PREDICTION 2

PAPER 2

SECTION A (40 MARKS)

1.(a) Explain the role of the following organs in the digestion of food in a mammal e.g humans.
(i) Salivary glands (2marks)
….………………………………………………..………………………………………………………
……………………………………………………………………………………………………………
(ii) Pancreas (2marks)
….…………………………………………………………..……………………………………………
……………………………………………………………………………………………………………
(b) Explain how beneficial it is for some herbivores being grazers and others being browsers.
(2marks)
….………………………………………………………………………………………………………………
…………………………………………….…………………………………………………………………….
(c) What is the importance of roughage in the diet (2marks)
….………………………………………………………………………………………………………………
…………………………………………………….……………………………………………………………
……………….……………………………………………………………………………………….…………
2a)The part of one DNA strand molecule was found to have the following base sequence G-C-C-T-A-T-C-
A-C.What is the base sequence of:
i) The complimentary DNA strand. (1mark)
….……………………………………………………………………………………..
ii) m-RNA strand copied from this DNA portion. (1mark)
….……………………………………………………………………………………..
b) In maize the gene for purple colour is dominant to the gene for white colour. A pure breeding maize plant
with purple grains was crossed with a heterozygous plant of the above traits.
i)Using letter G to represent the gene for purple colour,work out the genotypic ratio of the offspring.
(4marks)
….………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
iii) State the phenotypic ratio of the offspring. (1mark)
….………………………………………………………………………………………
c) What is meant by hybrid vigour? (1mark)
….………………………………………………………………………………………………………………
3.A student observed a feeding relationship while on a field study on an island.
⚫ Small fish feed in sea grass.
⚫ Eagles feed on small fish.
⚫ Insect larvae and mollusks feed on sea grass.
⚫ Insect larvae fed on by small fish while crabs feed on insect larvae and mollusks.
a) From the above information construct a food web. (3marks)

b) In which trophic level is mollusks found? (1mark)

….………………………………………………………………………………………
c) Extract a food chain where the eagle is a tertiary consumer. (1mark)
….………………………………………………………………………………………….……………………
d) Suppose all the crabs were poisoned to death ,what would be the immediate effect in the ecosystem? Give
a reason. (2marks)
….………………………………………………………………………………………………………………
e) State any one abiotic factor in an ecosystem. (1mark)
….………………………………………………………………………………………………………………
4.The diagram below illustrates an experiment to demonstrate certain aspect of respiration.

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 A B
a.i. State the aim of experiment. (1mark)

ii. What is the role of soda lime in the set up? (1mark)
………………………………………………………………………………………
iii. State observations made in vessels A and B (2marks)
iv.Account for the observation made in vessel B in (iii) above. (2marks)
….………………………………………………………………………………………………………………
v.Why is it necessary to enclose the pot with polythene bag? (1mark)
…………………………………………………………………………………………
…………….……………………………………………………………………………
b. During aerobic respiration involving lipid as a respiratory substrate, 102 cm3 of carbon (iv) oxide was
produced. Determine the volume of oxygen that was used given that the respiratory quotient(RQ) was 0.71
(1mark)
………………………………………………………………………………………

5. The figure below shows changes that take place during menstrual cycle in human.

(a) Name the hormone whose concentrations are represented by curves F and G (2marks)
F….…………………………………………………………………………………
G….…………………………………………………………………………………
(b) State the effects of the hormones named in (a) above on the lining of the uterus.
(2marks)
….………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
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(c) (i) Name the hormone which is released by the pituitary gland in high concentration on the 14th day of
the menstrual cycle. (1mark)
….……………………………………………………………………………………….
(iii) State two functions of the hormone named in (c) (i) above (2marks)
….………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
(d) Using the above figure, state the fertile period during the menstrual cycle . (1mark)
….………………………………………………………………………………………
SECTION B
Answer question 6(Compulsory) in the spaces provided after each question and either question 7 or 8
in the spaces provided after question 8.
6. In an experiment to account for a certain process in a given species,rate of carbon (IV) oxide gas
consumption and the rate of carbon (IV) oxide gas released were measured over a period of the day.The
results of the investigation are as shown in the table below.
Time of the 6am 8am 10a 12am 2pm 4pm 6pm 8pm 10pm 12am
day m
Carbon (IV) 20 86 138 182 182 100 36 0 0 0
oxide
consumption
I n mm/min

Carbon (IV) 76 44 20 06 06 12 62 96 96 96
oxide
released in
mm/min

a)On the same axis on the grid provided ;plot graphs of volume of carbon (IV) oxide consumed and carbon
(IV) oxide released against time. (7marks)

b) Name a biochemical process responsible for; (2marks)

(i) Carbon (IV) oxide consumption.
….…………………………………………………………………………………….
(ii) Carbon (IV) oxide released.
….…………………………………………………………………………………….
c)Account for the shape of the curve for;
(i) Carbon (IV) oxide consumption. (3marks)
….……………………………………………………………………………………………………………
………………………………………………………………………………………………………………
(iii) Carbon (IV) oxide released. (3marks)
….……………………………………………………………………………………………………………
………………………………………………………………………………………………………………
d)(i) Name the end-products of the light stage in photosynthesis. (3marks)
….………………………………………………………………………………………………………………
……………………………………………………….…………………………………………………………
(ii) Explain how temperature affects the rate of a carbon (IV) oxide consumption in a plant.
(2marks)
….……………………………………………………………………………………………………..………
7(a) State any five functions of blood in mammals. (5marks)
(b)Discuss the adaptations of the mammalian heart to its function. (15marks)
8. a) Describe the process of double fertilization in angiosperms. (15marks)
b) State any five changes in a flower after fertilization. (5marks)

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PREDICTION 3
PAPER 2
1.Study the diagram below and answer questions that follow;

a) Name the structures labelled O and M (2 marks)

O -

M -

b) Identify a letter in the diagram that represents blood with the highest concentration of carbon (iv) oxide
(1 mark)

c) Describe how blood is moved by the heart from blood vessel k to blood vessel J. (3 marks)

d)State two features of blood vessel K (2 marks)

2. The diagram below shows exchange of materials between embryo’s bloodstreams and mother’s blood
stream

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(a) (i) Give the names of the parts labelled E and G
E. (1mark)

G. (1mark)

(ii) Name one substance that is in high concentration in E (1mark

(iii) In which organ does this kind of exchange shown occur? (1mark)

(b) Suggest the biological significance of each of the following

i) Development of the pollen tube in fertilization in plants. (1mark)

ii)Fusion of petals to form funnel-shaped corolla tube in certain flowers. (1mark)

c)Give 2 advantages of cross-pollination over self-pollination. (2marks)

3. Form two students subjected an orange plant growing outside the laboratory to the following;
i) Selected two sized leaves and gently brushed them clean on both sides.
ii) Placed two strips of dry cobalt chloride paper on both sides of each leaf and opposite each other and covered
the cobalt chloride papers with cello tape. They observed the time taken for any colour change to occur
and recorded the following.

Side of leaf Upper epidermis Lower epidermis

Time taken 5 minutes 2 minutes

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Use the above information to answer the following questions.
a.i) What was the aim of the above experiment. (1mark)
………………………………………………………………………………………………………
ii) What was the purpose of brush cleaning the leaf (1mark)
……………………………………………………………………………………………………
iii) What was the role of cello-tape in this experiment? (1mark)

………………………………………………………………………………………………………………………
………………………………………………………………………………………
b.i) What was the original colour of dry cobalt chloride paper. (1mark)

………………………………………………………………………………………………………

ii) What colour change did the students observe? (1mark)

……………………………………………………………………………………………………

c. Explain the difference in time taken for the colour change observed. (3marks)
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
……………………………………………………………………
4a). The diagram below represents a member of kingdom Animalia.

i)Name the phylum to which the organism belong. (1mk)

…………………………………………………………………
ii)Using observable features in the diagram, give three reasons for the answer in 4a (i) above. (3mks)
………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
b. To estimate the population size of crabs in a certain lagoon, traps were laid at random. 400 crabs were caught,
marked and released back into the lagoon on the first day. Four days later, traps were laid again at random. Out
of the 374 crabs caught the second time, 80 were found to have been marked.
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i) Calculate the population size of the crabs in the lagoon. (3mks)

ii)What is the name given to this method of estimating the population size? (1mk)

……………………………………………………………………………………………………
5. The diagram below shows samples of blood obtained from two different persons A and B

(a) What genetic disorder is person B suffering from? (1mark)

............................................................................................................................................................
(b) State one advantage and one disadvantage of the disorder exhibited in person A. (2marks)
…………………………………………………………………………………………………

.............................................................................................................................................
(c) Work out the genotype and phenotypes of the resulting offspring of a marriage between
person A and B. Show your working (5marks)

....................................................................................................................................................................................

SECTION B: 40 Mks: Answer question 6 (compulsory) and either question 7 or 8.

6.An experiment was carried out to investigate the effect of temperature on the rate of reaction catalyzed by an
enzyme. The results are shown in the table below.
Temperature 0c Rate of reaction in mg of
product per unit time
5 0.2
10 0.5
15 0.8
20 1.1
25 1.5
30 2.1
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 35 3.0
40 3.7
45 3.4
50 2.8
55 2.1
60 1.1
(a) On the grid provided draw a graph of rate of reaction against temperature. (7mks)

(b) When was the rate of reaction 2.6 mg of product per unit time? (2 mks)
………………………………………………………………………………………………………

………………………………………………………………………………………………………
(c) Account for the shape of the graph between
(i) 50 C and 400 C (2mks)
……………………………………………………………………………………………………………

………………………………………………………………………………………………
(ii) 450 C and 600C (2mks)
………………………………………………………………………………………………… …..

……………………………………………………………………………………………………..

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 (d) Other than temperature name two ways in which the rate of reaction between 50C and 400C could be
increased. (2mks)
……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

(e) (i) Name one digestive enzymes in the human body which works best in acidic condition (1mk)

……………………………………………………………………………………………………
(ii) How is the acidic condition for the enzyme named in (e) (i) above attained? (2mks)

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………(f) The
acidic conditions in (e) (ii) above is later neutralized(i) Where does the neutralization take place?
(1mk)
………………………………………………………………………………………………………
(ii) Name the substance responsible for neutralization. (1mk)

………………………………………………………………………………
7. Discuss various evidence to support organic evolution (20mrks)
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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PREDICTION 4
PAPER 2
SECTION A
(Answer ALL questions in this section)
1. In a biology lesson, some students obtained a young stem and split it half way along the length as shown
in diagram A. They then placed it in solution Y for two hours before making observations. The results were
as shown in diagram B.

a) What was the nature of solution Y? (1mk)

b) Explain why the stem curved as shown in diagram B. (4mks)
c) State three roles of active transport in organisms. (3mks)

2. (a) In human, premature baldness is controlled by a gene on the Y chromosome. Using B to represent the
gene for baldness, work out a cross between a bald man and his wife. (4 mks)

(b)(i) What is the probability of their daughters being bald? (1 mk)

(ii) Give a reason for your answer. (1 mk)

(c) Name one trait in human beings that is determined by multiple allele (1mk)
(d) Name one genetic disorder affecting the human eye (1mk)
3. The picture below represents an evolutionary phenomenon. Study it and answer the questions below.

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(a) What name is given to the above evolutionary phenomenon? (1 mk)
( b) Account for your observation in pictures A and B Observation (2mks)
Accounting (2 mks)
(c) Explain how continental drift is an evidence for organic evolution (3 mks)
4. The micrographs below is of a tissue showing mitosis. Examine it and answer the questions.
R T

a.) i. Identify the tissue from which the micrographs were obtained (1mark)
ii. Give a reason for your answer in a) i above (1mark)
Name the stages represented by R and T. (2marks)
b.) State two significance of mitosis to an organism. (2 marks)
c.) Name two regions in higher plants where cells actively undergo mitosis (2marks)
5. An analysis was done on the contents of faeces of a cow. The results are as shown in the table below.
Content Percentage

Carbohydrates 12
Proteins 0.8
Fiber 14
Fats 1
(a) Name the other component that makes up the faeces of a cow and give its percentage. (1 mk)

(b) Name the substance that contributes the fiber in the faeces. (1 mk)

(c) Cow faeces are normally used as fertilizer that increases nitrates in the soil.

(i) State the component in the faeces that yield nitrates. (1 mk)

(ii) Describe how the component named in (c)(i) above is converted into nitrates (4 mks)

(d) Explain why the manure would be better if the cows urine was added to the faeces. (2 mks)

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SECTION B (40 Marks)

Answer question 6(Compulsory) and either question 7 or 8 in the spaces provided after question 8.

6.The length of a grasshopper femur and internode of a seedling were recorded in a period of 24 weeks.
The results are recorded in the table below.
Week 1 3 5 7 10 13 16 18 20 24
Average length of femur 8.0 9.0 9.0 9.0 13.0 13.0 15.0 19.0 19.0 19.0
Average length of 5.0 6.5 10.5 16.5 24.5 27.5 32.5 34.5 36.0 37.5
internode(mm)

(a) Plot a graphs of length of femur and length internode against time on the same axis.(7mks)
(b) (i)What was the average length of internode in the 8th week? (1mk)
(ii)Suggest how average length of internodes was obtained. (2mks)
(c) Name the type of growth curve shown by
(i) Grasshopper (1mk)
(ii) Seedling (1mk)
(d) Account for the change in length for fermur between
(i) 3rd and 7th week (2mks)
(ii) 16th and 20th week (2mks)
(e) (i) State what causes increase in length of internodes in the seedling. (1mk)
(ii) Exhibits the growth pattern of the femur. (1mk)
(iii) Name the hormone responsible for the growth pattern in grasshopper. (1mk)
(iv) Work out the rate of growth of the seedling between week 7 to 10 (2mks)

ANSWER EITHER QIESTION 7 OR 8 ONLY

7. (a). During a finance bill protest, tension was high and one of the police officer was furious and wanted
to face and fight a very aggressive protester. Explain the physiological changes that occur in his body to
prepare him for the fight. (14mks)
(b). (i) Identify each of the following responses described below.
(a). A person coughs whenever a foreign body irritates the respiratory tract (1mk)
(b). whenever a bell is rung, a dog is presented with a meal. After several days of practice, the dog
salivates once the bell is rung even if food is not available (1mk)
(ii) State the difference between the two responses identified in (b) above (4mks)
8.(i) State two significances of transpiration. (2 marks)
(ii) Discuss the forces involved in movements of water from roots to the leaves. (8 marks)
(iii) Describe the mechanism of opening and closing of stomata using photosynthesis theory. (10 marks)

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PREDICTION 6
PAPER 2
1. The diagram below shows the internal structure of a bean seed.

a) Name parts labelled A-D. (4mks)

b) What is the role of structure labeled X. (1mk)
c) What is the main difference between epigeal and hypogeal germination. (1mk)
d) Why is important that the radicle develops first during germination. (2mks)
2. The photograph below shows components of blood from a ruptured blood vessel. Study it and answer the
questions that follow.

a) Suggest the identity of the above blood vessel if a lot of digested food substances were found dissolved
in part T. (1mk)
b) Identify cell U and suggest its function. (2mks)
c) i) name three types of antigens that are likely to be present on the surface of the membrane of cell V
(3mks)
ii) Where in the human body is cell V produced? (1mk
d) What role does structure W play in blood clotting? (1mk)
3. (a) During a lesson, students observed the structure of a bat, cat and human forelimbs to determine their
evolutionary relationship.
(i) State the term used to describe the structure of the limbs observed by the students. (1mk)
(ii) Name the type of evolution illustrated by the structure of the limbs observed. (1mk)
(iii) What evidence of evolution is illustrated by the limbs. (1mk)
(iv) State the significance of the type of evolution illustrated by the limbs. (1mk)
(b) Explain how comparative embryology is an evidence for organic evolution in vertebrates. (2mks)

(c)Explain the theory of evolution by natural selection. (2mks)

4. In an experiment to investigate an aspect of digestion, two test tubes P and Q were set up as shown in the
diagram below.

The test tubes were left in the water bath for 30 minutes. The contents of each test tube was then tested for starch
using iodine solution.

(a) What was the aim of the set-up P? (1mk)

(b) What results were expected in test tubes P and Q. (2mks)
(c) Account for the results obtained in (b) above for test tubes P and Q.(2mks)
(d) Explain why the set up was maintained at 37oc. (1mk)
(e) Name the carbohydrate stored in. (2mks)
(i) Mammalian liver.
(ii) Potato tuber
5. Haemophilia is a genetic disease which is transmitted through a recessive gene linked to the X chromosome.
The normal gene may be represented by H and the gene for haemophilia may be represented by h.
(a) A woman who is a carrier for haemophilia married a normal man. Work out the expected genotypic and
phenotypic ratio of their children. Show your working. (6mks)
 (b) Haemophilia is more common in men than in women. Explain. (2mks)
6. The table below shows how quantities of sweat and urine vary with external temperatures

External temperature (0c) Urine cm3/h Sweat cm3/h

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) Using the same axes, draw a graph of quantity of urine and sweat against the external
temperature. (7 marks)
(b) (i) State the quantity of urine and sweat produced when external temperature was 12.50c. (2mks)
(ii) State the physical process through which the body was cooled by sweating as temperature was rising.
(1mk)

(iii) Account for the quantity of urine produced as the temperature increased. (4mks)

(c) State three nitrogenous wastes that could be eliminated in urine or sweat in human beings. (3mks)

(d) State three behavioral mechanism that poikilotherms use to regulate their body temperature under hot
conditions. (3mks)

7.Describe causes and methods of controlling water pollution. (20mks)

8.a) Name the tissues involved in support in plants. (4mks)

b). Explain how the ear brings about balance in relation to movement of the head. (16 mks)
PREDICTION 7
PAPER 2
SECTION A (40 MARKS)
1. The following is a diagram representing stoma in terrestrial plants. Q is the appearance when P was placed
in the dark for 6 hours.

a) State the importance of closure of A being as seen in Q to the plant (1mk)

b) State TWO modifications found in Cells B and not C (2mks)

c) What is the importance of part A to photosynthesis? (1mk)

d) Account for appearance of A as seen in Q using the Potassium Ion theory (4mks)

2. The following is an illustration of an important feature of the nervous system

a) Name the chemical found in part labeled B (1mk)

b) Give the importance of the structure above to the functioning of the nervous system(1mk)

c) What is the significance of high number of organelle A in the region X? (2mks)

d) Describe how an impulse reaches region marked Y (4mks)

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3. .In a given species of beetles, a cross between red wing beetle and orange wing beetle produces F1 off-
springs with yellow wings.
a) Explain the absence of red wing and orange wing in the F1 (2mks)

b) If the F1 were selfed, work out the genotypes of the offspring’s

(use capital R to represent the gene for red colour and capital O for the orange colour)(4mks)

c) From the genetic cross in b) above give the following:

i) Genotypic ratio (1mk)

ii) Phenotypic ratio (1mk)

4. Use the illustration of a cell shown below to answer questions that follow

a) Give TWO reasons why the above is an animal cell. (2mks)

b) i) State the identity of organelle T (1mk)

ii) Identify the substance processed in organelle R (1mk)

c) Which letter represents organelle that will be abundant in the following? (2mks)

i) Muscle tissue

ii) Secretory glands.

d) State the significance of the following properties to the functioning of P (2mks)

i) Being Polarised.

ii) Semi-permeability

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5. The following diagram is an illustration of kidney nephron

a) Identify the parts labeled: (2mks)

i) 6

ii) 7

b) State the importance of the following observations:

i) Vessel 2 being wider than vessel 5 (1mk)

ii) Concentration of urea is higher in region 8 than in region 4 (1mk)

c) Explain the importance of adrenal glands in region 4 when the blood has low ionic concentration
(2mks)

d) State the adaptations of region 7 in relation to mitochondria and microvilli (2mks)

SECTION B (40 MARKS)

Answer Question 6 which is Compulsory; then choose either Question 7 or 8

6. The table shown below was developed after an experiment where raw potato strips were placed in different
concentrations of sucrose.
Concentration Initial length Final length Change in Percentage
of sucrose of potato of Potato strip length of potato Change in length
solution strip (mm) (mm) strip (mm) of Potato strip
(mol/dm3) (%)
0.0 50.0 53.0 3.0
0.2 50.0 52.0 2.0
0.4 50.0 51.0 1.0
0.6 50.0 50.5 0.5
0.8 50.0 49.0 -1.0
1.0 50.0 48.0 -2.0

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 1.2 50.0 48.0 -2.0

a) Complete the table above by filling in the column for percentage change in length of potato strip (%)
(3mks)

b) Account for the change in length of the potato strip at the following concentration of sucrose:
i) 0.2mol/dm3 (2mks)
ii) 0.8mol/dm3 (2mks)
iii) 1.0 - 1.2 mol/dm3 (2mks)
c) On the graph below draw a graph of percentage change in length of the potato strip against

concentration of sucrose. (6mks)

d) Determine the normal concentration of the potato cell sap from the graph. (1mk)

e) i) Explain how a potato strip placed at 1.4mol/dm3 can regain its normal shape.(1mk)

ii) Name the process described in e (i) above (1mk)

f) State TWO importance of Osmosis to animals. (2mks)

7. a) During an ecological field study involving collection and observation of specimen, give SIX
precautions that need to be observed. (6mks)
b) Describe the effect of increased physical activity of an athlete on the following organs.
i) Skin (7mks)
ii) Heart (7mks)
8. a) Describe the process of exhalation in members of Class Mammalia. (8mks)
b) Explain why drug abuse should be discouraged among youths. (12mks)

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