BIOLOGY

(MOCKS EXAMS 1-10)

Compilation of 10 Annual Joint Biology Mock Trials amongst our KCSE 20

Schools in the whole Republic of Kenya.

INCLUSIVE OF BOTH PAPER 1 & 2 EXAMS.

KEY TO SUCCESS!
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 1
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Kenya Certificate of Secondary Education.

Answer All the Questions
1. How does growth as a characteristic of living organisms differ in plants and animals ?
(2marks)
2. a)State the role of active transport in animal nutrition (1mark)
b) Cyanide lowers the rate of active transport. Explain? (2marks)
3. The figure below is a diagram of a vertical section of a mammalian tooth.

A B

D
(i) Name the part labelled A and B. (2 marks)

(ii)State two ways in which structure D is adapted to its functions. (2 marks)

 (iii) List two ways of preventing gingivitis. (2 marks)

4. The figure below shows % saturation of oxygen in blood in fish as water passes
along the gill plate.

% Water
Blood
saturation
of oxygen

Distance along the gill plates

(a) (i) Name the type of blood flow shown in the gill plate. (1mark)

(ii) Explain the advantage of the type of flow named in a (i) above (2marks)

(b) State two organs in humans which display the type of flow named in a (i) above
(2marks)

(c) State two ways in which floating leaves of aquatic plants are adapted to gaseous
exchange (2marks)

5. The equation below shows an oxidation reaction of food substances.

C51H98O6 + 145O2 ------- X CO2 + 98 H2O + energy
a) What do you understand by the term respiratory quotient? (1mark)
b) Determine respiratory quotient of the oxidation of food substance. (2marks)
c) Identify the food substances. (1mark)
6. When any one of the growth parameters such as growth in size or weight, increase
in number of cells are plotted in a graph against time like below, a clear curve is
obtained
 State its name.........................................................................................(1mark)

7. The graph below represents the growth in a certain phylum.

How does this differ from growth in humans? (1mark)

8. The embryo of a dry, fully developed seed usually passes through a period of rest after
ripening period and it cannot germinate even when provided with all favorable conditions.
State the significance of this. (2marks)

9. a) Cowpeas seeds were place in a vacuum flask and left for five days. What is the
expected change in composition of gases in the flask on the sixth day? (1mark)
b) Give a reason for your answer in (a) above (1mark)
10.Biotechnologist works day a night to curb food insecurity using the knowledge of polyploidy
in genetics. Explain the economic importance of such practice? (2marks)
b) Define a backcross? (1 mark)
11. The structure below was obtained from an animal cell

a) What is the name of the hair like processes and state its function? (2marks)
Name
Function
b) From which parts of the mammalian body are these structures found? (1mark)
c) State the effect of cigarette smoking to the structure? (1mark)
12. A student was found to have blood group B+
a) What type of antibody is present in his plasma? (1mark)
b) Which antigens are present in this blood group? (1mark)
13.Plants relatively have less waste to excrete than animals. Give two reasons to explain
this observation (2marks)
14. State two methods by which plants get rid of their waste products (2marks)
15. To estimate the population size of mosquitoes in Banji village that covers an area of
25km2, visiting researchers caught 400 mosquitoes which they marked and released. After
24 hours, 200 mosquitoes were caught out of which 120 had not been marked.
(a) Suggest the sampling method described above. (1 mark)
(b)What are the disadvantages of this method? (2 marks)
16. The table below shows stomatal distribution on leaves A and B and their surface area.
Use the information to answer the questions.
Leaf surface A B
Number of Upper leaf 20 5
stomata surface
Lower leaf 0 15
surface
Surface area 25 cm2 18cm2
Identify with reasons the habitats of the plant from which the leaves were obtained.
Leaf A: (2 marks)
Habitat ……………………………………………..….…………..…………..
Reason ……………………..………………….…..….….…..……………….
Leaf B: (2 marks)
Habitat ………………...……………………………………………………………
Reason
17. Name the causative agent of the following diseases (2 marks)
(i) Trichomoniasis.
(ii) Gonorrhea
18. The diagram below shows a pollen tube as it develops down the style. Use it to answer
the questions that follows;

(i) Name the part labelled G. (1 mark)

(ii)State two functions of structure labelled E. (2 marks)
19. (a) Define parthenogenesis? (1 mark)
(b) Name the plant hormone that induces fruit ripening. (1 mark)
20. A group of Form Three students collected a certain specimen for study as
shown below. Study it carefully and use it to answer the questions that follow.

(i) Name the type of metamorphosis in the above specimen. (1 mark)

(ii)Give any two advantages of the above metamorphosis. (2 marks)
21. (i)Give two structural features in a leaf that adapts it to absorb Carbon (IV) Oxide.
(2 marks)
(ii) Name the cell organelle in which Carbon (IV) oxide combines with water to form
a complex organic compound takes place (1 mark)
22. In an experiment to investigate a factor affecting photosynthesis; leaf of a potted
plant, which had been kept in the dark overnight was covered with an aluminum foil
as
shown in the diagram below. The set up was kept in the sunlight for three hours after
which a food test was carried out on the leaf.

(a) Which factor was being investigated in the experiment? (1 mark)

(b)Which food test was carried out? (1 mark)
(c) State the results of the food test. (1 mark)
23. Explain how the following plant adaptations minimizes rate of transpiration (2marks)
a) Sunken stomata
b) Thick cuticle
24. Explain how drooping of leaves on a hot sunny day is advantageous to a plant(2mks)
25. Name two tissues in plants which are thickened with lignin (2marks)
26. The diagram below shows the front view of a male reproductive system.

a) Give the functions of the structures labelled X and V (2marks)

b) What is the role of Follicle Stimulating Hormone in male reproduction?
(1mark)
27. Explain why the concentration of insecticides in fish eating birds may be
hundreds of times greater than its concentration in the water where the fish live
(3marks)
28. The diagram below shows a stage in meiosis

State the biological significance of the stage represented on the diagram above (1mark)

29. How do the following factors hinder self-pollination in flowering plants? (3marks)

a) Self-sterility
b) Heterostyly
c)Protogyny
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 1
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) In human beings, a downward pointed frontal hairline (“windows peak”) is a
heritable trait. A person with windows peak always has at least one parent who has
this trait; where as persons with frontal hairline may occur in families in which one
or even both parents have windows peak. Using W and w to symbolize genes for this
trait
a) Determine the F1 generation if a homozygous windows peak male parent is married
to a homozygous frontal hairlined female parent (4mks)
(b) State two causes of variations (1mk)
c) Name two sex linked genetic disorders affecting human females and males (2mks)
What is genome
2) The diagram below shows an organism obtained from an aquatic ecosystem
(a) State the kingdom in which the organism belongs. (1mk)
 (b) Name the parts labeled (1mk)
a. B
b. Y (1mk)
State the functions of the following parts
A (1mk)
X (1mk)
Z (1mk)
(d)Explain briefly why the organism is described as eukaryotic (2mk)
3) a) The diagram below shows some of the features of a synovial joint. Study the
diagram carefully and answer the questions that follow.

Name the type of synovial joint. (1 mark)

Name the parts labeled J, and L (2 marks)
State two roles of the part labeled L. (2 marks)
Suggest one advantage of this type of joint. (1 mark)
State how the following tissues are adapted to provide mechanical support in plants
(2mks)
a. Parenchyma
b. Collenchyma
4) A student set up an experiment using soaked and dry seeds as shown below

State the objective of this experiment (1mk)

State the observations made in each of the flask after 24 hours (2mks)
Account for the observation made in (b) above (2mks)
Suggest why vacuum flasks were used in this experiment (1mk)
What alteration would you make in the set-up to make the results more reliable (1mk)
Why should the seeds be washed with antiseptic/10% formalin? (1mk)

5) a) Explain how the following meristematic tissues contribute to growth of higher

plants
i) Vascular cambium (2mks)
ii) Cork Cambium (2mks)
The diagram below shows a life cycle of a cockroach

a) Name the hormone that would be at high concentration during.

 First week (1mk)
Second week (1mk)

Name the structure that produces hormone in a (ii) above (1mk)

Name the series of stages through which the nymph undergoes to reach adult stage
(1mks)

SECTION B (40 Marks)

Answer question 6 (Compulsory) and either question 7 or 8
6) The menstrual cycle is a sequence of events repeated monthly in the female
production system. The table below shows the concentration of oestrogen and
progesterone hormones and body temperatures of female against time.

Time in days Oestrogen Progesterone Temperature in 0oc

mg/100cm of mg/100cm3 of
blood blood
1 20 0 36.4
2 20.5 0 36.6
3 25 0 36.7
4 27.5 0 36.8
5 30 0 36.7
6 32.5 0 36.6
7 35 0 36.8
8 40 0 36.7
9 48 0 36.6
10 56 0 36.8
11 64 0 36.7
12 72 0 36.6
13 80 0 36.4
14 170 20 36.3
15 140 50 36.6
16 80 80 37.0
17 70 130 37.2
18 65 170 37.0
 19 60 160 37.1
20 65 150 37.15
21 130 130 37.2
22 140 110 37.1
23 130 90 37.0
24 100 70 37.1
25 80 50 37.2
26 60 20 37.0
27 20 0 36.4
a). Using the same axis draw graphs of oestrogen and progesterone against time/days
(8mks)
b) State the possible event taking place in the uterus during the first week? (1 mark)
c) State the events taking place in the ovary between day 1 and day 13. (2 marks)
d) Account for the sudden increase in the progesterone concentration between day 14
and day18. (2 marks)
e) Account for the change in temperature between day 14 and 17. (1 mark)
f) Account for the change of the curve of progesterone between day 19 and 27. (2marks)
a) State the function of the following.
(i) Ovary (1mark)
(ii) Progesterone (1 mark)
(iii) Oestrogen (1 mark)

7 a) Describe how the following evidences support the theory of organic evolution:
geographical distribution, fossil records and comparative anatomy (10mks)

b) Explain tropic responses in plants and their survival values (10mks)

8 a) Describe the structural adaptations of mammalian heart to its Functions

(10mks)

b) Explain the role of osmosis in organisms (10mks)

 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 2
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) a) Define the term specimen. (1mk)
Give two significances of collecting specimens in biology. (2mks)
2) . Give three reasons why Drosophila melanogaster is considered suitable for use in
genetic experiments. (3mks)
3) List two factors you would consider before selecting a microscope for use in a
biological study. (2mks)
4) A group of form two students placed a fresh leaf in warm water. They observed that
air bubbles formed on the surface of the leaf.
a) What biological process were they investigating? (1mk)
Name the structures from which the air bubbles were coming from. (1mk)
Explain the distribution of the structures named in (b) above on the leaf surfaces of an
aquatic plant. (2mks)
5) Differentiate between hydrolysis and condensation. (2mks)
6) (a) Which sets of teeth would be used in chewing sugarcane for maximum extraction of
sap? (2mks)
(b) What is the advantage of heterodont dentition over homodont dentition? (1mk)
 (b) During digestion name the enzyme that acts on the sugarcane sap and give the final
products. (2mks)
Enzyme
Final products
 7) Study the diagram below and answer the questions that follow.

a) The part labelled X turned blue black after iodine solution was applied on the cut
cross section of the above specimen
a. Name part X (1mks)
b. Give a reason for your answer. (1mks)
b) State two phenomenons of stomata which reduce the rate of transpiration. (2mks)
8) a) What is respiratory quotient? (1mks)
b) Explain why it is difficult to measure respiratory quotient in plants. (2mks)
9) Study and complete the table below. (3mks)
Character Monocot Dicot
a) Number of stamens
b) Arrangement of
vascular bundle in stem
c) Type of root

10) The diagram below shows blood circulation in a mammalian tissue.

a) Give the name of the above section of the blood circulation system. (1mks)

b) Explain two the adaptation of the above section to its function. (2mks)
 What is the name of blood vessel Q. (1mk)
11) Differentiate between dioecious and monoecious plants. (2mks)
12) a) Why does endosperm weight of a germinating seed decrease as the weight of the
shoot increases. (l mks)
b) State three importance of the pupa stage of metamorphosis to insects. (lmks)
13) The diagrams below show a pair of homologous chromosomes. Study them
and answer the questions that follow.

State the phenomenon shown above. (lmk)

What is the genetic significance of the phenomenon above? (lmk)
Name the type of mutation caused by the above phenomenon. (2mks)
14) In an experiment to determine the population of Tilapia fish in a school fish
pond, students of Canada school decided to use capture-recapture method.
a) Name three vital tools the students would need for the exercise. (3mks)
b) State two factors that might affect the accuracy of their results. (2mks)
15) The table below show description of sizes of glomeruli and renal tubules of
two animals, which are in different environments.
Animal Q Animal W
Glomeruli Few Many
Renal tubules Long Short

a) Name the likely environment in which each animal lives. (2mks)

Q–
W-
b) Suggest the main nitrogenous waste produced by animal W. (lmk)
What is the importance of the renal tubules being long? (lmk)
16) What is the role of the following hormones in human reproduction?
Follicle stimulating hormone in male (lmk)
Luteinizing hormone during menstrual cycle. (lmk)
17) Below is representation of an experiment that was carried out on a tree in
Kayombe forest.
 a) Which two tissues are removed in a ring bark experiment? (2mks)
b) Removal of the tissues above leads to some effects to the plant. Name these 2 effects.
(2mks)
c) State and explain the observation that would be made in the plant above after
some time. (3mks)
18) A section of nucleic strand contains the following sequence.
A — C — G — A — G — A — T — A— C
i) Write the complimentary DNA stand. (lmk)
Write the mRNA strand of the strand in (a) above. (lmk)
b) Name the site for protein synthesis in a cell. (lmk)
State one disorder caused by non-disjunction mutation. (lmk)
19) i) State the importance of rings of chitin in the tracheal system of insects. (lmk)
a) Explain the significance of maintaining a steep concentration gradient in the respiratory
surfaces of animals. (lmk)
b) Explain why a bony fish dies shortly after being removed from water. (3mks)
20) Explain why Lamark’s theory of evolution is not accepted by modern scientist.
(2mks)
21) Name the branch of biology that deals with;
a) Relationship between antelopes and gazelles in their environment. (lmk)
b) Study of Ebola virus. (lmk)
Explain what would happen if a given of living things lose their ability to reproduce.
(lmk)
22) Explain the following when testing a leaf for starch.
i. Boiling the leaf in hot water. (lmk)
ii. Destarching (lmk)
iii. Boiling the leaf in methylated spirit. (lmk)
23) Explain why osmosis is a special type of diffusion. (lmk)
24) Explain three protective functions of the blood. (3mks)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 2
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) a) Digestive enzymes are made by different organs in the digestive system. Complete
the table below by putting a tick () or a cross (X) in the boxes. The first has been
done. (2mks)
Enzyme Salivary Stomach Pancrease Ileum
glands
Amylase a.  b. X  

lipase
Protease

Name the features that increase the surface area of small intestines. (2mks)
Name the vitamin which is associated with citrus fruits and green vegetables. (1mk)
What food nutrient would be found in the villi of ileum few hours after a meal of
boiled rice? (1mk)
Caecum is poorly developed in humans. Name the group of mammals in which its well
developed and outline its role. (2mk)
2) The diagram below shows the structure of a chromosome.
a) Identify the parts labelled D and E. (2mks)
Name:
a. Two organelles in an animal cell where DNA is found. (1mk)
b. The process whereby DNA makes an identical copy of itself. (1mk)
b) Coat colour in cats is determined by a sex linked gene with two alleles, black and
orange. When black cats are mated with orange cats, the female offspring are always
tortoise shell, their coats show black and orange patches of various sizes, while the
male offspring have the same coat colour as their mothers. Using symbols (B) for
black and (O) for orange, draw a punnet square to account for a cross of tortoise shell
female with an orange male.
(4mks)
3) A form 2 student wanted to investigate the effect of temperatures on the rate of carbon
(IV) oxide production by yeast. He set up the apparatus as shown below.
a) The student varied the temperatures of the water bath between 150c – 650c. He
measured the rate of carbon (IV) oxide production by counting the number of
bubbles per minute.
Sketch the shape of the graph that the student would obtain on the axes below. (3mks)

a. Account for the shape of the graph. (1mk)

b) Give two variables that the student would need to keep at constant in his experiment.
(2mks)
i) Yeast is used in production of beer. Write the equation for the respiration of yeast
that occurs during production of beer. (1mk)
Suggest why lactic acid produced in the body is not highly excreted out of the body.
(1mk)
4) The diagram below represents the relationship between the blood system of the
foetus and that of the mother. The arrows indicate the direction of blood flow in the
blood vessels.
a) Apart from diffusion of substances from the mother’s blood to the foetus blood and
vice versa, state two other functions of the placenta. (2mks)
b) i) Name the blood vessels C and D. (2mks)
b) ii) State two differences between the composition of blood found in blood vessel C
and blood found in blood vessel D. (2mks)
C D

Explain one consequence for the foetus if blood vessel D becomes blocked preventing
blood flow. (2mks)

5) The diagram below is of a mammalian nephron and associated structures.

a) i) Identify the parts labelled D and E. (2mks)

Reabsorbtion of substances takes place along the regions labelled B-E. Which two
letters correspond to the regions in which most water is reabsorbed? (1mk)
b) The table below summarizes differences in the concentration of some substances
in the blood plasma and the renal filtrate at the end of the proximal convoluted
tubule.
Substances Concentration in blood plasma Concentration in filtrate at the
end of PCT
Proteins 12 0
Glucose 0.15 0
Urea 0.04 0.09
Explain the results. (3mks)
In mammals there is a strong positive correlation between the length of the loop of
henle and the degree of aridity (dryness) of the environment that a mammal such as the
desert rat inhabits. Explain this relationship. (2mks)
 SECTION B (40marks)
Answer question 6 (compulsory) and either question 7 or 8
6) The table below contains information on changes that occur in a river,
downstream from sewage outflow.
Distance downstream Concentration Number of organisms (arbitrary
from point of sewage dissolved oxygen units)
entry (m)
(%) Bacteria Algae Fish
0 95 88 20 20
100 30 78 8 6
200 20 74 6 2
300 28 60 20 0
400 42 50 40 0
500 58 48 70 0
600 70 44 84 0
700 80 42 90 0
800 89 38 84 0
900 95 36 68 4
1000 100 34 54 20
a) Plot a graph of number of organisms against distance downstream. (7mks)
6. b) Describe the changes in the concentration of oxygen dissolved in the water
downstream from the point of sewage entry. (2mks)
b) Account for the changes in the numbers or each of the following
organisms downstream.
a) Bacteria (3mks)
b) Algae (3mks)
c) Fish (3mks)
c) State two ways in which the degree of water pollution covered by sewage can be
reduced. (2mks)

7. Describe the evidences of organic evolution. (20mks)

8. a) Describe the process of fertilisation in a flowering plant. (15mks)
b) State the changes that take place in a flower after fertilization. (5mks)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 3
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. The study of biology enhances international cooperation, as countries work
together to solve environmental problems. Name 2 biology related international
conventions that help solve environmental problems. (2 marks)
2. A zebra is observed to be grazing at a grassland. Apart from nutrition, name one
other characteristic of living things observed on the zebra as it grazes. (1 mark)
3. The diagram below represents an organism. Study it and answer the questions
that follow.
a) Identify the kingdom to which the organism belongs (1 mark)
b) Name the structures labelled X (1 mark)
 c) Identify the type of nutrition carried out by the organism and give a reason (2 mks)
Type of:
Nutrition
Reason

4. The diagram shown represents part of a cell.

a) Identify the structure (1 mark)

b) Label the following parts: (2 marks)
P………………………………………………………………………
Q…………………………………………………………………………
5. Name the following organelles. (3 marks)
a) Contains chromatin material
b) Forms spindle fibres
c) Digests pathogens that enter the cell
6. The bacterium that causes typhoid is known as salmonella typhi.
a) Write the scientific name correctly (1 mark)
b) State the main mode of transmission of the above organism. (1 mark)
7. Three stems of tradescantia of equal length were placed in three solutions of
different concentrations. The set ups were left to stand for 30 minutes. The results
were recorded in the table below.
Solution Initial length of stem Final length of stem (mm)
(mm)
A 37 37
B 37 35.2
C 37 39.7

a) Describe the nature of solution A in relation to the final length of the

tradescantia stem. (1mark)
 b) Explain the observation that was made on the tradescantia stem which was put in
solution B. ( 2marks)
c) State what would happen to red blood cells if they were placed in solution C.
(1 mark)
d) A KASSUME researcher found out that oxygen concentration and sugar
consumption is directly related to potassium ion uptake in wheat roots. Name the
process by which potassium ions is taken by the roots. Give a reason for your
answer ( 2 marks)

8. The diagram below is an experiment that was carried out to investigate a

certain biological process. Study it an answer the questions below.

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

b) Which specialised tissue was removed in the above experiment? ( 1mark)
c) How is the tissue named above adapted to perform its function? ( 1mark)
d) Predict in diagrammatic form the fate of the trunk after 3 weeks? ( 1 mark)
9. Two potted plants A and B that had been kept in dark for 48 hours were placed
in polythene bags.
 NaOH NaHCO3
pellets

set up A Set up B

Into set up A, a dish of sodium hydroxide was placed inside the polythene bag. In the
set up of plant B, a dish of sodium hydrogen carbonate was similarly placed. The plants
were then placed in sunlight for six hours. After six hours a leaf from each plant was
tested for starch.

(a) What is the expected results for set up A (1 mark)

(b) What was the purpose of:
(i) Sodium hydroxide (1 mark)
(ii) Sodium hydrogen carbonate. (1 mark)
(c) What would have been the case if neither sodium hydroxide nor sodium
hydrogen carbonate were placed in the set up? (1 mark)
(d) State the purpose of this experiment. (1 mark)
(e) Explain how the teeth of a lion are adapted to carnivorous mode of feed. (2 marks)

10.Explain how emotional state of the body affect heart beat rate. (1 mark)
11.(i) What is meant by immune response? (1 mark)
(ii) Name one cell responsible for immune response in a human being.(1 mark)
12.Describe the mechanism of closing the stomata on the basis of photosynthetic theory
(3 marks)
13.Explain how the floating aquatic plants are adopted of gaseous exchange. ( 1 mark)
14.The chart below shows a summarized process that occurs in animals.

Reactions Lactic acid + N

in cytoplasm
 Process X
Glucose Substance A + ATP

Reactions
in matr
Product B + water + ATP

(a) Name the: (3 marks)

(i) Process X ......................................................................................................
(ii) Substance A
(iii) Product B .....................................................................................................
(b)State the condition necessary for the reactions in matrix to occur. (1 mark)
15. Explain the roles of the following plant hormones
(i) Gibberellins (3 marks)
(ii) Ethylene (2 marks)
16. (a) Define the first law of heredity as postulated by Gregor Mendel (1 mark)
(b) A common species of rats has individuals with white, black or grey coats.
During a study, a rat with white coat was crossed with a rat with black coat. Both
parents were pure lines. All the offspring in F1 generation had grey coats. The F1
offspring were selfed to get F2. Using letter B to represent the gene for black
coat and W for white coat, work out the phenotypic ratio of F2 offspring. Show
your working. (4 marks)
17. What is meant by the following terms
(a) Natural selection (2 marks)
(b) Struggle for existence
18. Despite the best efforts to make and use the most effective pesticides, bedbugs
have not been eradicated from most homes. Give an explanation for this
observation.
(2 marks)
19. The diagram below illustrates the mechanism of blood glucose concentration

Corrective mechanism A

Excess
Normal glucose level Normal glucose level

Deficiency
Corrective mechanism B
What principle of homeostasis is illustrated in the diagram? (1 mark)
Name the condition that may result from further excess (1 mark)
State how the corrective mechanism B restores blood glucose to normal level (2 marks)
20. The diagram below shows a stage in cell division
 (a) Name the type of cell division? (1 mark)
(b)Give two reasons for your answer in (a) above (2 marks)
(c) State two differences between the end products of mitosis and meiosis (2 marks)
21. Study the diagram below and use to answer the questions that follow;

a) Identify the sampling method illustrated. (1 mark)

b) Describe how the sampling method above was used to estimate the population
of organisms (4
mark)
c) Give any two assumptions that would be made when estimating the
population the named organism in (a) above (2 marks)
d) Differentiate between the terms; habitat and ecological niche (1 mark)

22. Study the food relationship below and answer the questions

Nile perch
 Frog Tilapia Gray fish

Mosquito larva

Green algae

a) State the ecosystem from which the above food web was obtained (1 mark)
b) What will be the effect of increased fishing of nile perch on the number of malaria
cases. (2
marks)
c) How is malaria transmitted from infected person to a healthy person (1 mark)
d) What will be the benefit of controlling malaria in the above ecosystem using
biological control (2 marks)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 3
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. The following is an illustration of a certain process that occurs in mammals

+ Juice X process P

A fat molecule

(a) Name process P.............................................................................................(1mark)

(b) Name the juice involved in the process P (1 mark)

(c) List two Salts found in the juice name in (b) above that aids in process P (2 marks)
(d) Give a reason why liver damage leads to impaired digestion of fats (1 mark)

(e) What would be the likely effect on digestion if the small intestine of a human is
reduced in an operation? (2 marks)
(f) State the fate of excess glucose in the human body. (1 mark)
2. The diagrams below shows samples of blood obtained from two different persons A
and B.

Blood sample from person A Blood sample from person B

a) What genetic disorder is person B suffering from? (1 mark)
(b) State one advantage and one disadvantage of the disorder in (a) above when
its in heterozygous state. (2 marks)

(c) Work out the genotypes and phenotypes of the resulting offsprings of
marriage between person A and person B (5 marks)
3. The diagram below represents the pathways of water from the soil into the plant.

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

(b) Explain how water moves from point X to Z. (5mks)

4. During an ecological study of a grassland ecosystem, a group of students recorded

the following observations.
i. Grasshoppers feed on grass
ii. Guinea fowls feed on grasshoppers, termites
iii. Vultures feed on guinea fowls and leopards
iv. Leopards feed on gazelles
v. Termites feed on grass
vi. Gazelles feed on grass
(a) From this record of observations construct a food web. (4 marks)
(b) Write down, the food chains in which the guinea fowls are secondary consumers.
(2 marks)
(c) Name the organisms through which energy from the sun enters the food web. 1 mark)
(d) Name the organism that has the least biomass in the food web. (1mark)

5. Below is a chemical equation, study it and answer the questions that follow:-
A
Carbon (IV) oxide + water Oxygen + glucose
B
(a) Name process A and B (2 marks)
(b) What is the biological significance of process A (1 mark)
(c) In which organelle does process A and B take place? (2 marks)
(d) Name two stages of process B (2 marks)
(e) Define compensation point ( 1mark)

SECTION B (40 MARKS)

Answer Question 6 (Compulsory) And Either Question 7 Or 8
6. The graph below shows changes in pH and oxygen saturation in river water over a 24
hour period

% Oxygen saturation

Key

pH value

…………. % saturation of oxygen

a) when is the pH value and dissolved oxygen saturation % highest? (2 marks)

(b) Account for the pH value recorded
(i) Between 08.00 and 1.00 p.m (2 marks)

(ii) Between 2100 and 2400 midnight (2 marks)

(c) Explain the influence of light intensity on % saturation of oxygen dissolved in

this study (4 marks)
 (d) State two structural adaptations that the submerged plants in this river have,
which enable them to carry out photosynthesis (2 marks)
(e) Explain the variations that will be recorded if a similar study was carried out
in a river near a nitrate fertilizer industry. (4 marks)

7. Explain the various ways in which a typical cell is adapted to its functions (20 marks)

8. Discuss the causes, effects and control measures for water pollution (20 marks)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 4
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. Identify the characteristics of living organisms shown by the following; (2marks)
a) Bursting of the sporangium in Rhizopous.
b) A cheetah chasing after a gazelle.
2. Define the following terms as used in biology;
i. Entomology. (1mark)
ii. Histology. (1mark)
3. State three significance of Osmosis to plant nutrition. (3marks)
4. The diagram below represents amoeba. Study it and answer the questions that follow;

a) Name the respiratory surface found in the above organism. (1mark)

 b) i. Identify the structures labeled J. (1mark)
ii. State two functions of the structure named in (b) (i) above. (2marks)
5. Below is a diagram of a mammalian cell. Study it and answer the questions that follow.
a) Identify the structures labeled; (2marks)

G. …………………………………………………..
M. …………………………………………………..
b) State the function of the structure labeled M. (1mark)

6. Give two roles of the colon in human digestive system. (2marks)

7. Distinguish between dentition and dental formula. (2marks)
8. Name a carbohydrate that is abundance in the following;
a. Ripe fruits. (1mark)
b. Blood of vertebrates. (1mark)

9. Apart from photosynthesis identify one other function of chloroplast in plants. (1mark)
10.Below is a transverse section of a root. Study the diagram and answer the question that
follows.

a) Identify the class from which the section was obtained. (1mark)
b) Give a reason for your answer in (a) above. (1mark)
c) State one adaptation of endodermis to its function. (1mark)
 d) Name two tissues found in the cortex. (2marks)

11. Distinguish between Guttation and transpiration. (2marks)

12.During a field study, students from Kenya high school found a woody plant as
illustrated below.

a) Identify the above structure. (1mark)

b) Give two adaptations of the structure named in (a) above. (2marks)
c) Where is the above structure located in halophytes? (1mark)
13.State two structural differences between a cell wall and a cell membrane. (2marks)
14.a) Identify the cells that secrete the following along the alimentary canal.
i) Hydrochloric acid. (1mark)
ii) Rennin. (1mark)
b. State two significance of smooth muscles in the digestive system. (2marks)
15.During an investigation of a certain metabolic reaction, students set up the apparatus as
shown below.
 a. Identify the physiological process being investigated. (1mark)
b. Account for the observation made in the conical flask after 30 minutes. (2marks)
16.a) State three ways in which human skin protects the body against bacterial infection.
(3marks)
b, Name the protein found in the Malpighian layer of the skin and state its
function. Name..............................................................................................(1mark)
Function...........................................................................................................(1mark)
17. A student mixed a sample of urine from a person with Benedict’s solution and
heated, the colour changed to orange.
a) What did the student conclude on the health status of the person? (1mark)
b) Which organ in the person may not be functioning properly? (1mark)
18.An investigation was carried out on a mammalian kidney.

i. Name the structure labeled T. (1mark)

ii. What is the function of the structure named in (i) above in the kidney.(1mk)
 iii. Identify the disease shown in the kidney above. (1mark)
19.State the importance of Saprophytic fungi in an ecosystem. (1mark)
20.List two assumptions made when using Capture-recapture as a method of estimating
population. (2marks)
21. Give two reasons why Pteridophytes are considered more advanced than Bryophytes.
(2marks)
22. Study the diagram below and answer the following questions.

a) State the function of the part labeled Q. (2marks)

b) State the role of the part labeled R. (1mark)
c) Identify a hormone produced by part labeled P. (1mark)
23.Give the function of Prolactin in female reproductive cycle. (1mark)
24.Below is a photograph illustrating a germinating seedling.

a) Identify the type of germination. (1mark)

b) Give two functions of the structure labeled Z? (2marks)
 c) What the name given to the part labeled W? (1mark)
d) Explain how seedling H responds to light causing it to straighten. (2marks)
25.a) Define vestigial structures? (1mark)
b) State two examples of vestigial structures in man. (2marks)

26.The figure below shows some cells from parts of mammalian respiratory tract.

a. Identify the part of the respiratory tract where the cells were obtained from.
(1mark)
b. Explain the role of: (2marks)
i. The mucus
ii. The cilia.
27. Mycorrhiza is a symbiotic association between two organisms. Name the two
organisms that make this association. (2marks)
28. State the significance of diffusion in the following;
a. Pollination. (1mark)
b. Skeletal muscle cell. (1mark)
29. Explain the significance of the following;
a) The cardiac muscle is myogenic. (1mark)
b) The left ventricle of a mammalian heart is more muscular than right ventricle.
(1mark)
c) Most of carbon (IV) oxide is not dissolved in the blood plasma. (1mark)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 4
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) 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 some time, the students observed that the level of sugar solution had risen.
(b) What physiological process was being investigated? (1mk)
(c) Account for the rise in the level of sugar solution in this experiment. (4mks)
(d) (i) State the results the students would obtain if they repeated the experiment using a
 piece of boiled pawpaw. (1mk)
(ii) Give a reason for your answer in (c) (i) above. (2mks)
2) Use the diagram below to answer the questions that follow.

(e) (i) Name the parts labelled A, B and C. (3mks)

(f) State the function of the part labelled C. (1mk)
(g) Explain the difference between pulmonary circulation and systemic circulation.(2mk)
(h) What is the advantage of having a double circulatory system over a single circulatory
system? (2mks)
3) In an investigation, a variety of pea plants grown from seeds with smooth coats were
crossed with plants grown from seeds with wrinkled coats. All the seeds obtained in
the first filial (F1) generation had smooth seed coats.
(i) Using letter R to represent the gene for smooth seed coat, work out the genotypes of
the F1generation. Show your working. (3mks)
(j) If F1 generation was selfed, determine the phenotypic ratio of the second filial (F2)
generation. Show your working. (4mks)
(k) If the total number of seeds in the F2 generation was 14640, calculate the number of
seeds with wrinkled coats. Show your working. (1mk)
4) The apparatus below was set up by a student to find out the changes in gases
during germination of bean seeds. Study it and answer the questions that follow.
 (l) After 48 hours the level of water in U-tube A had dropped and rose in B as indicated
above. Explain this observation. (3mks)
(m) The equation below shows the process that takes place in mammalian
muscles. 2C51H98O6 + 145O2 102CO2 +
98H2O + Energy
Calculate the respiratory quotient from the equation above. (2mks)
Identify the substrate being respired from the equation above. (1mk)
Explain why it is difficult to calculate the respiratory quotient in plants. (2mks)

2) The diagram below illustrates the components of a simple reflex that takes place
when a person’s finger is accidentally pricked by a sharp pin.

(a) Name the neurones labelled X and Y. (2mks)

(b) State one function of the fluid found in the part labelled Z. (1mk)
(c) Explain how the above simple reflex action takes place. (5mks)

SECTON B (40 MKS)

Answer question 6 (compulsory) and either question 7 or 8
6) In a population growth, two species of flour beetles, Tribulum confusum and Tribulum
casteanum were grown in a box with unlimited supply of flour (food). The box was
kept at 240C and 30% relative humidity. The beetles were counted at certain intervals
and the results tabulated as shown below.
 No. of days 0 1 5 6 80 10 12 14 18 20
after 0 0 0 0 0 0 0 0
introduction
No. T. 2 2 3 8 13 14 16 16 16 16
of confus 0 0 0 0 30 40 20 00 20 00
beetl um 0 0
es
prese T. 2 2 3 4 50 40 15 60 20 10
nt in castean 0 0 0 3 0 0 0
the um
0 0
box

(n) Using the same axis, draw graphs of number of beetles in the box against time.
(8mks)
(o) How many beetles were present on the 76th day? (2mks)
T.confusum..........................................................................................................................
T.casteanum........................................................................................................................
(p) Account for the shape of T. confusum curve between day 1 and 180. (5mks)
(q) (i) What happens to T. casteanum between day 80 and 160? (1mk)
What biological phenomenon is represented by observation in (d) (i) above? (1mk)
(r) State any three factors that determine the distribution of animals in their habitat.
(3mks)

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. (9mks)

(b) Describe the adaptations of flowers to insect pollination. (11mks)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 5
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. Identify the following. (2mrks)
i. Type of movement in cells.
ii. Arrangement of leaves on a plant.
2. Explain how adequate water supply increases the rate of glucose formation in plants.
(1mrks)
Name the element obtained from insects by insectivorous plants. (1mrk)

3. A mushroom research station would like to employ a researcher. Which scientist is

most appropriate. (1mkr)
Name the branch of biology that deals with phylogenetic relationship between
organisms. (1mrk)
4. State the role of the diaphragm.
i. In the light microscope. (1mrk)
ii. During ventilation in man. (1mrk)
5. Explain why plants absorb water in waterlogged soil but not mineral salts. (2mrks)
6. A biological washing detergent removes stains like oils from cloths.
i. Name the enzyme that it contains. (1mrk)
 ii. Explain why the stains would be removed faster with the detergent in water at
35oc rather than at 15Oc. (1mrk)
7. Below is a diagram of an embryo sac.
 J

Identify the structures labelled.

(2mrks) J-
K-
8. Explain why low temperature will cause seed dormancy by not very high temperatures.
(1mrk)
9. Explain why the average length of the chicken egg is 6cm while that of a human
is 0.1mm. (1mrk)
Identify two features that enable mammalian fallopian tubes perform their function.
(2mrks)
10.State a limiting factor of using a potometer to measure the rate of transpiration. (1mrk)
Name the tissue that transports hormones in plants. (1mrk)
11.To control the spread of malaria, fish are introduced into water bodies near
residential
area.
a. Name this method of population control. (1mrk)
b. State an advantage of the above method. (1mrk)
12.Apart from vaccination, state two ways of controlling highly infectious disease among
animals. (2mrks)

13. Name the enzyme that breaks down hydrogen carbonate ions in mammalian blood to
release carbon (IV) oxide. (1mrk)

Explain why obligate anaerobes die in presence of oxygen. (1mrk)

14. Name the group of sporangia born on fern leaves. (1mrk)

Why are fruits not produced in gymnosperms? (1mrk)

15. Explain why lactating mothers need extra energy. (1mrk)

State the function of interstitial cells found in the testes. (1mrk)
16.Below is a diagram showing a foetus in the uterus.

state two observations showing that parturition is about to take place. (2mrks)

17.The symptoms of typhoid disease include high fever, vomiting and diarrhoea. Explain
why they may lead to death if not treated. (2mrks)
18. The table below represents a chromatid which undergoes a mutation, the letters genes.
Before mutation
L M N O P Q
After mutation
L O N M P Q

a. Name the type of mutation. (1mrk)

b.
i. Identify the nucleic acid whose base sequence is shown below. (1mrk)
G-A-C-U-A-G-A-C-G
ii. If the above strand was involved in protein synthesis, how many
amino acids would the protein have? (1mrk)
19.Explain why resistance to antibiotics is considered an example of evolution. (2mrks)
20.People are encouraged to take the corona virus disease vaccine. How does it work?
(1mrk)
What is the significance of;
i. Red blood cells lacking mitochondria. (1mrk)
ii. Xylem vessels being dead. (1mrk)
21. Use of fossil fuel as source of energy causes global warming. Governments are
being encouraged to use ‘clean energy’. State two sources of this energy. (2mrks)
22. An athlete training to take part in an international competition moved to a high
attitude area to train for 12 days. He took his pulse rate per minute and recorded as
shown below.
Day 1 2 3 4 5 6 7 8 9 10 11 12
Pulse rate 72 78 89 92 92 90 86 80 77 74 72 72
Account for the change in the pulse rate from.
i. Day 1-5. (2mrks)
ii. Day 6-12. (2mrk)
23.A patient complained of frequent thirst. A sample of the patient’s urine was found
not to have any sugar.
i. Name the hormone the person was deficient of. (1mrk)
ii. Name the gland that secretes the above hormone. (1mrk)
24. The paddles of a whale and fins of a fish adapt them to aquatic habitat.
i. Name the evolutionary process that may have given rise do
these structures. (1mrk)
ii. What name is given to such structures? (1mrk)
State two advantages of natural selection. (2mrks)
25.Explain why ingestion of salty food may reduce the amount of water passed out
in
urine. (2mrks)
Explain why small birds puff their features when cold. (2mrks)
26.Explain why halophytes have pneumatophores. (1mrk)
Explain how the following features adapt root hairs cells to absorption
i. Large sap vacuole. (1mrk)
ii. Numerous mitochondria. (1mrk)
27.A certain metabolic pathway takes place following
sequence. J-K-L-M-N
An inhibitor was added to the reactants during an experiment. At the end of the
experiment, there was more K and little L, M and N.
a. At what stage of the sequence was the inhibitor added. (1mrk)
b. Briefly explain how the inhibitor affected the reaction. (2mrks)
28.Suggest a change in the diet of a person whose liver is damaged. (1mrk)
a. State the importance of caecum in herbivores. (1mrk)
b. Name the polysaccharide that offers mechanical support in;
i. Arthropods (1mrk)
ii. Plants. (1mrk)
29.
a. Explain why an effective respiratory system is associated with the
circulatory system. (2mrks)
 b. Distinguish between haemoglobin and myoglobin. (2mrks)
30.
a. New born babies have a higher heart beat than adults. Explain why? (2mrks)
b. What Is the advantage of oxyhaemoglobin over carboxyhaemoglobin? (1mrk)
31. Explain why;
i. Fish pass a lot of water over the gills frequently. (1mrk)
ii. Lack of magnesium leads to yellowing of leaves. (1mrk)
32.The organisms below belong to kingdom Animalia.

a. Name the phylum and class where they belong. (2marks)

i. Phylum…………………………………………………………………
ii. Class
b. Give a reason for placing the organisms in the class in (a(ii) above. (1mrk)

KCSE 2024 TOP-SCHOOLS’ MOCKS

 MOCK TRIAL 5
BIOLOGY
PAPER 2
TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) The diagram below illustrates the structure of the kidney nephron.
(a) Name the part labeled E. (1 mark)
(b) How is the part labeled F adapted to its function? (4 marks)
 (c) State three physiological mechanisms of controlling the human body
temperature during a cold day. (3 marks)
2) The genetic disorder hemophilia is due to a recessive sex linked gene .A man who is
hemophilic marries a woman who is carrier for the condition.Using letter H to
represent the gene normal condition and letter h for the gene for hemophiliac condition.
i) What is the genotype for the man and the woman? (2marks)
ii) Work out a cross between the man and woman (3marks)

What is the chance that both the first and second sons will be hemophiliac? (2marks)

Hemophilia is more common in males than in female humans. Explain (1mark)

3) The diagram below represents a state in cell division. Study it and answer the questions
below.

Name the stage of cell division illustrated in the diagram above. (1 mark)
Name the parts labelled A, B and C (3 marks)
State THREE differences between mitosis and meiosis. (3 marks)
Name the process during which the exchange of genetic materials occur at prophase 1
of meiosis. (1 mark)

4) The diagram below indicates an organism that grows under shaded places with damp
conditions. Study it and answer the questions that follow.
 (a) Name the division to which the specimen belongs. (1 mark)
(b)Name and state the functions of the parts labeled Q, R and S. (6 marks)
Name the two body forms of the organism in its alternation of generation. (2 marks)
5) a) Explain how the following meristematic tissues contribute to growth of
higher plants
i) Vascular cambium (2marks)
ii) Cork Cambium (2marks)
The diagram below shows a life cycle of a cockroach

Name the hormone that would be at high concentration during.

 First week (1mark)
Second week (1mark)
Name the structure that produces hormone in a (ii) above (1 marks)
Name the series of stages through which the nymph undergoes to reach adult stage
(1 marks)
SECTION B:(40 MARKS)
Answer question 6 (Compulsory) and EITHER question 7 or 8
6) An experiment was carried out in which red blood cells were put in salt solutions of
different concentrations. The table below shows the percentage of cells which
were destroyed by haemolysis in different salt concentration.

Salt concentration % of RBC destroyed

(g/dm³) By haemolysis
0 100
1 100
2 100
2.5 100
3.0 100
3.5 96
3.7 80
4.0 60
4.5 16
4.7 0
5.0 0
6.0 0
(a) Draw a graph of percentage of red blood cells haemolysed against
salt concentration. (6 marks)
(b)Explain haemolysis of red blood cells. (3 marks)
(c) From the graph, state:
(i) the salt concentration at which 50% red blood cells were haemolysed. (1 mark)
(ii)the highest salt concentration when the largest number of red blood cells were
haemolysed. (1 mark)
(d) (i) Suggest the normal salt concentration in the blood of the mammal from
which the red blood cells were obtained. (2 marks)
(ii)Give a reason for your answer in (d) (i) above. (1 mark)
 What term is used to describe the solution with equal solute concentration as that of the
cells (1 mark)
(e) Name the process in the human body that ensures that haemolysis of red blood cells is
prevented. (1
mark)
(f) State four roles of osmosis in organisms. (4 marks)

7. Describe the role of hormones in the mammalian female reproductive cycle. (20 mks)

8. Describe the

(i) Process of inhalation in mammals (10 marks)

(ii) Mechanism of opening and closing of stomata (10 marks)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 6
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer 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.

Housefly (1 mk)
Scorpion (1 mk)
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)
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)
Distinguish between natural immunity and acquired immunity. (1mk)
Identify one immunizable disease in Kenya. (1mk)
7) (a) State two adaptations of the alveolus to its functions. (2mks)
Suggest a reason for asthmatic patient producing a wheezing sound during breathing?
(1mk)
 What is the significance of the cartilage found in the human trachea being incomplete
(c- shaped rings) (1mk)
8) Define the following terms;
 a. Inter specific competition. (1mk)
b. 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)
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?
Of the complementary strand? (1mk)
On a m- RNA strand copied (1mk)

11) The paddles of whales and the fins of fish adapt these organisms to aquatic habitats.

Name the evolutionary process that may have given rise to these structures. (1mk)
What is the name given to such structures? (1mk)
Give two examples of vestigial organs in man. (2mks)
12) Name the organelles that carry out the following functions
(4mks)
Destroy old and worn-out organelles
Formation of spindle fibres
Osmoregulation
Selective passage of substances into the cell

13) (a) Why would you give an athlete glucose and not sucrose after a race?
(1mk)
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)

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

a.

(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

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

b. (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.

What happens to the temperature of each organism as the external temperature increases.
(2 mks)
Human –
Snake
b)Humans are described as homoithermic. State the advantage of this condition.
(2mks)
21) .
a)State three differences between light stage and dark stage of photosynthesis. (3 mks)
22) Define;
Pulmonary circulation (1mk)
Systemic circulation (1mk)
23) .
The diagram below represents a plant cell that was subjected to a certain treatment.

(a) At the start At the end of the experiment

Account for the shape of the cell at the end of the experiment. (2
mks) 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.
Cutting thin sections. (2 mk)
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

a. With a reason identify the stage.

i. Stage (1 mk)
ii. Reason (1 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)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 6
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) Study the diagram below and answer the questions that follow

Identify the structure (1mks)

State the role of the part labeled R (1mk)
A student took a meal of lean meat. Briefly describe the digestion of the food
 substance where this structure is found (3mks)
What is the role of the following: enterokinase and cholecystokinin in digestion? (2mk)
Enterokinase.
 Cholecystokinin…………………………………………………………………………
State the deficiency disease associated with lack of vitamin B2 (1mk)
2) The diagram below shows how gaseous exchange occurs across the gills in fish.

i Name the type of flow shown above (1mk)

ii Explain the advantage of the above flow named in a(i) above. (1mk)

If the fish is removed from water it dies immediately. Explain why (2mks)
c) Explain mechanism of gaseous exchange in frog through the skin (4mks)

3) A freshly obtained stem from herbaceous measuring 4cm long was split lengthwise to
obtain two similar pieces. The pieces were placed in two different solutions of different
concentrations in petri dishes (l1 and L2) for 30 minutes. The appearance after 30
minutes is as shown.

State the type of solutions in which L1 and L2 was placed (2mks)

Account for the appearance of the pieces in solutions L1 and L2 (4mks)
State two significance of the biological process involved in the experiment.(2mks)
4) .The diagram below shows structures of the bat wing and human arm.

Wing membrane

These structures are thought to have same ancestral origin. State one structural similarity
and one adaptation difference between the two.
i) Structural similarity. (1mk)
ii) Adaptation difference. (2mks)
(b)Give two other examples of structures in nature that show the type of evolution as in
(a) above. (2mks)
(c) Distinguish between the erms ‘chemical evolution’ and ‘organic evolution’. (2mks)
(d) What is the study of fossils called? (1mk)

5) 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.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)
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)
SECTION B (40MKS)
Answer question 6 (compulsory) and either question 7 or 8
6) An experiment was carried out to investigate the effects of hormones on growth of
lateral buds of three pea plants. The shoots were treated as follows; Shoot A – Apical
bud was removed Shoot B – Apical bud was removed and gibberellic acid placed on
the cut shoot.

Shoot C - Apical bud was left intact.

The length of branches developed from lateral buds was determined at regular intervals.
The results obtained are as shown in the table below:
 TIME IN DAYS SHOOT A SHOOT B SHOOT C
0 3 3 3
2 10 12 3
4 28 48 8
6 50 90 14
8 80 120 20
10 118 152 26
(a) Using the same axes, draw graphs to show length of branches against time. (8mks)
(b) (i) What was the length of the branch in Shoot B on the 7th day? (1mk)
(ii)What would be the expected length of the branch developing from Shoot A on the 9th
day? (1mk)
(c) Account for the result obtained in the experiment. (6mks)
(d) Why was Shoot C included in the experiment? (1mk)
(e) What is the importance of gibberellic acid in Agriculture? (1mk)
(f) State two physiological processes that are brought about by the application of
gibberellic acid on plants. (2mks)

7(a) Describe the process of fertilization in a flowering plant. (14mks)

(b) State the changes that take place in a flower after fertilization. (6mks)

8 Describe the structural adaptation of the mammalian heart to its functions (20mks)
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 7
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. a) Name the causative agents of the following diseases in humans.
i) Typhoid. (1mk)
ii) Amoebic dysentery. (1mk)
2. State the function of the following cell organelles.
i) Ribosome. (1mk)
ii) Lysosomes (1mk)
iii) Nucleolus. (1mk)
3. a) Name one defect of the circulatory system in humans. (1mk)
b) State three functions of blood other than transport. (3mks)
4. a) Distinguish between epigael and hypogeal germination in plants. (2mks)
b) Name the gland that secretes the following hormones. (2mks)
i) Ecdysone
ii) Juvenile
5. a) Give two sex linked genes found on the Y-chromosome. (2mks)
b) Below is a nucleotide strand
A A G T C
i) Identify the type of nucleic acid. (1mk)

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999 000
 ii) Give a reason for your answer in (a) above. (1mk)
6. a) Distinguish between homologous and analogous structures. (2mks)
b) Give one reason why organisms become resistant to drugs. (1mk)
7. The following specimen was extracted from a newly discovered organism.

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999 000
 Q

a) Name the tooth labeled M. (1mk)

b) Name the part labeled Q and state its role. (2mks)
Name………………………………………………..…………………….
Role
8. The diagram below represents a cell organelle

a) Name the part labeled Y. (1mk)

b) State the function of the part labeled X. (1mk)
c) Explain how dark stage of photosynthesis is dependent on the light stage. (2mks)
9. a) Name two gaseous exchange surfaces in plants. (2mks)
b) What is the importance counter current flow system in fish? (2mks)
2
10.Form three students wanted to estimate the population in 5km grass field near a school
compound. They captured 36 grass hoppers and marked them before returning them
to the field. After a few days they made another catch of grasshoppers. They collected
45 grasshoppers out of which only 4 had marks.
a) Name the method of population estimation the students used. (1mk)
b) State two assumptions that were made by the students during the study. (2mks)
c) From the data, calculate the population size of grasshopper. (2mks)
11.State the functions of the following parts. (2mks)
i) a) Endometrium
b) Epididymis
ii) What mechanism facilities the movement of the ovum towards uterus. (1mk)

12.The diagram below represents the flow of energy in a food chain.

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Page 64
 Sun Grass Antelope Leopard Bacteria P

a) Suggest a reason why the energy labeled P does not enter food chain (1mk)

b) State one way in which energy is lost from the food chain. (1mk)

13.The diagram below represents the cross section of a part of a certain plant.

a) Name the class of the plant from which the section was taken. (1mk)
b) Give a reason for your answer in a) above. (1mk)
c) Name the parts labeled A and B. (2mks)
14. State two reasons why the study of biology is important. (2mks)
15.State the economic importance of the following plants excretory procedures. (3mks)
a) Caffeine
b) Quinine
c) Colchicine
16. Define the following terms
a) Irritability (1mk)
b) Stimulus (1mk)
17.A process that occurs in plants is replaced by the equation below
C6H12O6 2C2H5OH+ CO2 + Energy

a) Name the process. (1mk)

b) State the importance of the process named in a) above. (2mks)
18.a) What is Binomial Nomenclature? (1mk)
b) State two rules that are followed when printing scientific names. (2mks)
19.Name three strengthening tissues in dicotyledonous plants. (3mks)
20.Name the site for gaseous exchange in insects. (1mk)
21.a) What is alternation of generations (2mks)
b) Explain why leaves of Peridophytes are referred to as Fronds. (1mk)

22.State four adaptations of red blood cells to its functions. (4mks)

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23. The experiment illustrated below was set up to investigate a certain
physiological process
String

Iodine solution
Beaker Starch solution

Visking tubing

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

b) State the observations that were made after at the end of the experiment
(i) Inside the Visking tubing (1mk)
(ii) Outside the Visking tubing (1mk)
c) Account for the observations in b) above. (2mks)
24.State the differences between the following structures in wind and insect pollinated
flowers. (3mks)
(i) Anther
(ii) Pollen grains
(iii) Stigma
25.A student placed a drop of pond water in a cavity slide and observed it under
the microscope. The student observed many fast moving organisms, one of
which is represented in the diagram below.
p

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

b) Name the structures labeled P and N (2mks)
26.A person was found to pass out large volumes of dilute urine frequently. Name the;
a) Disease the person was suffering from (1mk)
b) Hormone that was deficient (1mk)

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Page 66
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 7
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. The diagram below shows a section through the mammalian skin

(a) Name the parts labelled W and X (2mks)

(b) State the function of the parts labelled Y and Z (2mks)
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(c) Explain the changes that occur in the skin when it is cold (4mks)

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Page 68
2. (a) Eye colour in fruits flies is sex-linked. Red eye colour R is dominant to white
eye colour r
A heterozygous red –eyed female fly was crossed with a white eyed male
(i) Show the parental genotypes (1mk)
(ii) By means of a genetic cross, determine the genotypic ratio of the offsprings
(4mks)
(iii) Explain why the actual phenotype ratio obtained from this cross could
differ from the
Expected (1mk)
(b) Name two disorders due to non-disjuction (2mks)
3. The diagram below represents a feeding relationship in an ecosystem.

Snakes

Frogs Hawks

Zooplanktons small fish

Snails

Phytoplanktons

(a) Name the type of ecosystem represented by the above food web (1mk)
(b) Name the organism in the food web that
(i) Is a producer (1mk)
(ii) Occupies the highest tropic level. (1mk)
(c) (i) Write a food chain that ends with the hawk as a quarternary consumer.
(1mk)
(ii) State two short terms effects on the above ecosystem if all the small fish were
killed (2mks)
(d) (i) How does oil spills lead to death of fish? (1mk)
(ii) Name one other cause of water pollution apart from oil spills. (1mk)

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4. The experiment below was set – up to investigate some physiological processes.
The glucose solution was first boiled then cooled. The set up was left for 24 hours

(a) Suggest two aims of the experiment. (2mks)

(b) (i) State the expected observations after 24 hours (2mks)
(ii) Explain your observations in a (i) above (2mks)
(iii) Why was glucose solution boiled then cooled? (1mk)
(c) Suggest a control for the above experiment. (1mk)
5. 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 some time, the students observed that the level of sugar solution had risen

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Page 70
(a) What physiological process was being investigated. (1mk)
(b) Account for the rise in the level of sugar solution in this experiment. (4mks)
(c) (i) State the results that the students would obtain if they repeated the experiment using
a piece of boiled pawpaw. (1mk)
(ii) Give a reason for your answer (2mks)

SECTION B (40 MARKS)

Answer questions 6 (compulsory) and either questions 7 or 8
6. During germination and growth of a cereal, the dry weight of endosperm, the embryo
and the total dry weight were determined at two day intervals. The results are shown
in the table below:
a) Using the same axes, draw graphs of dry weight of endosperm, embryo and the total
dry weight against time. (7mks)
Time after planting Dry weight of Dry weight of Total dry
(days) endosperm (mg) embryo (mg) weight (mg)
0 43 2 45
2 40 2 42
4 33 7 40
6 20 17 37
8 10 25 35
10 6 33 39
b) What was the total dry weight on day 5 (1mark)
c) Account for
i. Decrease in dry weight of endosperm from 0 to 10 (2mks)
ii. Increase in dry weight of embryo from day 0 to day 10 (2mks)
iii. Decrease in total dry weight from day 0 to day 8 (1mk)
iv. Increase in total dry weight after day 8 (1mk)
d) State two factors within the seed and two outside the seed that cause dormancy
i. Within the seed. (2mks)
ii. Outside the seed (2marks)
e) Give two characteristics of meristematic cells (2mks)

7. (a) Describe the process of fertilization in flowering plants (15mks)

(b) State the changes that take place in a flower after fertilization (5mks)

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8.(a) Describe the mechanism of inhalation in man. (10mks)
(b)Using photosynthesis theory explain the mechanics of opening of stomata.(10ms)

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 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 8
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) Define the term Entomology. (1mk)
2) What is meant by the term Natural Selection. (2mks)
3) The diagram below shows regions of a root-tip

What is the function of the part labeled K. (1mk)

Name the region labeled L. (1mk)
Give ONE characteristics of the cells in the part labeled Q. (1mks)

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4) The organelle below is important in the process of Nutrition.

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Identify the organelle. (1mk)
Name the part labeled C. (1mk)
Identify the structure within the organelle that would make the leaf to be variegated.
(1mk)
5) A Rhinocerous in a game park was found to be infested with ticks. State the trophic
leveloccupied by Ticks (2mks)
6) State the causative agent of the following diseases. (2mks)
a) Typhoid
b) Pneumonia
7) A student estimating a cell size of an onion epidermal cells observed the following on
a. The microscope field of view using a transparent ruler.

b. The student identified 20 cells across the field of view. Calculate the size of the
cell in
c. Micrometers (show your working) (3mks)
8) Name the tissues whose cells are thickened with:
Cellulose and pectin........................................................................................(1mk)
Lignin................................................................................................................(1mk)

9) The diagram below represents a fern.

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 a) Name Parts labeled A and B. (2mk)
b) To which division does the plant belong? (1mk)
10) Explain how the following factors hinder self-pollination in plants:
a) Protogyny (1mk)
b) Dioecism (1mk)
11) Explain the likely effect on humans and other organisms of untreated sewage
discharged into water body that supplies water for domestic use. (3mk)
12) State TWO differences between osmosis and active transport. (2mk)
13) The diagram below illustrates part of a nephron from a mammalian kidney.

Name the fluid found in the part labeled Q. (1mk)

Identify the process responsible for the formation of the fluid named in (a) above.
(1mk)

Which two hormones exert their effect in the nephron? (2mk)

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14) State TWO characteristics of members of kingdom Monera that are not found in
other kingdoms (2mk)
15) What is meant by the following biological terms?
Crenation (1mk)
Haemolysis (1mk)

16) The diagram below shows a stage during fertilization in flowering plant.

i.
Name the parts labeled Q, R, and S. (3 mk)

State the function of the pollen tube. (1 mk)

17) An experiment was set to investigate a certain aspect of response. A seedling was
put on a horizontal position as shown in figure M below. After 24 hours, the set up
was as shown in figure N.

M N
a) Name the response exhibited. (1mk)
b) Explain the curvature of the shoot upwards. (3mk
18) The paddles of whales and the fins of fish adapt these organisms to aquatic
habitats.

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Page 77
Name the evolutionary process that may have given rise to these structures. (1mk)
What is the name given to such structures? (1mk)
Give ONE examples of vestigial organs in man. (1mk)
19) A group of Form four students set up an experiment to investigate a biological process
using termites. They used a small box in which a portion was covered with black paper and
had moist soil. The open part had dry soil. Termites were placed inside in open area of the
box.
card

board

Black Dark area Lit area

paper Dry

soil
Moist soil Termites

Predict what happened to the termites after 30 minutes. (1mk)

What form of response is exhibited by termites? (1mk)

State one biological significance of the above response to termites.(1mk)
20) The diagram below represents an experimental set up to investigate a certain
scientific concept. The potted plant was first destarched by keeping it in dark for
four days.

The set up was then placed in sunlight for five hours and leaves were tested for starch.
What scientific concept was being investigated? (1mk

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i) Give the results likely to be obtained after starch test for A and B.

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 a) A and B.
ii. A......................................................................................(1mk)
iii. B.................................................................................(1mk)
iv. ii) Account for the results in leaf A in b (i) above. (1mk)
Why was leaf C included in the set-up? (1mk)
21) Explain why a pregnant woman excretes less urea compared to a woman who is
not- pregnant. (2mk)
22) a) Outline the main features of Lamarckian theory of evolution. (2mk)
In view of modern genetics, explain why Lamarck’s theory is unacceptable. (1mk)
Name one factor in nature that increases the process of evolution. (1mk)

23) Explain why fresh water Protozoa like amoeba do not burst when placed in distilled
water. (2mks)
24) The equation below shows an oxidation reaction of flow food substance
5C51H98O6 + 145O2 102CO2 + 98H2O + Energy
Determine respiratory quotient of the oxidation of the food substance above.(2mks
Identify the food substance (1mk)
25) Give the one aspect of dichogamy in flowers (1mk)
26) The table below shows the concentration of important plant nutrients
Ion Concentration in pond Concentration in cell
water (ppm) sap (ppm)
Chloride 200 50
Potassium 1 15

a. Name the process by which the above ions could have been taken up by the
plants
Potassium......................................................................................(1mk)
Chloride..........................................................................................(1mk)
27) In an experiment Drosophila melanogaster (fruit flies) with broad abdomens were
crossed with those having narrow abdomens. All the offspring (F1 generation) from
the crosses had broad abdomens. Using A to denote the genes for abdomen size,
Give the genotypes of the parents (2mks)
If 150 fruit flies had narrow abdomens in the second filial generation (F2)
how many fruit flies with broad abdomens were in the same generation (show
your working) (2mks)

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28) Give a reason why two species in an ecosystem cannot occupy the same niche.
(1mk)
29) A person was found to pass out large volume of dilute urine frequently. Name the:
Disease the person was suffering from? (1mk)
Hormone that was deficient (1mk)
30) Identify the processes X and Y and the unknown product Z in the chemical
equations below;
[i] Glucose + Galactose X Lactose + Z (2mks)

[ii] G + water Y Glucose + Fructose (2mks)

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Page 81
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 8
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) The diagram below shows a set up to investigate a factor necessary for germination.

Name the factor under investigation. (1mk)

State the role of pyrogallic acid in the set up. (1mk)
Which type of respiration is taking place in the beans? (1mk)
Write a word equation for the process named in (c) above. (1mk)
Explain why plants can only carry out the above respiration process for a short while.
(1mk)
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State other three factors necessary for germination. (3mks)

2) a) Birds have beaks which are structurally modified to different modes of feeding.

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What is the name given to such structures in evolution? (1 mark)
What is the name given to the evolution of beaks of birds? (1 mark)
What is meant by “vestigial structures”? (1 mark)
Name two vestigial structures present in man. (1 mark)
Bacteria tend to develop resistance to antibiotics after they have been subjected to them
for a long period of time. Explain. (2 marks)
Explain continental drift as an evidence of evolution. (2 marks)

3) What is internal fertilization ? (1mk)

Suggest two disadvantages of internal fertilization in most mammals. (2mks)
State two roles of placenta in mammals. (2mks)
Mention one role played by each of the following hormones in human menstrual
cycle.
Oestrogen
Luteinizing hormone.
Follicle stimulating hormone (3mks)

4) Below is a cell obtained from a living organisms. Study it and answer the questions
that follow

A
E

From which kingdom of organism was the cell obtained? ( 1mk)

Give two reasons for your answer in 4 (a) above (2mks)

On the diagram identify parts A,B and C. (3mks)

State the role of parts D and E. (2mks)

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5) a) What is meant by the term linked genes? (1mk)

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Haemophilia is a genetic condition transmitted through a recessive gene linked to X
chromosome. The normal gene may be represented by XH.
What is the genotype of a haemophilic female? (1mk)
A woman who is a carrier for the haemophilia gene marries a normal man. Work
out the phenotypic ratio for their offspring. (4mk)
Haemophilia is more common in males than in females. Explain this phenomenon.
(2mks)

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 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 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 the
observation. (3mks)
(d) Account for the observation made on the amount of urine produced as the temperature
increases (3Mks)
(e) (i) How is the kidney adapted to its function (4mks)
(ii) Differentiate between excretion and egestion. (2mks)
7. Explain how the following organisms are adapted to their mode of feeding
(a) Herbivores (10mks)
. (b) Carnivores (10mks)
8. (a) (i) State two significances of transpiration. (2mks)
(ii Discuss the forces involved in movements of water from roots to the leaves (8mks)
(b) Describe the mechanism of opening and closing of stomata using photosynthetic
theory (10mks)

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Page 86
 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 9
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1) State two features of leaves which enable a plant to reduce the loss of water. (2mk)
2) a) State the Phylum where all members have open circulatory system. (1mk)
Explain two advantages of closed circulatory system over open circulatory system.
(2mk)
3) 3. a) Under which of the following magnifications would one see a larger part of the
specimen X 40 or X500? Give a reason. (2 Marks)
(b) State how magnification is worked out in a light microscope. (1 Mark)
4) .Name two components of blood that are not present in glomerular filtrate. (2mks)
5) The following is an equation representing a type of
respiration C6H12O6 2C3H6O3 + Energy
Identify the type of respiration. (1mk)
a) Suggest one industrial application of the process named in (a) above. (1mk)
6) 6a) What is meant by the term binomial nomenclature. (1mk)
A dog is called Canis familiairis. Name the taxonomic unit represented by canis.(1mk)
7) .Give two functions of the exoskeleton in arthropods. (2mks)
8) The colour of tips of hair in Shepherd dog is controlled by a gene with three alleles B
for Black, R for red and C for copper. A cross between pure breeding red and copper
hair tips produce offsprings with scarlet hair tips. Crossing pure breeding red and black
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Page 87
hair tips yields all red offsprings. A cross between pure breeds of copper and black
produce offsprings that are all copper.
a) Comment on the inheritance of the three alleles B, R and C. (2 marks)

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Page 88
 b) A dog breeder wishes to know the genotype of a dog with red hair tips. State and
explain the cross needed to determine the dog’s genotype. (2 marks)
9) . What is the importance of seed dispersal? (3mks)
10) State two adaptations of guard cells to its function. (2Marks)
11) Describe the censor mechanism of seed dispersal. (2mks)
12) Explain “struggle for existence” and “survival of the fittest” as they apply to
natural Selection. (4mks)
Struggle for existence
Survival of the fittest:-
13) (a) Define the following term
Incomplete metamorphosis. (1mk)
(b) State one function of each of the following hormones (2mks)
a. Juvenile hormone.
b. Ecdysone.
14) a) Name the organelle where the cell wall components are synthesized. (1mk)
b) State two roles of cell wall to a plant. (2mks)
15) The diagram below represents a section through the mammalian ear.
T

Q R S
a) Name the structures labelled R and T. (2 mark)
b) State how the structures Q and S are adapted to their functions. (2 mark)

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16) The diagram below represents some gaseous exchange structures in humans

(a) Name the structures labeled K ( 1 marks)

(b) state two way in which the structure labeled J is suited to its function? (2 marks)
Name the process by which inhaled air moves from the structure labeled L into
blood capillaries ( 1 mark)
Give the scientific name of the organism that causes tuberculosis in humans
(1 mark)
17) The diagram below represents the anterior view of a certain vertebra.
A

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 (a) With a reason, identify the type of vertebra shown above. (1mks)
Name the parts labeled.
(i) A (1mk)
(ii) D (1mk)
c) State the function of part E. (1mk)
18) State THREE adaptations of a leaf to gaseous exchange. (3 marks)
19) What is the importance of the pollen tube in fertilization in plants? (1 marks)
20) .The following are events suggested by the theory of natural
selection. Reproduction of organism with favorable variation
The emergence of new
species Variation between
individuals A struggle for
existence
The survival to the fittest
Who postulated the theory of natural selection? (1 mark)
What is meant by natural selection? (1 mark)
Arrange in an order that best illustrate the sequence of events leading to evolution
by natural selection (1 mark)

21) .The diagram below shows a vertical section through human brain.

Name the part labeled K (1 mark)

State why the part labeled J is large and highly folded. (1 mark)
Give a letter on the diagram which:

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Serve as endocrine gland (1 mark)

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 Control breathing, swallowing and blood circulation (1 mark)
22) The diagram below shows part of a nephron from the human kidney.

(i) Name the structure labelled R. (1 mark)

(ii) Name the process carried out at P (1 mark)
The hormone ADH affects water reabsorption from the nephron.
Which part of the brain releases ADH? (1 mark)
Name a part of the nephron where water is reabsorbed. (1 mark)
23) .The figure below illustrates a food web in a certain ecosystem.

From the food web:

Draw the shortest food chain; (1mk)

identify the organisms with the highest
Number of predators (1mk)
Biomass (1mk)

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24) .The diagram below represents a certain organism collected by a student at the
sea shore.

(a) Name the class to which the organism belongs. (1mk)

(b) Give three reasons for your answer in (a) above. (3mks) -
25) In an experiment, disinfection soaked bean seeds were put in a vacuum flask
which was then fitted with a thermometer as shown in the diagram below.

The temperature readings were taken every morning for three consecutive days.
Which process was being investigated? (1 mark)
i) what were the expected results? (1 mark)
ii) Account for the answer in (b) (i) above? (2 marks)

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26) The diagram below shows a specialized plant cell

(a) i) name the cell (1mk)

ii) name the cell parts labeled D and E (2mk)
b) state the functions of the part labelled C (1mk)

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 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 9
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. An investigation was carried out to study the effects of the concentration of sucrose
solutions on pieces of tulip stem 44mm in length. The pieces were placed in
different concentrations of sucrose solutions and measured after two hours of
immersion. The results are shown in the table below.

Sucrose 0.2 0.3 0.4 0.5 0.6 0.7 0.8

concentration
(moles per
litre)
Length after 2 50 48 46 44 42 42 42
hours (mm)

a. Explain the effect of the 0.2 moles per litre sucrose solution on the length
of the pieces of the tulip stem. (3mks).
b. Use information from the table to predict the concentration of a sucrose
solution isotonic to the cells in the tulip stem. (1mk).
c. (i) Give the term which would be used to describe the cells in the tulip stem

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after immersion in a solution with a sucrose concentration of 0.7 moles per
litre. (1mk)

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 ii. Draw the appearance of a cell from the tulip stem after immersion in a
solution with a sucrose concentration of 0.7 moles per litre. (2mks).
d. State one role of the process being investigated in plants. (1mk)

2. Below is a diagram of a sperm cell.

(a) Identify parts labeled X and Y. (2 marks)

X
Y
(b)Explain how parts W and Z adapt the cell to its function. (4 marks)
W
Z
(c) Using letter P identify or label on the diagram the part of the cell rich in DNA.
(1 mark)
(d)State the function of part X. (1 mark)

3. Polydactyl is a genetic disorder in which people inherit an extra digit. Polydactyl is

caused by a dominant allele (B). The table below describes the different genotypes
for polydactyl.
a) Complete the table below by giving the correct genotype, alleles of each
genotype and the expected number of fingers per hand. (4mks)
Genotype Alleles Expected number of digits per hand.
Homozygous dominant Six
bb
Heterozygous. Bb

b) The table below shows results of marriages between various parents. Complete
the table by writing the probability of each marriage producing a child with
polydactyl. One has been done for you. (2mks)

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 Parental genotypes. Probability of child with
polydactyl
Bb X BB
Bb X bb 0.5
Bb X Bb

c) State the two types of variation (2mks)

3. Cuban pond weed (Elodea cubiensis) is a common water plant that produces tiny air
bubbles of oxygen during photosynthesis. The number of bubbles produced per
minute indicates the rate of photosynthesis. The graph shows how the rate of
photosynthesis in the pond weed relates to light intensity.

a). write the equation to account for the air bubbles. (1mk)
b). Name the factor that affects photosynthesis at point A. Explain. (2mks)
c). Explain why the rate of photosynthesis does not increase any further at high light
intensity.(point B) (2mks)
d). Explain the role of the following in photosynthesis.
i) Chlorophyll. (1mk)

ii) Water. (1mk)

e). Name one product of the light stage of photosynthesis used in the dark stage of
photosynthesis. (1mk)

5. Study the diagram below and answer the questions that follow.

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 a) Name the part labeled A and B (2marks)
b) State the function of the part labeled C (2marks)
c) How is he part labeled E adapted to its function (2marks)
d) Identify the structure that perform the same function as one illustrated above in
(2marks)
i) Amoeba

ii) Fish
SECTION B (40 Marks)
Answer question 6 (compulsory) and either questions 7 or 8

6. In an ecological study a certain insect population and that of predators was estimated
in a certain grassland over a period of one year.
Month Jan Feb March April May June July Aug Sep Oct Nov Dec
No of insects 10 20 16 24 50 85 45 18 12 30 48 70
No of 10 12 8 10 16 30 10 4 2 2 5 20
predator
Rainfall 20 6 55 350 500 250 12 10 25 190 240 30
amount(mm)

a) Using the information above plot on the same axis the graph of number of insects
and number of predators against time in months. (7mks)
b) Suggest what happens to the insect’s population during dry month. (2mks)
c) Explain the relationship between the insect population and that of the predators.
(3mks)
d) Suggest what happens to the predator’s population during the dry month. (2mks)
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 Name the trophic level occupied by (3mks)
i) Predator.
ii) Insect.
iii) Grass.

e) Name the method used to estimate population of (3mks)

i). Predator.
ii. Insect.
iii. Grass.

7. State and explain various areas where knowledge about genetics is applied.(20mks)

8. a) Describe the process of fertilization in flowering plant. (15mks)

b) State the changes that take place in a flower after fertilization. (5mks)

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 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 10
BIOLOGY
PAPER 1

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. a. Name the external feature which is common in birds, fish and reptiles (1mk)
b. State two characteristics of fungi (2mks)
2. State the functions of the following parts of a light microscope (2mks)
a. Objective lens
b. Diaphragm
3. a. Define the term seed dormancy
b.The diagram below represents a stage during germination of a seed

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4. a. State two causes of chromosomal mutations (2mks)

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 b.Distinguish between continuous variation and discontinuous variations (2mks)
5. The diagram below shows a section through a plant organ

a. i. Name the class of the plant which the section was obtained (1mk)
ii. Give a reason for your answer in (a) (i) above (1mk)
b. State the functions of the part labeled F (1mk)
6. State the function of the following cell organelles \
a. Ribosome (1mk)
b. Lysosomes (1mk)
7. a. Pregnancies continues if the ovary of an expectant mother is removed after 4 months
explain (2mks)
b.What is the role of the testes in the mammalian reproductive systems (2mks)
8. In an experiment the shoot tip of a young tomato plant was decapitated as shown in
the diagram below

a. State the expected results after 2 weeks (1mk)

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 b. Give a reason for your answer in (a) above (2mks)
9. a. Distinguish between diffusion and active transport (2mks)
b.State one role that is played by osmosis in (2mks)
i. Plants
ii. Animals
10.a. Name the gaseous exchange surface in insects (1mk)
b.How is the surface named in (a) above suited to its function
11. Explain why plants do not require specialized excretory organs (2mks)
12.Explain how the following factors affect the rate of photosynthesis
a. Concentration of carbon (iv) oxide (1mk)
b. Light intensity (1mk)
13. Explain what happens in human when concentration of glucose in the blood decreases
below the normal level (4mks)
14. Explain how the carnassial teeth of a dog are adapted to their function (2mks)

15.a. State three structural differences between arteries and veins in mammals (2mks)
b.Name a disease that causes thickening and hardening of arteries (1mk)
16.from the equation given below, calculate the respiratory quotient (RQ)
2C51H98O6+145O2 102CO2 + 98H2O +Energy
Show your working (2mks)
b.Identify the substrate respired in the above equation (1mk)
17.a. What is fertilization (1mk)
b.Explain how double fertilization takes place in plants (2mks)
18.In an experiment, the pituitary gland of a rat was removed
state the effect this will have on the quantity of urine produced by the rat (1mk)
19.The diagram below show part of a food relationship in an ecosystem

a. Name the food relationship shown in the diagram (1mk)

b. Name the trophic level occupied by organism A (1mk)
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 c. What is the main source of energy in the ecosystem shown in the diagram above
(1mk)
20. Other than transport. State two other function of mammalian blood (2mks)
21.Below is a nucleic acid stand
A G U C A C G

a. name the nucleic acid (1mk)

b. give a reason for your answer in (a) above (1mk)
22.Name two structures of gaseous exchange in aquatic plants (2mks)
23.What is the significance of chiasma formation during meiotic cell division (1mk)\
24.Define the term evolution (1mk)
b.Give two evidence of organic evolution (2mks)
25.Identify the stage of cell division below (1mk)

26. State two characteristics of cells found at the apical meristems (2mks)
27.The diagram below represents a mature fruit of a certain plant

a. State the agent dispersal for the fruit .(1mk)

b. Give a reason for your answer in (a) above (1mk)
c. State two other characteristics of fruit and seed dispersal by the agent named in (a)
above (2mks)
28. Explain how the following adaptations will reduce the rate of transpiration (2mks)
i. Sunken stomata

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 ii. Leaf folding
29. Name the disease caused by each of the following microorganism (2mks)
i. Plasmodium falciparum
ii. Entamoeba histolytica
30. State two properties of monosaccharaides (2mks)

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 KCSE 2024 TOP-SCHOOLS’ MOCKS
MOCK TRIAL 10
BIOLOGY
PAPER 2

TIME: 2 HOURS

NAME………………………………………………………………………
……………….

SCHOOL………………………………………………

SIGN………………………….

INDEX NO……………………………………………. ADM

NO……………………..

Answer All the Questions

1. Study the flow chart below of a process that takes place in both plants and animals.

a) Name the above process. (1mk)

b) i) In the above process name the chemical reaction represented by X. (1mark)
ii) Name the part of the cell where the enzyme controlled reactions in b(i) above
takes place. (1mark)
c) Name the products Z in
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i) Plants…………………………………………. (1mark)
ii) Animals………………………………………… (1mark)

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 d)What would be the fate of pyruvic acid if oxygen supply is availed in
the mitochondria of an animal cell (2marks)
(e) Define the term oxygen debt (1mark)
2. .In a certain bird species red flight feathers is controlled by gene R while white
flight feather is controlled by gene r. The heterozygous condition Rr results into pink
flight feathers.
(a) Using a punnet square, find the genotype of a cross between pink flight feathered
bird and white flight feathered bird. (4 marks)
(b) Which type of dominance is illustrated here? (1 mark)
(c) i) Identify the nuclei acid whose base sequence is shown below. (1 mark)
G- A - C - U- A - G - C - G-U
(ii)Give a reason for your answer in (i) above (1 mark)
(iii) If this nucleic acid was involved in protein synthesis, how many amino acid
would be present in the protein synthesized. (1 mark)
3 .The diagram below represents a longitudinal section through the ileum wall.

a) Identify the structures labeled X and Y (2 marks)

b) State one function of X and Y (2 marks)
c) State two functions of the ileum (2 marks)
d) Explain the role of the liver in digestion (1 mark)
e) State the endocrine (hormonal) role of pancreas in a mammal (1 mark)

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4. The diagram below represents the female reproductive system.

C
A

(a) Name the structures labeled A and C (2 marks)

(b) State the conditions that results if implantation occurs at point labeled D.
(1 marks)
(c) Name the hormone secreted by the part labeled A and for each give one function
(4 marks)
(d) What role does part labeled B play during pregnancy? (1 mark)
5. The diagram below shows some components of a light microscope.

a) Name the parts labeled (2 marks)

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 K
M
b) State the functions of (2 marks)
P
Q
c) A student was viewing a prepared slide of a plant cell under high power
microscope. The features of the cell were blurred. Which one of the labeled parts of
the microscope would the student use to obtain:-
(i) A sharper outline of the features. (1 mark)
(ii) Give the formula used to calculate magnification in a light microscope. (1 mark)
d) A student was preparing a section of a plant cell to be viewed on a light
microscope. Give a reason for each of the following steps:-
(i) Cutting a very thin section…… (1 mark)
(ii) Staining the section.........................................................(1 mark)
(iii) Putting the section in water............................(1 mark)

Answer question 6 (compulsory) and either question 7 or 8

6 During germination and growth of a cereal, the dry weight of the endosperm, the
embryo and total dry weight were determined at two day intervals. The results are
shown in the table below.

Time after Dry weight of Dry weight Total dry weight

planting endosperm (mg) of embryo (mg)
(Days) (mg)
0 43 2 45
2 40 2 42
4 33 7 40
6 20 17 37
8 10 25 35
10 6 33 39
a) On the same axes, draw graphs of dry weight of endosperm, embryo and the total
dry weight against time. (7marks)
b) What was the total dry weight on day 5? …………… (1mark)
c) Account for: i) Decrease in dry weight of endosperm from day 0 to day
10. (2marks)

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 ii) Increase in dry weight of embryo from day 0 to day 10. (2marks)
iii) Decrease in total dry weight from day 0 to day 8. (1mark)
iv) Increase in dry weight after day 8. (1mark)
d) State two factors within the seed and two outside the seed that cause dormancy.
i) Factors within the seed…………………………… (2marks)
ii) Factors outside the seed. …………………………....... (2marks)
e) Give two characteristics of meristematic cells............................................(2marks)

7. Describe how the mammalian skin is adapted to its functions (20 mrks)

8. a) Describe how xerophytes are adapted to living in their habitat. (10 mks)

b) Explain how an upright position is maintained in herbaceous plants. (10 mks)

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 THE END

THIS IS THE 1st SERIES OF TOP

SCHOOLS BIOLOGY MOCK
EXAMINATIONS TRIALS

CALL/TEXT/WHATSAPP

0746 222 000 OR 0742 999 000

mwalimuconsultancy@gmail.com

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 CAUTION TO KCSE
CANDIDATES:

In the event you realize part/all of

these top
national schools mock
questions were directly or
indirectly lifted in the final
KCSE exams, please, do not
panic!

KILA LA HERI

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SUCCESS

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