2010 KCSE Biology Paper 1 -Free KCSE Past Papers with Answers.

2010 KCSE Biology Past Paper

1. State the name give to the study of:
a) The cell (1 mark)
b) Micro–organism. (1 mark)

2. The diagram below shows a transverse section of a plant organ.

a) Name the plant organ from which the section was obtained. (1 mark)
b) i) name the class to which the plant organ was obtained (1 mark)
ii) Give a reason for your answer in (b) (i) above (1 mark)
c) Name the part labeled X. (1 mark)

3. State the function of:
a) Ribosomes (1 mark)
b) Lysosomes (1 marks)

4. The diagram below shows a specialized plant cell.

a) i) Name the cell (1 mark)
ii) Name the parts labeled D and E. (2 marks)
b) state the function of the part labeled C. (1 mark)

5. state three ways in which a respiratory surface is adapted to its function. (3 marks)

6. State one function for each of the following:
a) Cerebellum (1 mark)
b) Medulla oblongata (1 mark)

7. Distinguish between haemolysis and plasmolysis. (2 marks)

8. State three external differences between chilopoda and diplopoda. (3 marks)

9. State two ways in which chloroplasts are adapted to their functuions. (2 marks)

10. State two advantages of hybrid vigour. (2 marks)

11. The diagram below shows a transverse section of leaf.

a) Name the habitat of the plant from which the leaf was obtained. (1 mark)
b) Give one reason for your answer in (a) above. (2 marks)

12. The diagram below illustrates the structure of bread mould.

a) Name the part labeled J (1 mark)
b) State the function of the structure labeled K (2 marks)

13. What is meant by the following term?
a) Habitat; (1 mark)
b) Ecosystem (1 mark)

14. Explain why is not advisable to be in a poorly ventilated room with a burning charcoal. (3 marks)

15. A potted plant was kept in the dark for 48 hours. Two leaves X and Y were treated as shown in the diagram below.

The experimental set-up was kept in sunlight for 6 hours after which a starch test was carried out on the two leaves.
a) What were the results of the starch test on leaves X and Y? (2 marks)
b) Give reasons for your answers in (a) above. (2 marks)

16. What is the role of bile salts in humans? (2 marks)

17. The following is the dental formula of a certain mammal:
i 0/3 c 0/1 pm 3/3 m3/3
a) State the likely mode of feeding for the mammal. (1 mark)
b) Give a reason for your answer in (a) above. (1 mark)

18. Give two reasons why animals have specialized organ for excretion as compared to plants (2 marks)

19. State the changes that occur in arterioles in the human skin during thermoregulation. (2 marks)

20. State two advantages of internal fertilization in humans. (2 marks)

21. The diagram below represents part of the human skeleton.

a) Name the part labeled P (1 mark)
b) i) Name the bone the articulates with the part labeled Q. (1 mark)
ii) What type of joint is formed between the part labeled Q and the bone named in (b) (i) above?(1mk)

22. What is the function of the following structure in the human reproductive organ?
a) Fallopian tubes. (1 mark)
b) Epididymis. (1 mark)
c) Scrotl sac (1 mark)

23. Explain three ways in which red blood cells are adapted to their function. (3 marks)

24. . a) State two ideas proposed by Lamark in his theory of evolution. (2 marks)
b) Why is Larmark’s theory not acceptable? (1 mark)

25. State three factors that contribute to the deceleration phase in the population curve of an organism (1 mark)

26. State one survival value for each of the following in plants:

a) Thigmotropism in stems; (1 mark)
b) Geotropism in roots. (1 mark)

27. . a) What is meant by the term non-disjunction? (1 mark)
b) Give an example of a genetic disorder caused by:
i) Non-disjuction; (1 mark)
ii) Gene mutation ( 1 mark)

28. State three structural differences between arteries and veins. (3 marks)

29. The diagram below represents a female cone.

a) Name the subdivision of the plant from which the cone was obtained. (1 mark)
b) Other than the presence of cone, name two other external features that identify plants in the subdivision named in (a) above. (2 marks)

30. What is meant by the apical dominance? (3 marks)

2010 KCSE Biology Paper 1 Past Paper-Marking Scheme/Answers

1. (a) Cytology: Rej cell biology
(b) Microbiology

2. (a) Stem
(b) i) Monocotyledonae
ii) Vascular bundles scattered not arranged in a ring; Absence of pith; Absence of vascular cambium.
(c) Epidermis

3. (a) Protein synthesis (Accept: site for protein symbiosis)
(b) Destroys worn out organelles/cells/tissues
Destroys micro-organisms.

4. (a) i) Root hair(cell)
ii) D – cell wall
E – cell sap (vacuole)
(b) Controls the functioning of the cell/ controls cell activities

5. A large surface area for efficient diffusion of gases
Moist for gases to diffuse in solution form/to dissolve gases
Thin for efficient/diffusion of gases (across a short distance)
Most be close to body cells/well supplied with blood vessel to active cells
Ventilation mechanism for bringing in air rich in O2 and expelling air rich in carbon(iv) oxide

6. (a) Maintain balance/posture/control/muscular movement
(b) Control heart beat/ blood pressure/ breathing(rate) control involuntary activities/ response
Accp. Curved examples of v.a e.g. eating, swallowing e.t.c.

7. Haemolysis – process by which red blood cells take in water till they burst;
while Plasmolysis – loss of water from plant cells until the cell membrane is detached from the cell wall/ until the cell become flaccid.


9. – They contain chlorophyll which traps/absorb light (energy)
– They have grana which increase surface area for accommodation of a large number of chlorophyll molecules for photosynthesis
– The stoma has enzymes for photosynthesis

10. – Resistance to diseases/pests/adverse weather conditions (Acc. Correct examples e.g. drought, very high/ low temperatures
– Increased yields
– Earlier maturity Acc. Early maturity

111. (a) Aquatic / fresh water
(b) Large air space/aerenchyma Sclereids
Stomata on upper epidermis/absence of stomata in lower epidermis
Absence of cuticles
Poorly developed vascular bundles

12.(a) J – sporangium
(b)- Absorption of soluble substances/ digested food
– Secretion of digestive enzymes;
– Anchorage(of mould on substrate); anchorage must be in the right context

13. (a) Place/environment in which (specified)organism lives
(b) A natural unit with abiotic and biotic factors

14. Charcoal in limited supply of air produces carbon(ii)oxide; which combines with haemoglobin forming carboxyhaemoglobin; which is stable/ does not dissolve reducing capacity of the haemoglobin leading to suffocation/ death;

15. a) X – Starch present
Y – Starch absent
b) X – acts as a control; Y – CO2 absent absorbed by potassium hydroxide pellets; Acc correct explanation

16. Emulsification / breaking down of fats into (tiny) droplets
Creating alkaline medium for digestive enzymes/ neutralizing acidic chyone (from the stomach)

17. (a) Herbivorous; Rej Harbivores
(b) Lack canines/ incisors on upper jaws

18. Animal form waste products more rapidly than plants/ Produce more metabolic wastes
Animals don’t reuse their waste while plans reuse some of their wastes;

19. When temperature is high they dilate; when low they constrict (Acc. Vasodilatation)

20. Higher chances of fertilization
Embryo/gamete is protected from external environment conditions

21. (a) P – sutures
(b) i) Atlas;
ii) Hinge joint

22. (a) Passage of ova/ site of fertilization
(b) Storage of sperms
(c) Hold the testis/ protect the testis

23. – Absence of nucleus, increase of space for packaging haemoglobin(for carrying oxygen)
– Possession of haemoglobin which has high affinity for oxygen
– Bi-concave shape creates large surface area for combining with oxygen
– Ability to change shape/flexible to enable them pass through capillaries.
– Have carbonic anhydrate which increase CO2 transportation
– Are numerous/many to be able to carry max amount of oxygen
– Has plasma membrane which allow rapid diffusion of gases

24. (a) Use and disuse
Acquired traits can be passed on to offspring
(b) Acquired characteristics cannot be inherited
No evidence to support the theory

25. – Overcrowding
– Accumulation of toxic wastes
– Limited resources such as nutrients

26. (a) Provide support
Enables plants to grow forward light
(b) In search of nutrients

27. (a) Failure of homologous chromosomes to segregate during meiosis/ anaphase I/ meiosis I
Failure of sister chromatid to segregate during meiosis/ anaphase II / meiosis II.
(b) i) Down’s syndrome; Turner’s syndrome; Klinefelter’s syndrome
Surnerz syndrome
Acc. Mongolism for Doran’s syndrome
ii) Albinism; single cell anaemia; heamophilia; colour blindness
Chondrodytrophic dwarfism/ Achondroplasia

28. Arteries have thick muscular walls; veins have thin and less muscular walls
Arteries have narrow lumen, veins have wider lumen
Arteries have no valves except at junction with heart; veins have valves at regular intervals.

29. (a) Gymnospermae/ Gymuspermatophyta/ Gymnosperonaphyta;
(b) Needle-like leaves; thick waxy cuticle
Naked seeds; sunken stomata.

30. The inhibition of growth of lateral buds; by auxins; produced by the growing apical bud.