KCSE Past Papers 2014 Biology Paper 1 (231/1)

Biology 2014

4.4.1 Biology Paper 1 (231/ 1)

1. (a) Acquisition and utilization of nutrients; (1 mark)

(b) Elimination of metabolic wastes to prevent accumulation to toxic level; (1 mark)

2. (a) A period of rest in which a seed performs its physiological processes slowly and utilizes little food; (1 mark)

(b) – Chemical/growth inhibitors;

– Hard/impermeable seed coat;

– Low / freezing temperatures;

 

– Under developed embryo/immature embryo;

– Low concentration of hormones;

– Lack of appropriate light wavelength;

(max 3 marks)

3. – Exchange of nutrients /metabolic wastes/ gases between the mother and foetal circulatory systems;

– Secretion of progesterone hormone;

(2 marks)

4. (a) Tube nucleus;

(b) – One male nucleus fuses with the egg cell nucleus to form a zygote;

– The other male nucleus fuses with the polar nuclei to form the endosperm;

(2 marks)

5. (a) Hypertonic solution; (1 mark)

(b) Volume of sugar solution increases in the thistle funnel While that of distilled water in the beaker reduces; because the thistle funnel gains distilled water by osmosis.

(2 marks)

6. – Cell division;

– Cell elongation;

– Development of adventitious roots;

– Formation of callus tissue;

– Causes apical dominance;

– Causes tropic responses.

3 x 1 (3 marks)

7. Object length = 12 cm

Drawing length = 6 cm

M _ Drawing length _ _i_

g — Object length ’ — 12 ’

= X 0.5;

(2 marks)

8. – Phenotype is the outward appearance of an organism while Genotype is the genetic make up of an organism; (1 mark)

9. – Act as shock absorbers;

– Allow smooth movement between the vertebrae/reduce friction; (2 marks)

10. (a) – Absorption of materials e.g. diffusion of digested food into the blood stream;

– Gaseous exchange e.g. CO2/O2 diffuses from capillaries into the alveoli.

– Excretion of nitrogenous Wastes; e.g urea diffuses from blood capillaries into the elimination sites. (max 4 marks)

(b) (i) Crenated cell is a shrunk animal cell that has lost water by osmosis; (1 mark)

(ii) Flaccid cell is a flabby /shrunk plant cell that has lost waster by osmosis; (1 mark)

11. Tactic Responses Tropic Response

– Are locomotory – Are growth responses;

– Are fast – Are slow;

– Not influenced by growth hormones – Are caused by growth hormones;

– Temporary – Permanent;

(3 marks)

12. (a) (i) Rib-cage/chest cavity; ( 1 mark)

(ii) Diaphragm; (1 mark)

(b) The balloons are inflated; (1 mark)

(c) Pulling down the string increases the volume of D, hence decreasing the pressure inside;

The low pressure causes external atmospheric air to rush in and inflate the balloons; (2 marks)

13. (a) Trap foreign particles entering the eye;

Produce fluid/tears; (1 mark)

(b) – Moistens the comea;

– Wash foreign materials out of the eye;

– Antiseptic / kills harmful microorganisms; ‘ ‘ ‘ ‘

14. DNA RNA

Double stranded/double relix Single stranded;

Has Thymine Thymine is replaced by uracil/reject Thiamin;

Has the four nitrogen base pairing pattern Lack the four nitrogen base pairing pattern;

Deoxyribose sugar Ribose sugar;

(3 marks)

15. (a) Skeletal muscles / striated muscles; (1 mark)

(b) Tendon is a (inelastic) tissue that attaches muscles to bones while Ligament is a (inelastic) tissue that attaches a bone to another bone of a movable joint;

(1 mark)

16. (a) Sensory neurone; (1 mark)

(b) Cell body is located off the axon/tied outside the CNS; (1 mark)

(c) Schwann cell; (1 mark)

(d) (i) Receipt/transmits impulses to neighbouring neurons in the CNS from sense organs; (1 mark)

(ii) Insulates the axon/accept dendron for axon; (1 mark)

17. The blind spot lacks both cones and rods hence images are not perceived; (1 mark)

Accept photoreceptor cells for cones and rods;

18. (a) To provide a cool environment; that is conducive for sperm formation; (2 marks)

(b) Progesterone hormone; is secreted by the placenta to maintain the pregnancy; (2 marks)

19. Due to limited oxygen, haemoglobin combines With carbon (II) oxide to form carboxyhaemoglobin;

Carboxyhaemoglobin does not readily dissociate hence reduces the capacity of haemoglobin to transport oxygen; Carbon (II) oxide is therefore a respiratory poison if breathed in for a long time;

(3 marks)

20. (a) Packaging of substances/glycoproteins/ transportation of glycoproteins; Secretion of synthesized proteins and carbohydrates;

Formation of lysosomes/modification of carbohydrates to form glycoproteins; (1 mark)

(b) – Digestion of food/Breakdown large molecules;

– Destroy Worn out organelles or cells/tissue;

(max 1 mark)

21. (a) Exoskeleton;

(b) Endoskeleton; ( 1 mark)

22. (a) Appendix/accept nictating membrane; coecum and ear drum;

Tail/coccyx; ( 1 mark)

(b) They have a gene for resistance/acquire it through mutation;

The gene for resistance is passed to offsprings establishing a population of resistant forms;

(2 marks)

23. (a) K – Photosynthetic products/manufactured foods example vitamins/alicose/proteins/ sucrose/maltose/fructose/lipids/nitrates; ( 1 mark)

L – Water and mineral salts; (1 mark)

(b) The substances are moved into the star shaped xylem; (1 mark)

24. M – lungs; (1 mark)

N – Urea,ammonia,; (1 mark)

P – Digested food,Water; mineral ions; (1 mark)

25. – Stimulates maturation of the Graafian follicle/stimulates ovulation;

– Stimulates corpus luteum to secrete progesterone hormone;

– Stimulates release of androgens;

– Stimulates development of corpus luteum;

(2 marks)

26. (a) (i) Diffusion; ( 1 mark)

(ii) Sea water contains a higher concentration of sodium ions than the cell sap; (1 mark)

(b) (i) Iodide ions; (1 mark)

(ii) Sea water has a lower concentration of iodide ions than the cell.

The plant requires energy to take up the iodide ions (by active transport); (1 mark)

27. (a) Spiracle; ( mark)

(b) Keep the trachea open for air passage; ( mark)

(c) – Lacks spiral bands of chitin / to make it thin; for diffusion of gases

– Moist; to dissolve respiratory gases;

(2 marks)

 

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