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KCSE BIOLOGY TOPICAL EXAMS

GENETICS

1. a) What is a test cross? (1 mark)

b) The figure below is a structural diagram of a portion from a nucleic acid strand.

P SP S P S P
| | | |
C G U C
Giving a reason, name the nucleic acid to which the portion belongs. (2 marks)
c) Write down the sequence of bases of the complimentary strand to that shown above. (1 mark)
2. The diagram below shows a template strand of Deoxyribonuclenic acid molecule.

AA G T A T C G
a. i) Complete the diagram by drawing the missing complimentary strand. (1 mark)
ii) Name two chemical components that make the backbone of deoxyribonuclenic acic molecule.
(2marks)
b. A woman who is a carrier for haemophilia got married to normal man. Work out the genotypes of
the offsprings. Take the gene for haemophilia to be “h” (4 marks)
c. Name one disorder in humans due to chromosomal mutations. (1marks)
3. Explain why the garden pea plant was preferred by Gregor Mendel in his crossing experiments (3mks)

4. Give two structural differences between DNA and RNA molecules. (2mks)

5. In a certain plant species which is normally green, a recessive gene for colour (n) causes the plant to be
white when present in homozygous state such plants die at an early stage; The plants are pale green in
colour when in heterozygous state and grow to maturity.
(a) Give a reason for the early death of plants with homozygous recessive gene. (1mk)
(b) If a normal green plant was crossed with the pale green plant, what would be the genotypes of the F 1
generation (use punnet square to work out the answer)
(c) If seeds from the heterozygous plants were planted and the resulting seeds planted, work out the
phenotypic ratio of plants that would grow to maturity. (3mks)
(d) Explain the occurrence of the pale green colour in the heterozygous plants. (1mk)
6. Mr. Juma has sued Serenity Hospital on grounds that their child was wrongly identified such that they got the
wrong one. The child is blood group O. Mr. Juma is blood group AB while Mrs. Juma is heterozygous blood
group A.
a. Work out the possible blood group of their offsprings. (4 marks)

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 b. Is Mr. Juma justified in his claims? (1 mark)
7. The diagrams below illustrate some chromosome mutations.

A B A U
U
B V V
C W W

D X X
C J J
E E
K K L
L L F K F

M M

a. Identify the mutations illustrated above. (3 marks)

b. Give an example of a disorder in humans caused by mutation A above. (1 mark)
c. Name a disorder of blood caused by gene mutation. (1 mark)
d. Name two mutagens. (2 marks)
e. Give an example of a beneficial mutation in plants. (1 mark)
8. a) Name two disorders in human caused by gene mutation (2marks)
b) Give two examples of continuous variation in plants (2marks)
9. In maize the gene for the purple colour is dorminant for the gene for white colour. A purple colour was
crossed with heterozygous plant. Using letter G to represent the gene for purple colour, work out the
genotypic ratio of the offspring. Show your working. (5marks)

10. The following are short messages (sms) on cell phone communication between Mrs. Mkenzie and her
husband. They can be used as analogies of gene mutation
Intended message Actual message
1. I want a drive I want a driver
2. Yesterday was my shopping day Yesterday was my hopping day
3. My skirt was stolen My shirt was stolen
4. Tomorrow I will be visiting my team Tomorrow I will be visiting my mate

a For each of these messages identify the type of gene mutation illustrated (4marks)
b State one example of chromosomal mutation that lead to
i Change in chromosomal structure (1mark)
ii Change in chromosomal number (1mark)
c Explain why genetic counseling is termed as one practical application of genetics (2marks)

11. (a) Name two disorders in man that occur through gene substitution. (2mks)
(b) Give one advantage of polyploidy. (1mk)

12. A man with normal skin colour got married to a woman with normal skin colour. They gave
birth to three children; one of them an albino.

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(i) Identify the probable genotype of the parents using letter (A) for normal gene and (a) for (2mks)
defective gene.
Man:
Woman:
(ii) Using a genetic cross; show the genotypes of the offspring. (3mks)
(iii) Give the phenotypic ratio of the offsprings. (1mk)
(iv) Give two examples of sex linked genes. (2mks)

13. a) what is sex linkage? (1mark)

b) Name the sex linked trait that are only in male (2marks)
14. Pure breed of red cows and pure breed of white bulls were crossed to give F1 calves which had a mixture
of red and white coat known as roan. The F1 were selfed.
(a) Using letter R to represent gene for red colour and W to represent gene for white colour work out the
phenotypic ratio of
F2. (4 marks)
(b) Work out the genotypic ratio of a cross between F1 offspring and white bull. (3marks)
(c) Comment on the gene(s) controlling the colour of coats in cattle mentioned above. (1mark)

15. (a) What is mutation? (1mark)

(b) Name one disorder caused by gene mutation and one disorder caused by chromosome mutation.
(2marks)
Gene mutation
Chromosome mutation
16. a) What is heterozygous advantage? (1 Mark) b) Give an example. (1 Mark)

17. (a) What is meant by the term (2mks)

(i) Allele
(ii) Test cross
(b) Describe the following chromosomal mutations:
i) Inversion (1mks) ii) Translocation (1mks)
(c) In mice the allele for black fur is dominant to the allele for brown fur. What percentage of offspring
would have brown fur from a cross between heterozygous black mice? Show your working. Use letter B
to represent the allele for black fur. (4mks)

18. Explain the meaning of the following terms

i) Phenotype (1 mark)
ii) Test cross (1 mark)
19. The diagram below represents a stage during cell division

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 ii) Give two reasons for your answer in a) i) above (2mks)
b) Name the structure labeled M (1 mark)
20. A cross between a red flowered plant and while flowered plant produces plants with pink flowers. Using
letter R to represent the gene for red colour and W for white colour,
a. What were the parental genotypes? (1 mark)
b. Work out a cross between F1 plants. (4 marks)
c. i) Give the phenotype ratio of F2 plants (1 mark) ii) Genotypic ratio of F2 plants (1 mark)
d. Name the characteristic in humans which is controlled by multiple alleles (1 mark)

EVOLUTION
1. The wings of a bird and those of a housefly adapt the two organisms to a boreal habitat.
i) Give the evolutionary process that may have given rise to these structures. (1 mark)
ii) What name is given to such structures? (1 mark)
2. The wings of a bird and that of insects are analogous structures.
(a) What are analogous structures? (2mks)
(b) Name this type of evolution. (1mk)
3. Name a vestigial structure found in:
(a)Man. (1mk)
(b)Whale. (1mk)
4. In a prolonged drought period, forage was scarce. It made animals reach out for higher forage and this way
the giraffes got the stretched long necks.
(a) What is the term used for a characteristic such as the long necks outlined? (1 mark)
(b) What is the name given to the theory that describes the evolution of such structures like the long necks?
a) i) Identify the stage of cell division (1 mark)
(1 mark)
(c) State and explain the limitation of the theory you named in (b) above. (2 marks)

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

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 a) Name the evolutionary process that may have given rise to these structures. (1mk)

b) What is the name given to such structures? (1mk)

c) Give two examples of vestigial organs in man. (2mk)

6. a) Outline the main features of Lamarckian theory of evolution.

(2mk)
b) In view of modern genetics, explain why Lamarck’s theory is unacceptable.
(1mk)
c) Name one factor in nature that increases the process of evolution.
(1mk)

7. (a) Define the term evolution (1 mark)

(b) State four sources of evidences that support the theory of organic evolution. (4 marks)
8. After a colony of penicillin-sensitive bacteria was exposed to antibiotic pencillin, a penicillin resistant
emerged. Explain this observation (2 Marks)

9. What is meant by speciation? (2 Marks)

10. a) what is natural selection? (4marks)

b) Describe four evidences for organic evolution. (16marks)

11. (a) Distinguish between homologous and analogous structures in evolution. (2mks)
(b) Give one limitation of fossil records as evidence for organic revolution. (1mk)

12. a) What are vestigial structures? (1 mark)

b) State one major importance of convergent evolution to living organisms. (1 mark)
c) Why is Larmarck‟s theory not popular with scientists? (1 mark)

13. (a) What is meant by the following term Adaptive radiation (1mk)

(b) Evolution is an ongoing process and is still going on even today. State two pieces of evidence which
suggests that evolution
is still taking place. (2mks)
(c) Explain how the following factors influence natural selection. (4mks)
(i) Predators
(ii) Diseases

14. (a) Define:

(i) Chemical evolution. 2mks
(ii) Organic evolution. 2mks

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15. 50 black mice and 50 white mice were released into an area inhibited by a pair of owls. After four months
38 of the black mice and 9 of the white mice were recaptured.
a. How this observation would be explained. (2 marks)
b. Name the theory of evolution that support the results in (a) above. (1mark)
c. Name two vestigial structures in man. (2 marks)

16. State two advantages of natural selection. (2 marks)

17. a) What are fossils? (1mark)

b) State two different types of fossils. (2marks)

c) State two limitations of the use of fossils as an evidence evolution. (2marks)

18. a) Give two reasons why the evolution of human enabled him to survive better than his hominid
ancestors. (2marks)
b) Why is Lamarck‟s theory of evolution not accepted by biologists today?
19. a) What is meant by the term vestigial structures? 1mk
b) Name the type of evolution illustrated by
i) Hind limbs of birds 2mks
ii) Wings of birds and insects. (1mark)
20. a) What is the difference between Darwinian and Larmackian theories of evolution. 2mks

RECEPTION, RESPONSE AND COORDINATION IN PLANTS AND ANIMALS

1. State the function of the following parts of the human ear.

a) Tympanic membrane (1 mark)
b) Round window (1mark)
2 State the fluids that provide cushion in the following organs (4 marks)
a) Lungs …………………………………………………………
a) Heart ……………………………………………………………
b) Knee ……………………………………………………………
c) Eye ball ……………………………………………………………
3 Study the diagram below showing a mammalian eye defect. (4mks)

Retina

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a) Identify the eye defect (1 mark)
b) How can the above defect be corrected (1 mark)
4. a) Describe the process of accommodation in the human eye. (10 marks)
b) Describe the mechanism of regulation of the amount of light entering the eye. (10 marks)
5.The diagram below shows a transverse section of a spinal cord.

Dorsal root White matter

Sense organ
(skin) pricked
A

Sharp pin

B Gray matter D

C Forearm

Name the parts labelled A – D.

6. The diagram below shows the point of focus of light from an object.

Name the eye defect shown above.

7. The diagram below shows how the iris and pupil of a human eye appear under different conditions.

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

(b) State the condition that leads to the change in appearance shown in the diagram labelled (1mk)
B.
(c) Describe changes that lead to the appearance of iris and pupil as shown in the diagram (4mks)
labelled B.
(d) What is the significance of the changes described in C above? (1mk)

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8.
The diagram below represents the structure of a nerve cell.

(a) Identify the nerve cell. (1 mark)

(b) Give a reason for your answer in (a) above. (1 mark)
(c) State the function of the part labelled T. (1 mark)
(d) Using an arrow show the direction of an impulse on the diagram. (1 mark)

9. State the functions of the following parts of a brain. (3marks)

a. Thalamus
b. Midbrain
c. Medulla oblongata
10. State three differences between Rods and Cones. (3marks)

11. The diagram below shows a mammalian eye.

a) Name the parts labeled R, S and T. (3 mks)

b) Give two adaptations of part labeled U. (2 mks)
c) Describe the changes that occur to part V when one moves from a bright room to a dark room. (3mks)

12. (a) What is eye accommodation? (1mk)

b) Explain how the Iris muscle controls the size of pupil when exposed to bright light. (2mks)

13. State two biological importance of tropisms in plants. (2mks)

14. An accident victim was found to pass large volumes of dilute urine.
a) What part of brain was injured?
(1mk)
b) Explain how the injury of the part of the part mentioned in 25(a) above brought about the release of
large volumes
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 of urine. (2mks)
15. (a) Describe the mechanism of hearing in man. (16mks)

(b) State four differences between endocrine and nervous systems. (4mks)

16. State the adaptations of the following parts of the eye to its function.
a) Choroid (2 marks)
b) Retina (2 marks)

17. State the functions of the following neurons.

a. Relay neurone (1 mark)

b. Motor neurone (1 mark)

18. a) The diagram below represents a section of the human brain.

i) Name the structures labeled P and R (2 marks)

ii) State two functions of the part labeled Q. (2 marks)
b) i) Name two reproductive hormones secreted by the pituitary gland in women (2 marks)
ii) State one function of each of the hormones named in (b) (i) above. (2 marks)
19. (a) In which part of the spinal cord is the cell body of the motor neurone found.
(b) Below are two features which make a neurone a specialised cell. State their roles.
(i) Axon.
(ii) Dendrites.

20. A person was able to read a book clearly at arm‟s length, but not at normal distance.
(a) State the eye defect the person suffered from. (1mk)
(b) Why was he unable to read the book clearly at normal distance. (1mk)
(c) How can the defect be corrected. (1mk)

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SUPPORT AND MOVEMENT IN PLANTS AND ANIMALS

1.The diagram below represents a mammalian bone.

a) State the function of the part labeled K and L (2mark)

b) State the region of the body in which the above bone is found. (1 mark)

2. (a) Name the hard body covering found in organisms of the phylum arthropoda. (1mk)
(b) Give two uses of the structure mentioned in (a) above. (2mks)

3. Below is a diagram showing the forearm bones and muscles covering

them?

(a) Name the bones represented by T, X, Y and (2mks)

Z. (b) Name the joint formed between:
(i) T and X. (1mk)
(ii) Y and X. (1mk)
(c) Name the muscles labelled P and R. (1mk)

(d) What happens to each muscle as the arm is (1mk)

straightened.
(e) Name two strengthening tissues in woody (2mks)
stems.

4. The diagram below represents a bone of a mammal.

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 (a) Identify the bone. (1 mark)
(b) Name the part marked X. (1 mark)
(c) Name the bone that articulates at the part labelled F. (1 mark)
(d) Explain one way in which the bone is adapted to its function. (1 mark)

5. The diagram below shows a joint in a mammal. Study it and answer the questions.

a. State the functions of parts A and B (2marks)

b. Name the type of joint illustrated by the diagram (1mark)
c. State two adaptations of joint named in (b) Above (2marks)

6. Name two structures in herbaceous stems that enhance their support. (2mk)

7. The diagram below represents a bone obtained from the hind limb of a goat.

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 (a) Identify the bone. (1mk)
(b) Name the type of joint formed at the part labelled T. (1mk)

8. Explain how the following tissues are adapted to provide mechanical support in plants.
(a) Collenchyma (1mk)
(b) Sclerenchyma (1mk)

9. State the role of intervertebral discs (1 mark)

10. State three structural differences between biceps muscles and muscles of the gut (3marks)

11. What are the functions of the odontoid process found on the axis bone of the cervical vertebra?(2mks)

12. Explain the adaptations of thoracic, cervical and lumbar vertebrae to their functions (12 marks)
13. a. Name two bones that form the pectoral girdle. 2mks
b. Name the cavity formed by the scapula that form a joint with the humerous. 1mk

14. The diagram below represent a mammalian bone.

c. Name the bone.

d. i) Which bone articulate with the bone shown in the diagram at the notch ? (1 mark)
ii) Name the type of joint formed when the bone in b(i) articulate. (1mark)

15. a) Name two supporting tissues in plants. (2 marks)

b. Study the diagram below and answer the question that follows.

i) Identify the muscle represented by X and Y. (2 marks)

ii) Describe how muscle X and Y cause straightening of joint Z. (2 marks)
c. Name joint Z. (1 mark)

16. The figures below illustrate specialized cells in an animal body.

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 a) Identify the cell M and N. (2marks)
b) State the structural differences between M and N (2marks)
c) Which of the above specialized cells is found in the gut. (1mark)

17. The diagram below shows the bones and two of the muscles in the human arm

a) Name the parts A, C, E and F. (4marks)

b) i) Name the type of joint present in part X and Y (2marks)
ii) What type of movement is possible at point X. (1marks)
c) What happens when the muscle labelled C contracts. (1mark)

18. State the importance of support in plants. (3marks)

19. The diagram below represents a human arm. Study it and answer the questions that follow.

a) Name bone T and R (2marks)

b) Name muscle C and D (2marks)
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c) i) Identify the fluid found at joint 2. (1mark)
i) State the function of the fluid in (i) above. (1mark)
d) i) What is the type of the joint found at part labeled 1. (1mark)
ii) Differentiate between a tendon and a ligament. (1mark)

20. a) Distinguish between a hinge joint and a ball and socket joint. 1mk
b) i) Name the cartilage found between the based of the vertebral column. 1mk
ii) State the function of the cartilage named in b (i) above 1mk

WE ALSO HAVE THE FOLLOWING TOPICALS FROM FORM 1 TO FORM 4

1. MATHS
2. ENGLISH
3. KISWAHILI
4. CHEMISTRY
5. BUSINESS
6. PHYSICS
7. GEOGRAPHY
8. HISTORY
9. CRE
10. AGRICULTURE

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