mks)

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 SABATIA CLUSTER EXAMINATIONS
231/1
BIOLOGY
PAPER 1
MARKING SCHEME
1. State the functions of:
i) Site for respiration/site for respiratory reactions that yield energy for the cell
ii) Site for growth in plants
2. a)
i) Sweep net
ii) pooter
3. a) Cones
Rods
4. What is meant by the following term?
a) Specific locality with a particular set of conditions where an organism lives
b) A natural unit composed of abiotic and biotic factors whose interactions lead to a self sustaining
system
5. Burning charcoal produces CO;CO combines with haemoglobin to form carboxyhaemoglobin which
does not dissociate;limiting the capacity of haemoglobin to transport oxygen leading to suffocation;
6. Increase in heaart beat to increase extra supply of oxygen;to breakdown toxic lactic acid to less toxic
CO2 and water;
7. Protandry
Protogyny
Self sterility/incompatibility
heterestyly
8.
(a) Thigmotripism/haptotropism
(b) Contact causes auxins to migrate to the opposite side;high concentration of auxins on the side with
no contact stimulates faster elongation of the shoot;leading to coiling;
9. a)
i) RQ = CO2 Pr oduced
CO2 Pr oduced
= 9.2 =1.0222= 1
9
ii) Carbohydrates
b) Cytoplasm
10. A student in form three caught an organism which had the following characteristics
i) Body divided into two parts.
ii) Simple eyes.
iii) Kingdom…… Animalia. Rej: Animal or if first letter is small letter
Phylum……… Arthropoda rej. Anthropoda / Athropoda / Arthropod, if first letter is small letter
Class……… Arachnida
11.
(a) To reduce competition for food
(b) Juvenile hormone
12. Crossing over
Independent assortment
13. Structures that have over time ceased to function hence reduced in size and have become
rudimentary
 Appendix in humans
 Absence of limbs in python and whale
 Flightless birds/kiwi and emu

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 Coccyx in humans
14. a) Ribonucleic acid; rej RNA
b) Presence of uracil
c) T – C – G – G – T – G – C;
15. Triceps – contract;
Biceps – Relax;
16. i) Amoebic dysentery. Entamoeba hystolytica
ii) Gonorrhoea Neisseria gonorrhoea acc bacteria
17. a) Condensation ;
b) Ribosome ;
c) i) Q- Polypeptide
ii)X - Peptide bond ;
18 a) i) Allow air in and out of the trachea;
ii)Site for gaseous exchange ;
b) Chitin;
c) Has thick inner wall and thin outer walls to control opening and closing of stomata
Has chloroplasts to carry out photosynthesis/ manufacture of glucose that alters osmotic
pressure bringing about opening and closing of stomata
19. a) Ball and socket
b) Hinge joint
20. a) A………… sebaceous gland;
B………… Horny / cornified layer
b) sweat gland; Are involved in body temperature regulation through loss of excess heat by
evaporation of water.
c) Sweating / secretion of sweat; any two (2mks)
Vasodilatation/ re – direction of blood into the skin;
Relaxation of erector (pili) muscle/ hair lies low/ flat/ flattens;
21. Prevents entry of pathogens into the uterus during pregnancy
22.
Monocotyledonae Dicotyledonae
Narrow leaves Broad leaves;
Leaves parallel veined Leaves net veined;
Vascular bundles scattered Vascular bundles arranged in a ring;
Floral Parts in threes Floral parts in fours or fives or their multiples;
or multiples of three
Cambium absent Cambium present;
Phloem and Xylem alternate each other In roots xylem (star- shaped) at the centre as
in a ring in root phloem alternates with the arms of xylem;
Absence of pith Presence of pith;
(mark 1st three)
(N:B complete difference to earn a mark)
23.
(a) Diffusion
(b) Boiling stach in dilute HCL hydrolysed starch to maltose;starch was absent
24.
(a) Scales overlapping and facing backwards
Tail fin
Pectoral fin
Inflexible head
Streamlined body
25. Medulla Oblongata
26. (a) inversion

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 (b) insertion
27. i). Positive chemotaxis
ii). Naphthalene repels ants; hence they move towards the sugar; //
Sugar attracts insects; hence they move towards sugar;
28. High wind speed
High temperature
Low humidity
High light intensity
29. To reduce heat loss; since the feathers trap more air; that acts as insulator;against heat loss/ that is a
poor conductor of heat.
30. a) Pentadactyl limbs; the feet of birds; the beak of birds; mark any one correct
b) Some parasites mutate; to acquire the gene for resistance; to the drugs used.
(The ones without the gene are eliminated by the drugs) The ones with the resistant gene
acquire a selective advantage to survive to maturity; and their offspring inherit the genes; A
new population of resistant parasites is hence developed; OWTTE max 3mks

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 SABATIA CLUSTER EXAMINATIONS
231/2
BIOLOGY
PAPER 2
MARKING SCHEME
1. a) i) pelvic girdle; (1mark)
ii) W ischium; (2marks)
Z IIium;
b) Articulates with the head of the femur;(to form a ball and socket joint) (1mark)
c) Sacrum; (1mark)
d) (3marks)
Biceps Muscles of the gut
Have striations /stripes Lack striations /stripes;
Multinucleated Mononucleated;
Cylindrical cells Spindle shaped cells;
2. a) i) Thoracic/chest region; (1mark)
ii) pleural membranes; (1mark)
b) made up of C shaped rings of cartilage which ensures that it does not collapse during
breathing; lumens of the trachea are lined with ciliated epithelium, that beats in waves and
move the mucus and foreign particles towards the pharynx away from the lungs;
c) i) To trap/filter solid/foreign particles out of the water flowing over the gills; in order to
protect the delicate gill filaments from being damaged by the particles; (2marks)
ii) To provide a large surface area for gaseous exchange; (1mark)
d) Entamoeba hystolytica; (1mark)
3 a) To investigate carbon (lv) oxide is necessary for photosynthesis; (1mark)
b) Sodium hydroxide pellets absorb water to form a solution that absorbs carbon (lv) oxide
readily;
c) i) leaf A (2marks)
Retained iodine solution colour/brown;
leaf B
Blue black colour seen;
ii) iodine solution; (1mark)
d) To ensure all the starch in it is used up/destarching; (1 mark)
e) light intensity;
Temperature; (2marks)
Water availability; (mark the first two)
Chlorophyll concentration;
4. a) Two sex chromosomes (1mark)
b) Genes are located on the sex chromosomes and are transmitted together with those that
determine sex; (1mark)
c) i) (4marks)
father mother
H H h
X Y X X X
ii) ¼ or 25%; (1mark)
d) Males require to have only one haemophilic gene, which they can get from a carrier mother to get
the disease. Females must have two such genes, one from the father and one from the mother. There
are very little chances of the females inheriting the haemophiliac gene from the father;
5 a) Emergence of present species of organisms from pre-existing ones through gradual
transformation over a long period of time; (1 mark)
b) i) forelimbs of different groups of vertebrates; (1mark)
ii) wings of insects and those of birds; (1mark)
c) i) resemblance to rice plants; (1mark)
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 ii) humans mistake the weed for rice plants and fail to remove it. This allows it to survive to
maturity and reproduce forming seeds which are dispersed to other areas; (2marks)
d) Acquired characteristics cannot be passed on from parents to off springs;
e) fossil records; (2marks)
geographical distribution;
comparative anatomy;
comparative embryology;
cell serology;
6. a) graph (6marks)
Axis (2marks)
Scale (2marks)
Curve (1mark)
Plotting (1mark)
Total (6marks)
3
(b) i) 90mg/100cm (1mark)
ii) 8th minute (1mark)
3
iii) 46mg/cm (1mark)
(c) i) The individual was carrying out anaerobic respiration, partial combustion of glucose took
place; (1mark
ii) Anaerobic respiration stopped, due to oxygen debt; (1mark)
(d) (2marks)
Aerobic respiration Anaerobic respiration
Oxygen required for complete oxidation Oxygen not required, incomplete oxidation;
High amounts of energy produced Low amount of energy is produced;
Carbon (lv) oxide and water produced Lactic acid or alcohol produced;
Complete combustion of substrate Partial combustion of substrate;
Water molecules are produced Water molecules are not produced;
Over a short period of time, energy is not Over a short period of time, energy is
released released;

Mark the first two

e) Cytoplasm; (1mark)
f) i) Oxygen required to get rid of the lactic acid that accumulates in the body tissues when supply
of oxygen is less than the demand; (1mark)
ii) Ratio showing relationship between the amount of carbon (lv) oxide used against oxygen
consumed in respiration; (1mark)
(g) if haemoglobin were dissolved in plasma, the osmotic pressure of blood would increase. This would
interfere other physiological processes.
If haemoglobin were dissolved in plasma, the viscosity of blood would increase. This would require
the heart to work much harder to pump blood throughout the body; (1mark)
h) Alcohol and energy; (1mark)
(i) A mouse has a large surface area to volume ratio than the dog; it looses more energy per unit body
weight /loses heat faster than the dog; (2marks)
7. It has cornified layer; made up of dead cells; and is impermeable to water; to protect the skin against
mechanical damage; bacterial infections; and water loss.;
Granular layer; whose cells divide to form the cornified layer;
Malpighian layer; which is made up of dividing cells; that give rise to a new granular layer;
Contains melanin; to protect the skin against ultra violet rays/radiations;
Sebaceous glands; which secrete sebum; to make the skin supple/soft and waterproof;
Blood vessels; dilate during hot weather; increasing blood flow near the skin surface; heat loss is
enhanced, constrict in cold weather, less blood flow, minimize heat loss;
Sensory nerve endings and receptors; enable detection of environmental changes;
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 Highly coiled sweat glands; secret sweat; to control body temperature when hot sweat evaporates
cooling the body.;
Sweat contains excretory products;
Subcutaneous fat/adipose tissue in dermis for insulation;
Hair; to regulate body temperature in cold weather;
Erector pili muscles contract; hair is raised, air trapped to insulate the body;
In hot weather, erector pili muscles relax; hair lies flat reducing insulation;
Dense network of blood capillaries; supply nutrients; and oxygen; to skin tissues; as well as carrying
away nitrogenous wastes; and carbon (lv)oxide; away from the skin tissues;
Adipose tissue/subcutaneous layer; serves as an insulation helping in temperature control;
Skin helps in manufacture of vitamin D; (20marks )
8. Wind;
In windy conditions the rate of transpiration increases;
Wind disperses fruits and seeds;
Wind is an agent of pollination;
Temperature;
Changes in temperature affects the rate of photosynthesis and other biological reactions;
Increase in temperature increases the rate of transpiration;
Light;
Green plants need light for photosynthesis;
Some plants need light for flowering;
Seeds like lettuce require light for germination;
Humidity;
When humidity is low, rate of transpiration increases;
H
P ;
Each plant requires a specific P H to grow well either in acidic or alkalinity or neutral P H;
Salinity;
Only plants with salt tolerant tissues like mangrove grow in saline areas;
Plants that grow in estuaries adjusts to salt fluctuations;
Topography;
In temperate regions, north facing slopes have more plants than south facing slopes because they are
warmer. ;The reverse is true in Northern hemisphere
The windward side has more plants but they may have distorted growth to being constantly blown by
wind;
Rainfall/water/rain;
There are fewer plants in deserts where rainfall is less;
Water is required for germination and photosynthesis;
Water acts as a transport medium and make the cells turgid for support;
Atmospheric pressure;
At higher altitudes, atmospheric pressure is low which increases the rate of evaporation resulting in
high rates of transpiration;
At higher altitudes, atmospheric pressure is low and consequently the levels of both carbon (lv)
oxide and oxygen is low;
This limits the plants that can grow at high altitudes;
Mineral salts;
Plants thrive best where there are sufficient mineral salts in the soil;
Plants growing in soils deficient of particular elements may have special methods of obtaining it;

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 SABATIA CLUSTER EXAMINATION
MARKING SCHEME
231/3
BIOLOGY
PAPER 3
(PRACTICAL)
(1).
Test Food Procedure Observation Conclusion
solution
Starch Q To 2ml of solution Q Blue-black Colour Starch
add drops of Iodine present
solution.

W To 2ml of solution W Yellow Brown Colour Starch Absent

add drops of Iodine
solution.
Reducing sugar Q To 2ml of solution Q Blue Colour Reducing sugar
add a good amount of Absent
Benedict’s solution,
shake to mix and heat
to boil.
W To 2nd of solution W Colour changes to Reducing sugar
add an equal amount yellow/ Orange/ present
of Benedict’s Brown
Solution, shake to mix
and heat to boil.
2.
(a). (i). -Urinary bladder (1mk)
(ii). Functions as a temporary vessel for urine to delay frequency of urinations.
It is elastic and can increase its volume greatly to accommodate a large amount of urine.
b). i). Ovary (1mk)
ii). Site for production of ova/female gametes secondary o cycles.
Secretion of hormones
c). i) Uterus (1mk
ii). Site for implementation
Nourishment and development of the uterus.
d). Site for absorption of water
Site for absorption of vitamins K12, B and riboflavin.
Package indigestible matter into faeces
(e). (i). (2mks)
- Sexual intercourse with infected partner.
- Unsterilized skin piecing instruments.
- Infected mother to child at birth or through breast milk.
- Blood transfusion from an infected person.
(ii). (2mks)
- Avoid indiscriminate sex/Abstinence
- Use of condoms if sex is unavoidable.
- Avoid drug abuse which can predispose one to HIV infection.
- Be faithful to your uninfected lawful partner.
3. (a). (i). Femur (1mk)

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(ii). Draw a neat labelled diagram of the bone. (3mks)

b). i). A: Biceps

B: Triceps
ii). A (Biceps) relaxes; while B (triceps) contracts;
iii). A; (Biceps)
iv) smooth muscles
cardiac muscles
(c).
(i). Thigimotropism/haptropism.
(ii). It enable the plant to access support so that it can rise to upper levels where it can expose its
leaves to light for photosynthesis, flowers in a position for effective pollination and fruits in a
position for effective dispersal.

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 SUPERIOR JET
231/1
BIOLOGY
PAPER 1
1. Name a branch of biology that deals with how characteristics and qualities of parents are given to the
children in living organisms.
2. a) Give the significance of first and second meiotic division. (2mks)
i) Meoisis I
ii) Meoisis II
b) Distinguish between synapsis and crossing over. (2mks)
3. State two principles a candidate should apply when writing a scientific name in biology exam.
(2mks)
4. Healthy plant was kept in the dark for 24 hours then two of its leaves were enclosed in a glass flask
as shown. The plant was then returned in the light

a) Give the functions of the following in the experiment.

i) Sodium hydrogen carbonate. (1mk)
ii) Sodium hydroxide. (1mk)
b) Explain the results expected after 24 hours when leaf A was tested for starch. (2mks)
5. Give two biological ways through which plants carryout nitrogen fixation. (2mks)
6. The equation below represents a reaction which occurs during strenuous physical activities in human
muscles.
Glucose Compound P + 150kj

a) Give one effect of the above reaction to an individual. (1mk)

b) State one way in which compound P is eliminated from the muscle tissue. (1mk)
7. What are the three climatic factors that reduce transpiration in plants? (3mks)
8. Below is a representation of stage through which a certain insect undergo in its life cycle.

a) Identify the type of metamorphosis exhibited by the insect. (1mk)

b) State two morphological differences between stage B and D. (2mks)
9. a) State the importance of leaf mosaic in mesophytes. (1mk)
b) State the adaptations that make hydrophytes buoyant. (1mk)
10. The table below shows the approximate amount of red blood cells in the blood of a person living in
different places for different periods of time.
Duration Altitude Millions of red blood cells /mm3
2 years sear level 5.0
2 years 5000m 7.3
1 week 5000m 5.9
a) Account for the difference in the amount of red blood cells in the person when living t sea level for 2
years and at 5000m for the same period of time. (2mks)

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b) What other difference would be between a person at sea level and living at 5000m for a week.
11. Give two reasons why members of kingdom Fungi are separated from those in kingdom Plantae.
12. Diagram A and B represent a human arm and bird wing respectively.

a) Name the joint found at part labeled X. (1mk)

b) Which bones in human arm are equivalent to part labeled 1 and 2 in bird wing? (2mks)
c) Identify the type of evolution that lead to existence of types of structure shown by limbs in human
and birds. (1mk)
13. A gen Z demonstrator was hit by a fast moving vehicle while on street and afterwards, he had the
following conditions:
Could not recall his name, was consigned to wheel chair and was unable to perceive food taste.
Name three parts of his brain affected by accident that led to.
a) Inability to recall his name. (1mk)
b) Consignment to wheel chair. (1mk)
c) Inability to perceive food taste. (1mk)
14. The table below shows a form 1 student summary of photosynthesis process. Complete the table by
filling the missing information. (3mks)
Stage Site of chloroplast Reaction Products
Light dependent Grana - 4TP molecule
hydrogen atom,
oxygen gas
Light independent - Carbon (iv) oxide -
fixation

15. The diagram below repents animal cells.

Explain the role of the above cells in the (3mks)

a) Gut
b) Eye
c) Oviduct
16. State one adaptation of the following parts of nephron to ultrafiltration. (2mks)
a) Glomerulus
b) Afferent and efferent arteriole.
17. A mother of a blood group O gave birth to a child who was taken to nursery. After two days she was
convinced that her baby had been exchanged with another one.
a) Name one genetic based technique which could be used to solve the above impase. (1mk)
b) If the baby she was given has a blood group A and the father blood group was homozygous blood
group B, identify whether the woman was justified ( use genetic cross) (3mks)
18. Explain how a plant cell is made flaccid. (3mks)
19. Name the method used by plants to eliminate the following. (3mks)
a) Gum
b) Water droplets
c) Papain

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20. A chamber was divided into two. Equal numbers of maggots were placed on each side of the
chamber and then each side covered with different materials as shown. The chamber was then placed
in an illuminated room. The process shows the direction of maggots movement.

a) Name the response exhibited by maggots. (1mk)

b) State the biological importance of the response identified in (a). (1mk)
21. A student enters a dusty room and immediately develops severe itching and irritation of nasal cavity
followed by sneezing and difficulty in breathing.
a) Name the body reaction caused by dust in the student
b) Explain how the reaction occurs in the body. (2mks)
c) State the treatment recommended for the reaction. (1mk)
22. The diagram below represents internal structure of maize gain.

a) Classify the above fruit. (1mk)

Name the structures that protect part E and F during germination. (2mks)
23. a) Name a feature in human lungs which
i) Provide large surface are for gaseous exchange. (1mk)
ii) Aid faster diffusion of gasses. (1mk)
b) Suggest why asthma patients experience difficulty in breathing. (1mk)
24. A patient was diagnosed with tuberculosis after which the doctor prescribed antibiotics for him. He
was to take prescribed antibiotics for him. He was to take antibiotic drugs for six continuous days but
took antibiotic drugs and suddenly stopped on the third day. When he went back for further checkup,
lab tests revealed that the pathogen load in his system had up surged by 50%.
a) Name the pathogen that was abundant in his system during infection. (1mk)
b) Account for the results for the send test. (2mks)
25. Explain the condition under which each of the organs in human reproduction system. Show great
increase in size. (2mks)
a) Uterus
b) Penis
26. Describe the role of antidiuretic hormone in selective reabsorption when osmotic potential of the
body fluids rises above optimum. (3mks)
27. Explain how the following parts of light microscope contribute to the formation of image of the
specimen.
a) Condenser. (1mk)
b) Mirror (1mk)
c) Objective lens (1mk)
28. How is mechanical digestion achieved in the following parts of alimentary canal
a) Mouth (1mk)
b) Stomach (1mk)
c) Duodenum (1mk)

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 SUPERIOR JOINT EXAMINATION
BIOLOGY
THEORY
Paper 2
Time: 2 hours.
1. a) When pure breeding white horse was mated with pure breeding red horse, all the offspring had
roan coat colour. Using letter G to represent gene for red coat and H to represent white coat
hair.
Work out the genotypic ratio of F2 generation. 5 marks
b) Give reasons why Fruit fly is suitable organism for genetic study. 1 mark
c) Describe two reasons why gene sequencing is important? 2 marks
2. An athlete training to take part in an international competition moved to a high altitude area where
he was to train for twelve (12) days before the competition. He took his pulse rate per minute daily
and tabulated them as shown below
DAY 1 2 3 4 5 6 7 8 9 10 11 12
PULSE PER MIUTE 72 77 89 92 92 90 86 80 77 74 72 72
a) Other than pulse rate, name one other process which was affected by change in altitude.
b) Account for the change in pulse rate from.
i) Day 1 to Day 7 2 marks
ii) Day 8 to Day 12 1 mark
c) Explain the advantage this athlete has over the one who trains in a lower altitude area.
d) The equation below represents a reaction which takes place during rapid muscular movements in
humans.
Glucose → Lactic acid + 150kJ
(i) State the effect of this reaction to an individual. 1 mark
(ii) How is Lactic acid finally eliminated from the muscle tissue after the muscle return to normal
movement? 1 mark
3. The diagram below shows the ultrametric of a section of a cell membrane.

a) Give two functions of the cell membrane. 2 marks

b) Name the parts labelled 2 marks
c) Why does the nucleus of a cell have many pores? 1 mark
d) Explain what happens to the function of the structure illustrated when subjected to high temperature
above 500C. 2 marks
e) Why are the cell membranes polarized? 1 mark
4. a) The diagram below represents the female urinogenital system.

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(i) Name the parts labeled 4 and 8. 2 marks
(ii) State the functions of each of the parts labeled 1 and 7. 2 marks
(iii) Explain two adaptations of the part labeled 2 to its functions 2 marks
(b) Explain the events that occur in the part marked 1 following conception. 2 marks
5 a) The diagram below illustrates the transverse section of a stem of a plant.

i) Name the class to which the plant belongs. 1 mark

ii). State two differences between the tissue in the region labeled R and the region marked T.
2 marks
b) Describe the role of the unpaired fins in preventing yawing and rolling in fish. 1 mark
c) The diagram below illustrates a human joint. Study it and answer the questions that follow.

D
1

A
B
E

F F

D
2

i) State two components of the type of joint joint illustrated above 2 marks
ii). State the function part labeled F. 1 mark
iii). State the significance of structure B at this joint. 1 mark
SECTION B (40 marks)
Answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after question 8.
6. The table below shows data obtained from an experiment to investigate how the rate of
photosynthesis affects uptake of chloride and nitrate ions by a certain plant species.

Rate of photosynthesis (sugar

formed per unit time) 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
Rate of uptake of Nitrate 20 34 47 60 66 72 72 72 72
ions (mg/min) Chloride 48 48 48 48 48 48 48 48 48
a) Plot a graph of rate of chloride and Nitrate ions against photosynthesis. 8 mark
b) With a reason in each case, identify the physiological process by which the above plant species
absorbs;
i) Chloride ions 2 marks
ii) Nitrate ions 2 marks
c) Account for the uptake of Nitrate ions by the plant between;
i) 0.2 – 0.8 units 3 marks
ii) 1.0 – 1.8 units
d) Explain why osmosis experiments involving animals are mostly carried out using blood cells and not
any other cell. 2 marks
7. Describe how the mammalian Gaseous exchange system is adapted to its function. 20 marks
8. a) Describe the process of accommodation for a distant object 5 marks
b) Describe water pollution under the following headings.
i) Causes 5 marks
ii) Effects 5 marks
iii) Control measures 5 marks

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 THE SUPERIOR JET
CONFIDENTIAL
231/3
BIOLOGY
Each candidate requires the following:
• A sharp scalpel
• 2 Irish potato cylinders each measuring about 4 cm long
• ½ medium sized piece of Irish potato
• About 8 cm3 of 3 % hydrogen peroxide solution
• About 8 cm3 of sodium hydroxide solution
• Access to iodine solution and a dropper
• Access to DCPIP
• (Access) to means of timing
• A 10ml measuring cylinder
• A white tile
• A motor and a pestle
• 4 test tubes in a rack
• 3 labels
• Glass rod
• Distilled water in a wash bottle
• An empty beaker

THE SUPERIOR JET

231/3
Paper 3
BIOLOGY (Practical)
1. You are provided with the following materials:
• A sharp scalpel
• 2 Irish potato cylinders
• A medium sized piece of Irish potato
• 3 % hydrogen peroxide solution
• Sodium hydroxide solution
• Iodine solution and a dropper
• DCPIP solution
• (Access) to means of timing
• A 10ml measuring cylinder
• A white tile
• A motor and a pestle
• 4 test tubes in a rack
• 3 labels
• Glass rod
• Distilled water in a wash bottle
• An empty beaker
Procedure:
(i) Label two test tubes 1 and 2.
(ii) Cut to obtain a piece measuring 2 cm long from each of the two Irish potato cylinders provided.
Discard the remaining parts of the cylinders.
(iii) Separately macerate (chop into tiny pieces) the two pieces obtained in (ii) above.
(iv) Place equal amounts of the macerated pieces into test tube 1 and 2.

Page | 312
(v) Add about 2 cm3 of sodium hydroxide solution into each of the test tubes 1 and 2.
(vi) Add 2 cm3 of distilled water into test tube 1 and 6 cm3 of distilled water into test tube 2.
(vii) Add 2 cm3 of the 3 % hydrogen peroxide solution provided into each of the test tubes 1 and 2 and
leave the setups to stand for 5 minutes.
(a) i) Record your observation in test tube 1 and 2 after 5 minutes. (2 marks)
ii) Account for the observations in (a) (i) above.
test tube 1 (3 marks)
test tube 2 (2 marks)
(b) State how the experiment in test tube 2 would be modified to obtain similar results to test tube 1.
(2 marks)
Use the Irish potato provided for part (c) below:
Procedure:
• Peel the Irish potato provided and cut it into tiny pieces.
• Crush the pieces in a motor using a pestle.
• Add about 10 cm3 of water and stir
• Decant the extract into an empty beaker.
(c) Use the reagents provided to test for the food substances present in the extract from the potato and
complete the table below.
Food substance Procedure Observation Conclusion

2. The photographs A and B below show different plant responses in seedlings. Examine them.

(a) Name the type of responses shown by plants in photographs A and B. (2 marks)
Explain how the responses exhibited by the plants in photographs A and B occurred.
(i) Photograph A (3 marks)
(ii) Photograph B (3 marks)
(b) State the biological importance of the response shown by the plant in photograph A above.
3. Below are two photographs labeled J and H. Photograph J shows a bone obtained from a
mammalian body while H shows bones at a joint found in the hind limb of a mammal.

Page | 313
(a) (i) State the identity of bone J. (1 mark)
(ii) Using observable features on photograph J only, give two reasons for your answer in
(a) (i) above. (2 marks)
(b) How is the bone in photograph J adapted to its functions? (3 marks)
(c) Name the bones labeled 1, 2 and 3 on photograph H. (3 marks)
(d) State the role of the bone labelled 2 at the joint. (2 marks)
(e) (i) Name the fluid found in the part labeled 4 on photograph H. (1 mark)
(ii) What are the functions of the fluid found in the part labelled 4? (3 marks)

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 SUPERIOR JET
BIOLOGY
231/1
PAPER 1
MARKING SCHEME
1. Name a branch of biology that deals with how characteristics and qualities of parents are given to the
children in living organisms.
Genetics
2. a) Give the significance of first and second meiotic division. (2mks)
a. Mesisis II
Separates homologous chromosomes
b. Meiosis II
Separates sister chromosomes
b) Distinguish between synapsis and crossing over. (2mks)
synapsis is a process by which homologies chromosomes lie side by side to form bivalent; crossing
over is the exchange of genetic material at chiasmata.
3. State two principles a candidate should apply when writing a scientific name in biology exam.
- Organisms given two names, generic and specific
- Generic name start with a capital letter specific name in small letters;
- Names underlined separately
4.
a) Give the functions of the following in the experiment.
i) Sodium hydrogen carbonate. (1mk)
Add carbon (IV) oxide to air in flask B;
ii) Sodium hydroxide. (1mk)
Absorbs/ remove carbon (IV) oxide from flask A;
b) No starch photosynthesis did not take place due to absence of CO2
5. Give two biological ways through which plants carryout nitrogen fixation. (2mks)
- Through actions of free living bacteria such as clostridium
- Through action of symbiotic bacteria such as phizobium
- Through action of some algae such as anabeana;
6.
a) Give one effect of the above reaction to an individual. (1mk)
- Causes muscular fatigue
- Causes muscle crumps;
b) State one way in which compound P is eliminated from the muscle tissue. (1mk)
- Converted to glycogen in the liver
- Oxidized to release energy;
7. What are the three climatic factors that reduce transpiration in plants? (3mks)
- Low temperature
- High humidity
- Low light intensity
- Weak air current/still air/high atmospheric pressure;
8.
a) Identify the type of metamorphosis exhibited by the insect. (1mk)
- Incomplete metamorphosis
b) State two morphological differences between stage B and D. (2mks)
- B is smaller in size while D is larger in size
- B lack wings while D has wings;
9. a) State the importance of leaf mosaic in mesophytes. (1mk)
- To trap/receive maximum amount of sunlight for photosynthesis;
b) State the adaptations that make hydrophytes buoyant. (1mk)

Page | 315
- Air spaces in tissue/aerenchyma tissue;
- Reduction of supporting tissue callencyma/parenchyma/xylem;
10.
a) Account for the difference in the amount of red blood cells in the person when living t sea level for 2
years and at 5000m for the same period of time. (2mks)
- At high altitude oxygen concentration is low in the air, number of RBC increase to increase capacity
of blood to transport more oxygen;
b) What other differences would be between a person at sea level and living at 5000m for a week.
(1mk)
- Increase in amount of haemoglobin;/faster and deep breathing in person at 5000m.
11. Give two reasons why members of kingdom Fungi are separated from those in kingdom Plantae.
(2mks)
- Fungi are heterotrophic while plantae are autotrophic;
- Fungi body is mycelium while plantae body is compact/branched
- Fungi lack chlorophyll;
12. Diagram A and B represent a human arm and bird wing respectively.
a) Name the joint found at part labeled X. (1mk)
- Hinge;
b) Which bones in human arm are equivalent to part labeled 1 and 2 in bird wing? (2mks)
- Humerus;
- Radius;
c) Identify the type of evolution that lead to existence of types of structure shown by limbs in human
and birds. (1mk)
- Divergent;
13. A gen Z demonstrator was hit by a fast moving vehicle while on street and afterwards, he had the
following conditions:
Could not recall his name, was consigned to wheel chair and was unable to perceive food taste.
Name three parts of his brain affected by accident that led to.
a) Inability to recall his name. (1mk)
Cerebellum;
b) Consignment to wheel chair. (1mk)
- Cerebrium;
c) Inability to perceive food taste. (1mk)
- Cerebrum
14. Site-stroma;
Reaction- water photolysis
Products- glucose, amino acids,fatty acids and glycerol;
15. The diagram below repents animal cells. (3mks)
a) Gut
- Contract and relax to bring about peristalisis hence movement of food;
b) Eye
Contract and relax to alter the diameter of the pupil hence regulating the amount of light reaching
relina;
c) Oviduct
- Contract and relax to generate force that pushes the ovum/zygote towards uterus;
16. State one adaptation of the following parts of nephron to ultrafiltration. (2mks)
a) Glomerulus
- Made up of fine network off blood capillaries that are highly branched to increase surface area for
ultrafiltration;
b) Afferent and efferent arteriole.
- Efferent arteriole has narrow lumen that efferent arteriole to create resistance to blood flow thus
generating pressure for ultrafiltration. (OWTTE)

Page | 316
17. A mother of a blood group O gave birth to a child who was taken to nursery. After two days she was
convinced that her baby had been exchanged with another one.
a) Name one genetic based technique which could be used to solve the above impase.
- Blood typing;/ DNA finger printing/test
b) If the baby she was given has a blood group A and the father blood group was homozygous blood
group B, identify whether the woman was justified ( use genetic cross) (3mks)

BB X OO

B B O O

BO BO
BO BO
- All children have blood group B
- The baby was exchanged and the women was justified since the couple had zero probability of
bearing a child with blood group B;
18. Explain how a plant cell is made flaccid. (3mks)
By placing a plant cell in hypertonic solution; the cell will lose water by osmosis; the cell membrane
detaches from the cell wall; and the cytoplasm shrinks;
19. Name the method used by plants to eliminate the following. (3mks)
a) Gum
Exudation;
b) Water droplets
Gullation;
c) Papain
Deposition;
20.
a) Name the response exhibited by maggots. (1mk)
- Negative phototaxis;
b) State the biological importance of the response identified in (a). (1mk)
- Escape predators
- Avoid dehydration/drying up;
21. A student enters a dusty room and immediately develops severe itching and irritation of nasal cavity
followed by sneezing and difficulty in breathing.
d) Name the body reaction caused by dust in the student
- Allergy
e) Explain how the reaction occurs in the body. (2mks)
- Dust recognized by body as antigen triggering production of antibodies; antibody antigen reaction on
the surface of white blood cells release histamine: which causes constriction of bronchiode/ swell of
tissue.
f) State the treatment recommended for the reaction. (1mk)
- Administer anti-histamine drugs;
22. The diagram below represents internal structure of maize gain.
a) Classify the above fruit. (1mk)
- Caryopsis;
b) E- coleptiles;
F-Coleorhiza;
23. a) Name a feature in human lungs which
i) Provide large surface are for gaseous exchange. (1mk)
- Numerous alveoli
Page | 317
ii) Aid faster diffusion of gasses. (1mk)
- Thin epithelium/moist surface;
b) Suggest why asthma patients experience difficulty in breathing. (1mk)
- Blockage of bronchiole/bronchi/alveoli by muscles;
- Reduction of bronchiole lumen;
24.
a) Name the pathogen that was abundant in his system during infection. (1mk)
Mycobacterium tuberculosis;
b) Account for the results for the send test. (2mks)
- Some bacteria resisted the drug and developed mutant gene; which was transmitted to subsequent
generation that replicated rapidly;
25. Explain the condition under which each of the organs in human reproduction system. Show great
increase in size. (2mks)
a) Uterus
- During pregnancy elastic muscles on the walls of uterus relax; to accommodate growing embryo;
b) Penis
- During sexual excitement; spaces in loose connective tissue fill with blood making penis rigid;
26. Describe the role of antidiuretic hormone in selective reabsorption when potential of the body fluids
rises above optimum. (3mks)
- ADH reduces permeability of the kidney tissue to water; tubule reabsorption of water from the
glomerular filtrate back into blood stream by osmosis; thus restoring osmotic pressure to normal.
27. Explain how the following parts of light microscope contribute to the formation of image of the
specimen.
a) Condenser. (1mk)
- Concentrates light passing through the diaphragm to the specimen on the stage for illumination;
b) Mirror (1mk)
- Reflects light to the specimen on the slide on the stage;
c) Objective lens (1mk)
- Magnifies the specimen.
28. How is mechanical digestion achieved in the following parts of alimentary canal
d) Mouth (1mk)
- Through mastication;
e) Stomach (1mk)
- Through churning;
f) Duodenum (1mk)
- Though emulsification;

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 THE SUPERIOR JET
231/2
BIOLOGY
PAPER 2
MARKING SCHEME
1. a)
Parental phemotypes Roan coat Roan coat
Parental genotypes GH X GH;
Parental gametes ;
;
G H G H
F2 Genotypes

GG GH GH HH
Red Roan White
1GG : 2GH : 1HH;
Acc use of a punnet square

G H

G GG GH
H GH HH
b) Has many contrasting characteristics; Easy to breed in the laboratory;
Do not transmit any human diseases hence safe to handle;
Have short generation time hence many generations can be studied;
Lay many eggs increasing sample size;
Any one correct
c) Useful in identification of defective genes hence their correction;
Useful in identification of genes that are susceptible to certain diseases hence preventive measures;
Production of proteins produced by certain genes hence producing drugs to enhance or inhibit their
activity;
First two
2. a) Increase in breathing rate;
b) i) Lower concentration of oxygen in high altitude area; raises the demand of oxygen by body
cells;
ii) Number of red blood cells has increased hence enough oxygen is reaching all body cells
adequately;
c) Has a higher capacity of transporting oxygen to body cells; due to higher number of red blood
cells in the body;
d) i) Muscle cramps / Muscle fatigue;
ii) It is completely oxidized by oxygen into water, carbon (IV) oxide and energy/ is converted into
glycogen for storage;
3 a) Encloses cell contents;
Allows selective movement of materials in and out of the cell;
b) A- Phospholipid; B- Protein molecule;
c) For faster passage of materials;
d) It will be denatured; because it has protein molecules that are sensitive to temperature above
optimum;

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 e) Enables the membrane to detect changes in the environment;
Affects movement of substances in and out of the membrane; OWTTE
4. a)
i) 4- Urinary bladder; 8 Rectum;
ii) 1- Sit for production of ovum/ ova; Secretes Progesterone & Oestrogen;
7- Secretes a plug of mucus; which prevents entry of pathogens into the uterus during pregnancy;
iii) 2
- Tubular to allow for transportation of the ovum towards the uterus;
- Have goblet cells that secrete mucus to lubricate the epithelium for easier transportation of ovum /
zygote towards the uterus;
- Have smooth circular and longitudinal muscles that contract and relax to allow for propulsion of the
ovum / zygote towards the uterus;
- Ciliated epithelium to propel the ovum / zygote towards the uterus; FIRST TWO.
b) The remains of the Graafian follicle are reorganized to form corpus luteum; the corpus luteum is then
stimulated to start secreting Oestrogen hormone;
5. a) i) Dicotyledonae;
ii)
Region R Region T
Cells strengthened with cellulose Cells strengthened with Lignin;
Cells are spherical Cells are elongated fibres;
Cells are dead Cells are living;
b) (Are straightened from the body) thus increasing the vertical surface area of the fish;( thus
preventing rocking of the body from side to side and lateral deflection of the body)
c) i) Ligament ; Cartilage ; Synovial Fluid; Synovial membrane;
ii) Absorb shock; Lubrication/ Reduce friction;
iii) Limits upward bending of the leg at the knee/ Prevents overstretching of the joint;
6. a)

b)
i) chloride ions
Diffusion; its rate of absorption does not depend on photosynthesis which yields glucose/energy
/ATP;
ii) Nitrate ions
Active transport; its rate of absorption depends on photosynthesis which yields glucose that is
oxidized to release energy;
OWTTE
c) Tied to b) above/ if b) above is wrong then ignore c /don’t award c))
i) 0.2-0.8 units

Page | 320
 The rate of nitrate ions steadily/linearly/rapidly increases with increase in the rate of photosynthesis;
due to continuous formation of glucose; which is oxidized to yield energy (for active uptake of ions);
ii) 1.0-1.8
The rate of uptake of nitrate ions slows down and finally steadies/levels off with further increase in
photosynthesis; due to optimum glucose formation hence optimum rate of oxidation of glucose
which yields constant amount of energy for active uptake;
d) They are easily obtained from the body; with almost no/ minimal pain;
7 Nasal cavity; has cells that produce mucus; has hairs/ cilia that trap and propel dust/microbes to the
pharynx ( to be breathed out); Nasal cavity is supplied with capillaries; that warm the air for faster
flow in the channels; The Epiglotis; covers the trachea during swallowing; so that food particles may
not enter the trachea/ bronchi; Have cartilage rings; to keep the passages open/ prevent them from
collapsing; Lined with mucous membranes which have hairs/ ciliated; to waft out dust particles;
(Lungs) have numerous Alveoli; to increase surface area for gaseous exchange; Alveoli (Alveoli
scores once) have a thin epithelium; to reduce the distance ( through which gases diffuse for easier
and faster); Alveoli are moist; to dissolve oxygen for faster transport; Lungs are spongy; and a
network system of trachea, bronchi and bronchioles; to provide an efficient system/ large surface
area for gaseous exchange; Lungs enclosed in a pleural membrane; which secrete pleural fluid; that
protect the lung surface/ shock absorber; lubricates the chest cavity;
Ribs have intercostals muscles; that contract and relax/ moves allowing for inhalation and
exhalation; and also protects the lungs;
Has Diaphragm muscles; whose contraction and relaxation leads to inhalation and exhalation;
8. a) Distant object
Ciliary muscles relax; creating a tension on suspensory ligaments / suspensory ligaments contract;
the lens become flattened/ less convex ; minimizing the refractive power of the lens; bringing light
rays from a far / distant object to focus on the retina; 5 marks
b)
CAUSES EFFECTS
Industrial effluents; Have heavy metals that poison aquatic organisms;
Oil effluents clog respiratory surfaces of aquatic organisms/ death due
to suffocation;
Untreated organic matter; (Has Phosphates/ Sulphates/Nitrates/Salts/) cause eutrophication;
cause algal bloom depriving the water of nutrients; When the algae
die leads to an increase in putrefying bacteria whose decomposition
leads to the release of awful smells /odours;
Domestic effluents / sewage; Form a habitat of pathogens that spread water borne diseases;
Decomposing sewage promotes eutrophication leading to algal
bloom;
Death promotes / attracts saprophytic bacteria that use up oxygen in
water/ causing suffocation/ death to aquatic organisms;
Agrochemicals/ Fertilizers; Phosphates /Nitrates cause eutrophication;
Heavy metals in agrochemicals affect respiratory surfaces/ cause
breathing problems;
Hot water; Raise temperature of water; killing organisms; dissolves less oxygen
(reducing its content in water);
Oil spillage; From tanks/ refineries soak feathers of marine birds preventing flight;
Clogs respiratory surfaces leading to death;
Coats photosynthetic Phytoplanktons;
Reduces light penetration hampering photosynthesis;
Sediments (from soil Makes water dirty;
erosion); Makes water unfit for consumption;
Clogs respiratory surfaces hindering gaseous exchange;
Reduces light penetration hindering photosynthesis;

Page | 321
NB Causes and effects marked independently/ not tied
Effect is marked / Awarded once
Causes, maximum score 5 marks , Effects, maximum score 5 marks
Control Measures
Enforcements of environmental laws; Use of unleaded fuel/petroleum products; Proper treatment and
disposal of sewage wastes; Treatment of industrial effluents before release; Public education on
correct use of inorganic fertilizers/ agrochemicals; Use of alternative and safe methods for weeds/
pests control/ organic manure; Use of undersea pipelines instead of tankers to transport oil products;
Cooling hot water before release to water bodies;

THE SUPERIOR JET II JOINT EXAMINATION

BIOLOGY
231/3
Paper 3 (Practical)
(a) (i) test tube 1
Vigorous/rapid/fast/a lot of/high/large amount/big
amount/morbubbles/effervescence/frothing/foaming;
test tube 2
Little/small amount/less bubbles/effervescence/frothing/foaming;
ii) tied to (a) (i)
test tube 1
More substrate molecules/large amount of substrate/high concentration of substrate available; for a
large amount enzyme molecules; hence high rate of enzyme reaction;
test tube 2
Less substrate molecules/small amount of substrate/low concentration of substrate available; (for a
small amount of less enzyme molecules) hence low rate of enzyme reaction;
(b) Increase the concentration of the substrate;
Increase temperature towards optimum/provide optimum temperature; Add co-enzymes/co-factors to
the mixture;
(c)
Food substance Procedure Observation Conclusion
Starch To (about 2ml of) the extract/extract Blue-black colour; Starch present;
from the potato add (2 drops of) iodine
solution;
Vitamin C/Ascorbic To (about 2ml of) DCPIP add the Blue colour; Vitamin C absent;
acid extract/ extract from the potato;
Question 2
(a) Photograph A
Positive geotropism;
Photograph B
(Positive) thigmotropism/ Haptotropism;
(b) Photograph A
Gravity; causes auxins to migrate/diffuse to the lower side of the shoot; where they stimulate
rapid/faster growth/cell elongation;
Photograph B
Contact; causes auxins to migrate/diffuse to the opposite side of the shoot/side not in contact; where
they stimulate rapid/faster growth/cell elongation;

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(c) Enables shoots to avoid injuries on the ground; Enables shoots to grow upwards towards light;
(d) Question 3
(a) i) Rib;
ii) Has capitulum; Has tuberculum; Has a curved shaft;
(b) Curved shaft to increase volume in the thoracic cavity; Long/flattened to increase surface area for
attachment of muscles; It is ossified/bony/hard to protect organs in the thoracic cavity;
Has capitulum/tuberculum for articulating with facets on the thoracic vertebra;
(c)
1- Femur;
2- Patella/Knee cap;
3- Tibia;
(d) Provides surface for attachment of muscles/tendons/ligaments;
Prevents overstretching of bones at the knee joint/Limits movement at the knee joint;
(e) i) Synovial;
ii) Lubrication of the joint/Reduces friction at the joint; Rj prevents friction
Absorbs shock;
Nourishment of tissues at the joint;

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 PRACTICE EXERCISES
VIHIGA COUNTY QUAKER JOINT EXAMINATIONS
231/1
BIOLOGY
PAPER 1 (THEORY)
TIME: 2HOURS.
1. What is biochemistry? (1mark)
2. Name two tissues that are thickened with lignin and serve as strengthening tissues in plants.
3. The diagram below shows a longitudinal section of a mammalian skin.

i. Name the parts labeled F and G. (2marks)

ii. State two functions of the secretion from part labeled Y. (2marks)
4. In an experiment on respiration, a mouse was observed to have inhaled 200cm3 of oxygen and
exhaled 199.75cm3 of carbon IV oxide in ten minutes.
i. Calculate the respiratory quotient for the activity in the experiment. (2marks)
ii. suggest the food substrate that was being broken down. (1mark)
5. State three ways of breaking seed dormancy. (3marks)
6. Using a suitable example in human beings, define the term vestigial structures. (2marks)
7. a) Name the causative agent of amoebic dysentry. (1mark)
b). state two ways in which the larval forms of schistosoma are adapted to their parasitic life.
(2marks)
8. Study the flow diagram below and answer the questions that follow.
Trypsinogen compound X Trypsin
i. Name compound X. (1mark)
ii. State the role of enzyme trypsin in the digestion process. (1mark)
9. Study the structure below and answer the questions that follow.

a) Identify the part labeled A. (1mark)

b) State two modifications that adapts the structure to its function. (2marks)
A student observing a leg of an insect under a hand lens made a drawing of the leg whose length was
4cm with a magnification of X2. What was the actual length of the leg? (2marks)
10. Draw a dicotyledonous leaf with a serrated margin. (2marks)
11. Explain what happens to excess amino acids in the liver of humans. (2marks)
12. The figure below represents a plant.

a) Name the division it belongs to. (1mark)

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b) Name the part labeled A. (1mark)
c) What is the function of the part labeled B? (1mark)
13. Explain why plants absorb water in waterlogged soils but not mineral salts. (2marks)
14. What is the significance of;
a) Red blood cells lacking mitochondria. (1mark)
b) Xylem vessels having narrow lumen. (1mark)
15. Most carbon IV oxide is transported from tissues to lungs within the red blood cells and not in blood
plasma. Give two advantages of this mode of transport. (2marks)
16. a) Define the term habitat. (1mark)
b) Why is it important to use dry mass in ecological studies and not wet mass? (2marks)
17. Name the part of a seed that elongates to bring about epigeal germination. (1mark)
18. Explain why it is no longer possible to treat malaria using chloroquine. (3marks)
19. Name the branch of biology that would be used in solving the problem of disputed parentage.
20. The diagram below shows a pollen tube as it develops down the style. Use it to answer the questions
that follow.

a) Name the part labeled G. (1mark)

b) State two functions of the structure labeled E. (2marks)
21. A group of students set up an experiment to investigate a certain physiological process. The set up
was as shown in the diagram below. After sometime, the students observed that the level of the sugar
solution had risen.

a) What physiological process was being investigated? (1mark)

b) Account for the rise in the level of sugar solution in the experiment. (2marks)
c) Suggest the results that the students would obtain if they repeated the experiment using a piece of
boiled pawpaw. (1mark)
22. List three factors in a flower that hinders self-pollination. (3marks)
23. State two reasons why clot formation is important when a blood vessel is cut. (2marks)
24. The diagram below represents a mammalian bone.

a) Name the bone that articulates with the bone drawn above at the posterior end. (1mark)
b) Name the type of joint formed by the bone drawn above at its anterior end. (1mark)
25. The diagram below represents a cross section of a plant.

a) From which part of the plant was the above section obtained? (1mark)

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b) Label A and B. (2marks)
c) State the function of the structure labeled C. (1mark)
26. A man with normal colour vision marries a colour blind woman. Their first four children were
daughters all with normal colour vision. Their two sons were colour blind.
a) On which chromosome is the gene for colour vision located? (1mark)
b) Using a punnet square,work out the possible genotypes of all their children . Use the letter B to
represent the gene for normal colour vision and b to represent the gene for colour blindness.
(4marks)
27. Study the reaction below and answer the questions that follow.

a) What biological processes are represented by A and B? (2marks)

b) Identify the product Y. (1mark)
c) State the bond represented by X. (1mark)
28. State the characteristics of living organisms exhibited by the following;
i. A mango tree producing flowers. (1mark)
ii. A man sneezing. (1mark)
29. A response exhibited by a certain plant tendril is illustrated below.

a) Name the type of response. (1mark)

b) Explain how the response named in (a) above occurs. (2marks)
c) What is the importance of tactic response to microscopic plants. (1mark)
30. Name the genetic disorder characterized by inability of blood to clot. (1mark)

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 VIHIGA COUNTY QUAKER JOINT EXAMINATIONS
231/2
BIOLOGY
PAPER 2 (THEORY)
2 HOURS
1. The following is an illustration of feeding relationship of organisms in a given ecosystem

Owl

shrew Wood mouse

spider

Grasshopper
snail
Beettle
Green plants

a) From the above, write a food chain with: (2mks)

(i) Owl occupying third energy level.
(ii) Owl as quaternary consumer.
b) Why should the green plants have the highest biomass? (2mks)
c) (i) Which organism is lacking for the above to be a complete ecosystem. (1mk)
(ii) What is the role of the organism mentioned in c(i) above. (1mk)
d) A researcher randomly caught 500 grasshoppers, marked them with ink and released them back to
the environment. 24 hours later, he caught 474 out of which 394 lacked the ink, mark. Determine the
population of grasshoppers in that habitat (2mks)
2. The following are steps followed when testing for starch in a leaf

a) Why would it be necessary to do the following:

(i) Place the leaf in sunlight for 5 hours before the experiment. (1mk)
(ii) Dip the leaf in boiling water for 5 minutes. (1mk)
(iii) Place the leaf in boiling Ethanol (1mk)
(iv) Flooding the leaf with iodine solution. (1mk)
b) State the conclusion to be made when the following colours are observed. (2mks)
Observation Conclusion
Brown
Blue - Black

c) State two reasons why plants store carbohydrates as starch and not glucose (2mks)
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3. The following is an illustration of an internal section of the human testis

a) Name the types of cell division that results into formation of:
(i) Cell D from cell B (1mk)
(ii) Cell B from cell E (1mk)
b) Give the name and function of hormone released by the cells labelled A. (2mks)
c) Give two ways cell C is important to the development of the spermatids. (2mks)
d) State the significance of the following:
(i) The human testes are found hanging outside the male body. (1mk)
(ii) One ejaculation during sexual intercourse releases millions of spermatozoa (1mk)
4. The following table shows variations in concentration of forms in which carbon IV oxide is
transported by blood at rest and during physical body exercise.
Form in which carbon oxide is T Rest Mole/litre During Physical body
transported exercise (mole/litre)
Dissolved Carbon IV oxide 0.52 0.97
Hydrogen Carbonate ion 12.34 13.68
Carbon IV oxide bound to a protein 0.26 0.16
Total Carbon IV oxide in plasma 13.12 14.81
pH of Blood 7.42 7.09

a) Give an explanation on how involvement in physical body exercise affect pH of blood (2mks)
b) i) Name the protein in the blood responsible for transport of Carbon IV oxide. (1mk)
ii) Write a word equation for the reaction between carbon IV oxidemolecule named in b(i) above
(1mk)
c) Explain why more carbon IV oxide is transported inform of hydrogen carbonate. (2mks)
d) Why is it that a person sleeping in a poorly ventilated room with a lit charcoal burner is likely to die
by suffocation? (2mks)
5. The diagram below shows samples of blood obtained from two different person A and B.
Photograph A Photograph B

a) What genetic disorder is person B suffering from (1mk)

b) State one Advantage and one disadvantage of the disorder exhibited in person A (2mks)
c). Identify the Genotypes and Phenotypes of offsprings of a marriage between person A and B. Show
your working. (5mks)
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6. In a study, Grace and mercy each drunk juice containing 5 grams of glucose. T intervals of 15
minutes, the concentration of glucose in their blood was measured and tabulated as shown below.
Time in minutes Grace Mercy
Blood Glucose Level (Mg/dL) Blood Glucose Level(Mg/dL)
0 94 100
15 94 100
30 97 160
45 107 205
60 114 245
75 116 265
90 115 266
105 109 254
120 100 233
a) Using the same axes, plot a graph of Blood Glucose level against time for the two students.
(8mks)
a). Account for the shape of graph at:
(i) 0 – 15 minutes. (2mks)
(ii) 30 – 75 minutes (2mks)
b) Determine the concentration of glucose in blood of the two participants at 56th minute.
(i) Grace
(ii) Mercy
c) Describe the role played by pancreas in the drop of blood glucose level observed between 90th and
120th minutes. (4mks)
d) i) Name the likely disorder Mercy is suffering from. (1mk)
ii) State one way in which the disorder mentioned in e(i) above can be managed. (1mk)
7. a) Explain how various components of blood are adapted to their functions. (16mks)
b) Outline the differences between the features of insect pollinated flowers and wind pollinated
flowers. (4mks)
8. a) Describe how the human body restores osmotic pressure of body fluids. (8mks)
b) Describe the opening and closing of stomata using the starch-sugar interconversion theory.
(12mks)

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 VIHIGA COUNTY QUAKER JOINT EXAMINATIONS
231/3
BIOLOGY
PAPER 3 (THEORY)
2 HOURS
CONFIDENTIAL
1. 4 Test tubes on a rack
2. Dilute Egg Albumen
3. Dilute Hydrochloric Acid with a dropper
4. Sodium Hydroxide solution with a dropper
5. Solution P. (Protease)
6. 2 droppers
7. 3, 10ml measuring cylinders
8. Stop watch or a means of timing
9. A water bath maintained at 500C to 600C
10. 3 labels
11. Hibiscus flower (specimen S)

VIHIGA COUNTY QUAKER JOINT EXAMINATIONS

231/3
BIOLOGY
PAPER 3
TIME: 1 ¾ HOURS
1. The following are photographs of specimens, P and Q.
Both of them belong to the same Phylum and class. Observe them carefully before you answer the
questions that follow.

a). i). Name the class to which P and Q belongs and support your answer with two reasons.
Class (1mk).
Reasons (2mks).
ii). Suggest why the transport fluid in P and Q lacks Haemoglobin. (2mks).
b). The actual Length of Specimen Q is 9cm. Given that both P and Q are under the same
Magnification, Determine the Actual Length of P. (3mks)
c). Below is a diagram showing the life cycle of Specimen P.

i). Identify the stage labelled D. (1mk)

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ii). Name the Hormone that is responsible for what happens from Stage D to A. (1mk)
iii). Explain what happens from Stage C2 to C3 and C3 to D (2mks)
iv). State the importance of the process illustrated above in the life cycle of organisms (2mks)
2. You have been provided with materials and reagents on your working benches.
Procedure:
i). Label Test tubes A, B, and C.
ii). Put 2ml of Egg Albumen into each of the Test tubes A, B and C.
iii). Add 1ml of Solution P in each of the Test tubes.
iv). Into Test tube A, add 2 drops of Sodium Hydroxide solution
v). Into Test tube B, add2 drops of Hydrochloric Acid
vI). Into Test tube C, add 2 drops of water.
vii). Place all the three test tubes in the water bath for 10 minutes.
a). I). State the observations made in Test tubes A and B (2mks).
II). Account for the observations made in:
Test tube A (3mks)
Test tube B (3mks)
b). Explain why the investigation was carried out at a specific Temperature range. (1mk)
c). State the purpose of Test tube C (1mk).
d). i). With a reason, identify Solution P. (2mks)
ii). Name the Likely part of the Alimentary canal where the Process in the Experiment occurs
iii). Give a reason for your answer in d(ii) above (1mk)
3.(a). Examine PhotographRand specimen S carefully and answer the questions that follow. S2 was
extracted from S1.

i). What name is given to the coiled part labelled T. (1mk).

ii) Name:
the type of response exhibited by the coiled part on Specimen R. (1mk).
iii). Stimulus responsible for the response named in (ii) above (1mk).
iv). Explain how the response exhibited by the coiled part on Specimen R occurred. (3mks).
v). State the biological significance of the Response described in (iv) above to the survival of the
Specimen. (1mk).
b) Use the specimen labelled S to answer the following questions.
(i) State the agent of pollination for the specimen (1mk)
(ii) Give a reason for your answer (1mk)
(iii) Describe the external features of Androecim and Gynoecium of specimen S. (2mks)
(iv) What are the adaptations of pollen grains obtained from specimen S. (1mk)

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 A.C.K DIOCESE OF MUMIAS JOINT EVALUATION
231/1
BIOLOGY
(THEORY)
Paper 1
1. Identify the apparatus represented by the diagram below and states its function,

(i) Name (1 mark)

(ii) Function (1mark)
2. i) With reference to circulatory system only give two reasons why birds and mammals are more
active compared to other organisms? (2marks)
ii) State two differences between open circulatory system and closed circulatory system (2 marks)
3. Explain why a pregnant woman excretes less urea compared to a woman who is non- pregnant.
4. a. State two features of the placenta which speeds up the exchange of materials between the mother and
the foetus. (2marks)
b. Name the two hormones involved in regulation of the menstruation cycle. (2marks)
5. State the role of the liver in each of the following processes
(a) Digestion (1mark)
(b) Excretion (1mark)
6. (a) State one way in which human body is naturally protected against harmful bacteria. (1mark)
(b) State two ways in which the composition of blood in the pulmonary artery and that of
pulmonary vein differ. (2marks)
7. Construct a possible food chain for the crocodile, fish algae and mosquito larvae found in an aquatic
ecosystem (2marks)
8. Plants relatively have less waste to excrete than animals. Give two reasons to explain this
observation. (2marks)
9. A strand of a DNA molecule was found to have the following base sequence.
C -G -A -T -G –T
(a) What is the sequence on m–RNA strand copied from this DNA portion? (1mark)
(b) Write the Complementary DNA strand from the above DNA portion (1mark)
(c) State two roles of DNA molecule. (2 marks)
10. a) Name the gaseous exchange structure in woody stems. (1mark)
(b) State two adaptations of xylem vessels their functions (2marks)
11. Name the type of carbohydrates (polysaccharides) found in the following parts of living
Organisms. (3 marks)
(i) In the exoskeleton of arthropods (ii) In the xylem vessels (iii) In the animals blood
12. In an experiment to observe some variation in length of leaves, the following curve was obtained.

(a) Identify the type of variation illustrated by the curve. (1mark)

(b) State two meiotic processes that cause variations (2marks)
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13. The diagram below represents a chloroplast.

a) Name the parts labeled M and L.

b) Describe the process that takes place in the structure labeled K. (3marks)
14. a) Name the other transport system in animals other than blood circulation system. (1 mark)
b) Distinguish between natural acquired artificial immunity and acquired immunity.(2marks)
15. The diagram below represents a transverse section through a plant organ. Study it and
answer the questions that follow.

(a) From which plant organ was the section obtained. (1 mark)
(b) Name the parts labeled Q, N and P. (3 marks)
16. The diagram below shows gaseous exchange in mammalian tissues.

(a) Name the gas that diffuses;

i) To the body cells (1mark)
ii) From body cells (1mark)
(b) Which compound dissociates to release the gas named in (a) (i) above (1mark)
17. State two classes of the phylum Chordata where all members are endothermic. (2 marks)
18. Give three adaptations of animals dispersed fruits and seeds. (3 marks)
19. An experiment was set up as shown below. Study it and answer the questions that follow
i) The set up was left for 20 minutes. State the expected results. (1 mark)
ii) Explain your answer in (i) above. (2marks)
20. (a) What is the role of antidiuretic hormone in osmoregulation? (1mark)
(b) Explain why under normal circumstances, glucose is absent in urine yet it is present in the
glomerular filtrate. (2marks)
21. Explain what happens in humans when the concentration of glucose in the blood rises above the
normal level. (3marks)

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22. The diagram below shows a type of epithelial tissue.

(a) Name the hair- like structures. (1mark)

(b) What is the function of the hair – like structures? (1mark)
(c) Name two mammalian organs where this type of epithelium is found. (2marks)
23. In what ways are the gill filaments of a fish adapted to their function? (2 marks)
24. Below is a diagram of a specialized plant cell.

(a) Identifying the specialized cell (1mark)

(b) State the function of each of the following cell organelles
(i) Golgi bodies (1mark)
(ii) Lysosomes (1mark)
25. Explain how fossil records serves as evidence for evolution. (2 marks)
26. (a) Name an organ in which meiosis occurs in : (1mark)
(i) A flowering plant
(ii) A mammal. (1mark)
(b) (i) Name the stage of meiosis during which sister chromatids separate (1mark)
(ii) What is the importance of crossing over in living organism? (1mark)
27. Explain the effects of the following on the quantity and composition of urine.
(a) Drinking large amount of clean water (1mark)
(b) Removal of pancreas (1mark)

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 A.C.K DIOCESE OF MUMIAS JOINT EVALUATION
BIOLOGY
PAPER 2
231/2
TIME: 2 HOURS
SECTION A: (40 Marks)
1. Below is a diagram of a mammalian skin, use it to answer the questions that follow.

a) Name the parts labelled P, Q, R (3mks)

b) Give the function of the parts labelled Q and T. (2mks)
c) Briefly explain how the part labelled R contribute to lowering of body temperature on a hot day.
(2mks)
d) Give one function of the mammalian skin other than thermoregulation. (1mk)
2. Red-green colour blindness is controlled by a sex-linked gene. The allele for normal sight is
represented by letter C and of colour blindness is represented by letter c. A carrier female is
married to a colour-blind male.
a) What is sex linked gene? (1mk)
b) Write down the genotype of the parents. (2mks)
c) Work out the F1 genotypes. (4mks)
d) What is the percentage of colour-blind sons in all the male offspring’s? (1mk)
3. Study the diagram below and answer the questions that follows

(a) What type of evolution is illustrated by the limbs (1mk)

(b) What does the origin of the limbs suggest about the ancestry of these animals. (1mk)
(c) (i) What are vestigial structures? (1mk)
(ii) State an example of vestigial structure in humans. (1mk )
(d) (i) What is natural selection? (2mks)
(ii) Give one example of nature selection in action. (1mk)
(e) Explain comparative serology as evidence of evolution. (1mk)

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4. The diagram below shows the site where exchange of substances takes place in the mammalian
circulation.

a) Name the vessels labelled S and T (2marks)

b) Name the fluid labelled F and state its importance. (2marks)
c) Name the :
i) Respiratory substances that move out of the capillaries (1mark)
Respiratory end products that are removed from tissue cells. (1mark)
d) Name the blood cells that may be found in the fluid labelled F. (1mark)
e) Name components of blood that are not found in the fluid labelled F. (1mark)
5. a) Describe the process of inhalation in mammals (4mrks)
b) Explain two ways in which the following structure are adapted to gaseous exchange.
i) Mesophyte leaf
ii) Pneumatophores
SECTION B: (40 MARKS)
6. The data below represents the level of progesterone hormone produced in a female’s body within a
period of 34 days. Study the data and use it to answer the questions that follow.
N/B: The days were counted from the 1st day that menstruation was noticed.
Day Progesterone hormone concentration in arbitrary units
1 6
2 5
3 3
4 2
5 1
6 1
8 1
10 2
12 4
14 7
16 8
20 9
22 10
24 10
26 10
28 10
30 11
32 11
34 11
a) Plot a graph of progesterone concentration against time using a suitable scale. (7mrks)
b) Account for the progesterone levels in the blood stream between
i) Day 1 - day 5 (2mrks)
ii) Day 14 - day 20 (2 mks)
iii) Day 28 - day 35 . (2mrks)
c) Name two structures that produce progesterone in females (2mrks)

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d) Suggest the process that usually takes place at day 14 (1mrk)
e) Suggest two other hormones that were in high concentration in the body of the female between days
11 -- 15. Give reasons for your answer. (4mrks)
7 (a) Explain how the human ileum is adapted to its function. (10mks
(b) Explain the role of the liver in regulation of blood sugar. (10mks).
8 a) Explain the economic importance of fungi. (8mks)
b) Describe the adaptations of flowers to insect pollination. (12mks)

A.C.K DIOCESE OF MUMIAS JOINT EVALUATION

BIOLOGY
PRACTICAL 231/3
CONFIDENTIAL
EACH STUDENT WOULD REQUIRE:
1. HALF PIECE OF SPECIMEN M TRANSVERSELY CUT
2. A TEST TUBES
3. 50ML BEAKER
ACCESS TO:
1. DICHLOROPHENOL INDOPHENOL (DCPIP) SOLUTION
2. SPECIMEN O – ATLAS VERTEBRAE
3. SPECIMEN P –CERVICAL VERTEBRAE
4. MEANS OF CUTTING
5. TEA FIELTERSTRAINER

A.C.K DIOCESE OF MUMIAS JOINT EVALUATION

231/3
BIOLOGY
PAPER 3
TIME:1 ¾ HOURS
1) You are provided with specimen M.
a) i) Identify the part of the plant from which the specimen was obtained. (1mk)
ii) Give a reason to your answer in a) (i) above. (1mk)
b) Name the hormone that causes specimen M to ripen. (1mk)
c) Cut specimen M into two halves. Squeeze the juice from the two halve into a beaker. Filter the juice
and discard the residue. Using the reargent provided test for the food substance in the juice. fill the
table below. (4mks)
d) Photograph H 1 shows specimen H 1 obtained after germination of a seed from specimen M. study it
and answer the question that follow.

photograph H 1

(a) Identify the type of germination exhibited by specimen H. (1mk)

(b) Give areason for your answer in d (a) above. (1mk)
(c) Identify and label on the diagram the name of the curved part. (1mk)

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e) Name the deficiency disease in humans that may result from lack of the food substance found in (c)
above. (1mk)
f) State the type of placentation in specimen M. (1mk)
g) i) State the mode of dispersal for specimen M. (1mk)
ii) How is specimen M adapted to the mode of dispersal stated in g. (i) above. (2mks)
2) The photograph below shows a dissection of a rabbit displaying urinary and reproductive system.

a) On the diagram label the following parts (4mks).

Adrenal gland
Prostate gland
Epididymis
Vas deferens.
b) State the functions of the parts you have labeled on the diagram.
b) state the homeostatic function of kidney. (1mks)
c) i) state the function of ureter. (1mk)
ii) why do testis hang outside the body. (1mk)
3) you are provided with specimen O and P. You are also provided with photograph Q1 and R1. study
them and answer the questions that follow.
photograph Q 1

photograph R 1

a) Identify specimen O, P, Q1 and R1. (4mks)

b) Draw the dorsal view of specimen O. label on the drawing the vertebraterial canal. (2mks)
c) Identify and label the following parts on photograph on specimen Q. (3mks)
obturator foramen
Acetabellum
Pupis symphysis
d) which bone articulates with specimen R on the posterior end. (1mk)
e) Identify and give two charecterestics of the bone that articulates with specimen O on the posterior
end.

Page | 338
 MUMIAS WEST JOINT EVALUATION FORM FOUR
231/1
BIOLOGY
THEORY PAPER 1
TIME: 2 HRS
1. Name the organelle that:
a) Manufactures and transports lipids and steroids in a cell (1mark)
b) Contains enzymes that are capable of destroying old damaged cells. (1mark)
c) Controls all the processes in a cell. (1mark)
d) Forms Cilia and flagella in cells that have them (1mark)
2. The diagram below represents an experimental set up. The set up was left for two hours.
The level of the solution in the funnel increased while the red dye was seen in the beaker.

Water Beaker

Concentrated Nacl in Red dye

Pig’s bladder

a). Identify the process that led to:

i. Increase in the solution level in the funnel. (l mark)
ii. Appearance of red dye in the beaker. (l mark)
b). State the role of the pig’s bladder. (l mark)
c). What is the role of the process named in (a)( i) above in plant nutrition (1 mark)
3. State two structural differences between phloem and xylem tissues. (2marks)
4. It was found that during germination of bean seeds, 9.2 cm3 of carbon IV Oxide was produced while
9.0 cm3 of oxygen was used up.
a) (i) Calculate the respiratory quotient of the reaction:- (2 marks)
(ii) Identify the substrate being metabolized. (1mark)
b) In which part of the cell does glycolysis occur? (1 mark)
5. The experiment illustrated below was set up to investigate a certain physiological process using a
raw potato tuber

Concentrated glucose
solution
Raw potato tuber
Trough

Distilled
water

(a) Suggest a possible physiological process that was being investigated. (1 mark)
(b) Explain the results obtained in the above experiment after a few hours (2 marks)
(c) State the observations that would have been made if the experiment was repeated using boiled
potato. (1 marks)

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6. State two roles of luteinising hormones in female reproduction. (2mks)
7. The diagram below shows a cross section of a plant stem.
X

Y
Z

i) State the class of the plant from which the organ was obtained (1 mark)
ii) Name the parts labeled X Y and Z (3 marks)
8. What are the causative agents for the following sexually transmitted diseases? (2marks)
i) Gonorrhea
ii) Syphilis
9. (a) What is meant by the following terms as used in ecology : (2mks)
i) Population
ii) Carrying capacity
b) During an ecological visit to Maasai Mara students were able to see antelopes, lions, vultures, and
pastoralists grazing their cattle. Construct a food chain with four consumer levels ending with the
vulture to illustrate the energy flow in the ecosystem. (2mks)
10. The graph below shows the effect of substrate concentration on the rate of enzyme reaction.

(a) Account for the shape of the graph between A and B (2marks)
(b) How can the rate of reaction be increased after point B? (1mark)
(c) State one other factor that affects the rate of enzyme reaction. (1mark)
11. The diagram below shows stage during cell division.

(i) Identify the stage of cell division in the diagram above (1 mark)
(ii) Give a reason for your answer in (i) above (1mark)
(b) How are the spongy mesophyll cells adapted to their functions? (1mark)
12. Differentiate between the following terms:- (2mks)
(i) Hypogynous flower and epigenous flower
(ii) Gamopetalous corolla and polypetalous corolla
13. a) State one event that occurs in the prophase of meiosis I which does not occur in prophase of
mitosis. (1mark)
b) What are the results of the above phenomenon? (2 marks)
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14. What is the importance of seed dispersal? (2 marks)
15. The diagram shown below represents a flower

a) Name the agent of pollination for the flower shown above (1mark)
b) Give TWO reasons for your answer in a) above (2 marks)
16. State one economic importance of the following plant products. (2 marks)
a) Papain
b) Caffeine
17. A particular food substance is suspected to contain vitamin C.
(a) Name the chemical that would be used to confirm presence of vitamin C. (1mk)
(b) What are expected results if vitamin C was present? (1mark)
18. Give two reasons why nutrition is important to living animals (2 marks)
19. State the role of the following substances present in saliva during food digestion
(i) Mucus (3 marks)
(ii) Water
(iii) Amylase
20. Evolution is an ongoing process and is still going on even today. State two pieces of evidence which
suggests that evolution is still taking place. (2marks)
21. The figure below represent the tip of a root.

R1
T
(a) What is the role of the structure labelled T? (1 mark)
(b) Outline two characteristics of cells found in region R1 (2 marks)
22. The following diagrams represent examples of a chromosomal mutation.
A
A

A A
B
B
Y
B X B
C
C C

C
D D
E

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 (a) Name the types of chromosomal mutations represented by X and Y. (2 marks)
(b) What is non – disjunction? (1 mark)
23. Give reasons for the following:
a) A Rhesus negative (Rh-ve) recipient should not receive Rhesus positive (Rh+ve) blood within two
weeks of a similar transfusion. (2 marks)
b) People with blood group AB are considered universal recipients (2 marks)
24. Desert kangaroo rats spend most of their time in underground burrows
a) Name this type of behavioural activity 1 mark
b) Explain the significance of this behavior to the organism (2marks)
25. a)Define the term analogous structures (1 mark)
b) Give two illustrations of analogous structure in mammals (2 marks)
26. Explain why;
a) Mammalian testes are located to hang outside the body. (2marks)
b) Four months after fertilization ovaries can be removed from a human female without
terminating the pregnancy. (2marks)
27. a) State two ideas proposed by Lamark’s in his theory of evolution. (2marks)
b) Why is Lamark’s theory not acceptable? (1mark)

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 MUMIAS WEST JOINT EXAMINATION
THEORY
PAPER 2
2 HOURS
SECTION A (40 MARKS)
Answer all questions in the spaces provided.
1. How are the following structures of a leaf adapted to their function?
(a) Petiole (2mks)
(b) Veins (2mks)
(c) Palisade mesophyl (2mks)
(d) Guard cells (2mks)
2. Study the pedigree chart below showing the inheritance of the allele responsible for haemophilia in a
certain family.

Parents

Key
Normalfemale
Normal male
Haemophiliae male
Offsprings

a) Write down the parental genotypes (2mks)

Father ___________________________________________________________________
Mother __________________________________________________________________
b) Suppose one of the daughters in the pedigree with the same genotype as the mother marries a
haemphiliae male, what would be the phenotypic ratio of normal children to haemphiliac children.
Show your working. (5mks)
c) Name the type of gene mutation that causes the disorder above. (1mk)
3. The population of fish in a pond was estimated using capture – recapture method
a) What equipment was used. (1mk)
b) Describe the procedure used in the experiment (5mks)
c) State the formular for calculating the total population of fish in the pond. (2mks)
4. Study the flow chart below of a process that takes place in both plants and animals

C6H12O6

enzyme controlled chemical reaction X

Pyruvic acid

enzyme controlled reactions in organelle Y of the cell in

absence of oxygen.

Product Z in both plants and animals

(a) Name the above process (1mk)

(b) (i) In the above process name the chemical reaction represented by X. (1mk)
(ii) Name the part of the cell where the enzyme controlled reactions in b (i) above takes place.
(1mk)
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(c) Name the product Z in (i) Plants (1mk)
(ii) Animals (1mk)
(d) What would be the fate of pyruvic acid if oxygen supply is availed in the mitochondria of an animal
cell. (2mks)
(e) What is meant by the term oxygen debt. (2mks)
5. a)
i) State two reasons why clot formation is important when a blood vessel is cut. (2mks)
ii) Explain what happens if a clot forms in a blood vessel in the head. (2mks)
b) State two components of the diet that are needed in blood clotting. (2mks)
c) Name two proteins that are involved in clot formation. (2mks)

SECTION B (40 MARKS)

Answer question 6 compulsory in the spaces provided after each question and either question 7
or 8 in the spaces provided after question 8.
6. Two sets of pea seeds were germinated. Set A was placed in normal day light condition in the
laboratory while set B was placed in a dark cupboard. After a few days, shoots lengths were
measured twice daily and their mean lengths recorded as in the table below
Time in hours 0 12 24 36 48 60 72 84
Set A – length (mm) 12 14 20 23 28 31 47 54
Set B – lengths (mm) 17 23 28 35 48 62 80 94

Using the same axes, plot graphs to show length in millimeters of set A and set B against time.
b) From the graph state the mean shoot length of each set of seedlings at the 66th hour. (2mks)
c) Account for the differences between curve B and A (3mks)
d) Explain what would happen to set B of the seedlings if they were allowed to grow under conditions
of darkness. (4mks)
(f) State three external conditions which must be constant for both set ups. (3mks)
7. Explain how various activities of man have caused pollution of air. (20mks)
8. Explain how abiotic factors affect plants distribution and population. (20mks)

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 MUMIAS WEST JOINT EVALUATION EXAMINATION.
BIOLOGY
PRACTICAL
231/3
CONFIDENTIAL
Each student would require:
1. 8ml of solution q with adropper
2. 3ml of solution z with adropper
3. Test tube rag
4. Test tube holder
5. 10 ml measuring cylinder
6. 4 test tubes
7. 2 labels
8. Specimen o
9. Stop watch
Access to:
• Solution y with adropper
• 1% copper ii sulphate solution with adropper
• 10% sodium hydroxide solution with adropper
• Water bath maintained at acertain temperature
• Thermometer
Note:
• Solution q – egg albumen
• Solution y – 1m hydrochloric acid
• Solution z – pepsin enzyme
• Specimen o – maize seedling grown for two weeks

MUMIAS WEST JOINT EVALUATION EXAMINATION

231/3
BIOLOGY
PAPER 3
TIME:1 ¾ HOURS
1. a) You are provided with solution Q. Carry out a food test to test for the food substance in
solution Q using the reagents provided and fill the table below.
Food substance procedure observation conclusion

b) Place 2ml of solution Q into attest tube. Add four drops of solution Y and shake to mix. Add 1ml of
solution Z to form solution Q1. Label the test tube Q1. Put test tube Q1 into a water bath maintained
at 37 degrees celcius for 20 minutes. Carry out a food test to test for the food substance in solution
Q1 using the reagents provided.
Food substance procedure observation conclusion

c) Place 2ml of solution Q into a test tube. Label the test tube Q2. Add four drops of solution Y into Q2
and shake to mix. Put 1ml of solution Z into another test tube and heat solution Z untill it boils. Add
solution Z (boiled) into test tube Q2 to form solution Q2. Put test tube Q2 in a water bath
maintained at 37 degrees Celsius for 20 minutes. Carry out a food test to test for the food substance
in solution Q2 using the reagents provided.
Food substance procedure observation conclusion

d) what was the aim of the above experiment. (1mk)

e) State the role of experiment 1 (c) above. (1mk)

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f) Suggest the identity of substance Y and state its role.
2. The following photographs shows specimen N in photograph N and specimen M in photograph M.
Study them and answer the questions that follow.
Photograph N Photograph M

a) Specimen N regulates its temperature on a hot day by lying under a rock as shown in photograph N.
(i) What name is given to animals like specimen N whose temperature changes with that of its
surrounding. (1mk)
(ii) Explain the mechanism by which specimen N in the photograph N regulates its temperature.
(iii) Name three mechanism of temperature regulation that occur in specimen M but not in specimen N.
b) i) Name the apparatus that would be used in collection of specimen M. (1mk)
ii) Name the method that can be used to estimate the population of specimen M in a marked area.
iii) Apart from the method named in b (ii) name two other methods of estimating population.
c) i) Observe specimen N, M and O then use them to construct a food chain to show the flow of
energy in an ecosystem. (1mk)

ii) Name the trophic level represented by specimen M. (1mk)

3. The following photograph shows specimen X obtained from specimen O. Study it and answer the
questions that follow.

a) (i) identify the part of the plant from which specimen X was obtained. (1mk)
(ii) Give a reasons to your answer in a (i) above. (1mk)
(iii) During preparation of temporary slide, we have two types of section planes that can be made
of a specimen. Identify the section made of specimen X. (1mk)
(iv) Draw a plan diagram of specimen X and label the parts. (3mks)
b) The following photograph show specimen A obtained from specimen O and specimen B obtained
from M. study them and answer the questions that follow.
Specimen A Specimen B

(i) Name the tissues from which specimen A and specimen B were obtained and give a reason to your
answer. (4mks)
(ii) Identify two cells in photograph B. (2mks)
(iii) State the functions of the cells identified in b (ii) above. (2mks)
(iv) Identify and label on specimen A, two stuctures involved in gaseous exchange. (2mks)

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 KAPSABET
231/1
BIOLOGY
PAPER 1
1. Name the branch of biology that involves the study of:
(a) Organism for the sake of classifying them (1mark)
(b) Microscopic organisms. (1 mark)
2. The diagram below represents a plant

(a) Name the division to which the plant belongs (1 mark)

(b). Give three reasons for your answer in (a) above (3 marks)
3. A student estimating a cell of an onion epidermal cell observed the following on themicroscope field
of view using a transparent ruler.

The student identifies 20 cells across the field of view. Calculate the size of the cell in micrometres.
(3 marks)
4. State the functions of centrioles in a cell. (2 marks)
5. Study the flow diagram below

Name the substance U, V and W. (3 marks)

6. (a). State the deficiency diseases of each of the following vitamins. (3 marks)
(i). B1
(ii). B2
(iii). B6
(b). What is the role of roughage in a diet? (1 mark)
7. State two differences between osmosis and Active transport. (2 marks)
8. In a certain experiment, the following observation was made:
When red blood cell was placed in certain solution, the solution exerted more osmoticpressure

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 leading to cell losing water molecules to become (crenated/shrunk)
(a). What type of solution was the cell placed in respect to the cell’s cytoplasms? (1 mark)
(b). By which physiological process did the cell lose water molecules? (1 mark)
(c). Name two substances that make a cell membrane (2 marks)
9. The diagram below represents a transverse section of a plant part. Study it and answer thequestions
that follow.

(a). Name the class in which the plant belongs. (1 mark)

(b). Give a reason for answer (a) above. (1 mark)
(c). State three adaptations for the structure labeled X to their functions. (3 marks)
10. State THREE structural differences between arteries and veins in mammal (3 marks)
11. (a). Why does carboxyhaemoglobin lead to death? (3 marks)
(b). Name two gaseous exchange sites in higlier plants. (2 marks)
12. State the importance of the following features in gaseous exchange
(i) cartilage in the trachea (1 mark)
(ii) Moisture on the surface of the alveoli. (1 marks)
13. The equation below shows an oxidation reaction of flow food substances
5C51H98O6 + 145O2→ 102
CO2 + 98H2O + Energy
(i) (a) Determine respiratory quotient of the Oxidation of the food substance above (3 marks)
(ii) Identify the food substance. (1 mark)
14. (a). A dog weighing 15.2kg requires 216kg while a mouse weighing 50g. Explain. (2 marks)
(b). Under what condition is lactic acid formed in human muscles? (1 mark)
15. Equal amounts of crushed Irish potato were placed in equal volumes of hydrogen peroxide solution
at indicated PH. The volume of the gas produced was measured and recorded as shownin the table
below. (3 marks)

PH 4.0 7.0 9.0

Volume of gas (cm3) 2.7 7.0 9.0
(a). Name the gas that was produced. (1 mark)
(b). Account for the difference in the volume of the gas produced in PH 4.0 and PH 9.0. (3 marks)
(c). Name two components of blood that are not present in the glomerular filtrate. (2 marks)
(16). Define the following terms (2 marks)
(a) Entomology
(b) Sensitivity
(17). Give two examples of continuous variations in humans. (2marks)
(18). (a) State the causative agent of the following diseases (2 marks)
(i). Typhoid
(ii). Pneumonia
(b). State three preventive measures of schistosomiasis in human beings (3 marks)
19. Describe capture-recapture method of estimating population. (3 marks)
20. State three advantages of asexual reproduction in organisms. (3 marks)
21. The diagram below shows a phenomenon which occurs during cell division.
(a). Identify the stage of cell division in which the phenomenon occurs. (1 mark)
(b). State the importance of phenomenon taking place in the part labelled B. (2 marks)
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22. Name the region in plants where the following take place

(a). Primary growth (1 mark)

(b). Secondary growth (1 mark)
23. State three parameters that can be used to estimate growth in seedlings. (3 marks)
24. State three reasons for classifying organism (3 marks)
25. The diagram below represents a transverse section of an ovary from certain flower.

(i) Name the structure labeled W. (1 mark)

(ii). Name the type of placentation illustrated in this diagram. (1 mark)

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 KAPSABET
231/2
BIOLOGY
PAPER 2
SECTION A – (40 MARKS)
Answer All Questions In This Section In The Spaces Provided.
1. The set up below was used to investigate a certain process.

Glucose solution was boiled and olive oil added on top. It was then allowed to cool before theyeast
suspension was added.
a) Name the biological process being investigated. (1 mark)
b) Why was the glucose solution boiled? (1 mark)
c) What is the importance of cooling the glucose solution before adding the yeast? (1 mark)
d) What is the role of olive oil in the experiment? (1 mark)
e) What will be observed in the lime water at the end of the experiment? (1 mark)
f) Suggest what would be observed if a thermometer reading 250C was inserted in theglucose solution
with the yeast suspension (2 marks)
g) Suggest a control experiment for this set up. (1 mark)
2. In maize the gene for Green colour is dominant to the gene for white colour. A purebreeding maize
plant with green grains was crossed with heterozygous plant.
a) (i) Using letter G to represent the gene for green colour, work out the genotypic ratioof the
offspring. (5 marks)
(ii) State the phenotype of the offspring. (1 mark)
b) What is genetic engineering? (1 mark)
c) What is meant by hybrid vigour? (1 mark)
3. (a) Briefly discuss how the following gives evidences on specification:
(i) Cell biology (2 marks)
(ii) Comparative embryology (2 marks)
(b) State one limitation of using fossil records as an evidence of organic evolution. (1 mark)
(c) (i) What is meant by the term vestigial structure. (1 mark)
(ii) Name two examples of vestigial structures in man. (2 marks)
4. The diagram below shows a tissue in a plant.

a) (i) Identify the tissue shown in the diagram above. (1 mark)

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(ii) State the function of the tissue shown above. (1 mark)
b) State two functions of the part labeled A. (2 marks)
c) Name the two compounds or substances transported by the tissue from the leaf to otherparts of the
plant. (2 marks)
d) Explain the role of xylem in plant nutrition. (2 marks)
5. The results in the table below shows the effects of some conditions on seed germination. Ineach
experiment, all other environmental conditions were kept constant except for the one being
investigated.
Experiment Treatment %
Germination
I Seeds placed in a tightly closed container with pyrogallicacid. 0
II (i) Seeds kept in source of light. 96
(ii) Seeds kept in dark cupboard. 97
III (i) Seeds kept in refrigerator 40C. 0.5
(ii) Seeds kept in oven 600C.(iii)Seeds kept at 350C. 0
92
IV Dry seeds in closed container. Moist seeds in a closed container. 0
87
a) (i) What was the purpose of pyrogallic acid in experiment (i) (1 mark)
(ii) State the aim of the experiment (ii) (1 mark)
b) (i) Account for the results obtained in experiment set-up (iii) (3 marks)
(ii) State why 100% germination was not achieved in experiment (ii) and (iv). (1 mark)
c) Of what biological significance is the condition necessary for germination been investigated by
experiment (iv)? (2 marks)
SECTION B – 40 MARKS
6. (a) An experiment was carried out to investigate the population of a certain micro- organism. Two
petri dishes were used. Into the petri dish labeled M 30cm3 of a culture medium was placed while
30cm3 of the same culture was placed in petri dish labeled N. Equal numbers of micro-organisms
were introduced in both petri dishes. The set-ups were then incubated at 350C. The number of micro-
organisms in each petri dish were determinedat equal intervals for a period of 60 hours. The results
were as shown in the table below.

a) (i) On the same axes draw the graphs of relative number of micro-organisms against time onthe grid
Relative number ofmicro- M 40 40 180 280 1200 1720 1600 1840 1560 600
organisms N 40 40 120 200 680 560 560 600 600 400
Time in hours 0 5 10 7. 23 30 35 42 45 60
provided.
(ii) After how many hours was the difference between the two populations greatest? (1 mark)
(iii) Work out the difference between the two populations at 50 hours (2 marks)
(iv) With a reason state the effect on the population of micro-organisms in petri dish M if the temperature
was raised to 600C after 20 hours (2 marks)
(v) Account for the shape of the curve for population in petri dish N between 46 and 59 hours
b) Explain how the osmotic pressure in the human blood is maintained at normal level (5 marks)
7. (a) Describe how budding takes place in yeast (5 marks)
(b) Discuss the economic importance of bacteria (10 marks)
(c) Describe the methods of excretion in plants (5 marks)
8. (a) Describe the process of photosynthesis in green plant (10 marks)
(b) Explain the various conditions necessary for germination (10 marks)

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 KAPSABET
231/3
BIOLOGY
PRACTICAL CONFIDENTIAL
Each Candidate Requires The Following:
1. About 5g(small)piece of specimen Y.
2. 4 test tubes in a test tube rack and 2 droppers.
3. 10ml of 20% hydrogen peroxide solution in a test tube.
4. 100ml empty beaker – 2.
5. 10ml measuring cylinder.
6. A pair of forceps.
7. Access to hot water maintained at 80°C from a hot water bath.
8. 2 wooden splints.
9. (1 ripe orange fruit labeled specimen K).
10. Scalpel.
11. Access to:
(i) Sodium hydroxide solution - 4ml per candidate.
(ii) Copper (II) sulphate solution - 2ml per candidate.(iii)Dilute hydrochloric acid - 2ml per candidate.
(iv) Sodium hydrogen carbonate solution - 2ml per candidate.
(v) Benedict's solution - 4ml per candidate.(vi)Source of heat.
Note:
• 5g (small) piece of fresh liver labeled as specimen Y.
• 1 ripe orange fruit labeled specimen K.

KAPSABET
231/3
BIOLOGY
PAPER 3
1. You are provided with specimen K. Use it to answer the questions that follow.
(i) Cut a traverse section of specimen K and draw a well labeled diagram of the cut surface.
(ii) State the type of placentation of specimen K (1 mark)
(iii) Apart from the placentation named in (ii), name two other form of placentation.
(iv) Squeeze out the juice from one of the halves of the specimen K and put it in a beaker.
Using the reagents provided, carry out test to identify the food substances present in thejuice.
2. The diagram represents organisms in a certain habitat.

a) State two observable characteristics of living things displayed by the organisms. (2 marks)

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b) (i) Name the respiratory surface used by the organism. (1 mark)
(ii) State three adaptations of the respiratory surface named in (b) (i) above. (3 marks)
c) The organism is found in Kingdom Animalia. Giving two external features, identify thephylum to
which it belong.
d) By use of arrows, show the life cycle of this organism. (1 mark)
e) Complete the table shown below on the hormones, site of production and the functionsplayed by
these hormones in metamorphosis. (3 marks)

Name of Hormone Site of Production Function of the Hormone

……………………… Corpus allatum Formation of larval cuticle
Ecdysone ………………… ……………………………
3. You are provided with the following:
• specimen Y
• Hydrogen peroxide
• 2 test tubes in a test tube rack.
• 2 labels
• 10ml measuring cylinder.
• A scalpel.
• 2 wooden splints.
• 100ml beaker.
Procedure
(i) Label two test tubes A and B.
(ii) Measure 2cm3 of hydrogen peroxide and put in test tube A. Repeat the same procedurefor test tube
B.
(iii) Cut a small piece of specimen Y to two smaller pieces using a scalpel. Place one of the pieces in test
tube A and retain the other piece for the subsequent procedure for test tubeB.
(iv) Immediately, introduce a glowing splint into the mouth of the test tube. Record yourobservations in
the table below.
(v) Put the other piece of specimen Y in an empty 100ml beaker then add 50ml boiling waterfrom a hot
water bath maintained at 800C. Leave the set up for 5 minutes
(vi) Remove specimen Y from the boiling water using a pair of forceps and place in test tube
B. Immediately, introduce a glowing splint at the mouth of the test tube. Record yourobservations in
the table below.
a) Record your observations in this table (5 marks)
b) Explain your answers in (a) above.
(i) A (3 marks)
(ii) B (1 mark)
c) State the role of experimental set up in test tube B. (1 mark)
d) Specimen Y is an organ in animals. Name the organ and state two other functions apartfrom
detoxification.
Name of organ (1 mark)
Functions (2 marks)

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