2

FORM 2

BIOLOGY THEORY

EXAMINATION

TIME: 2 HOURS

INSTRUCTION

This paper consists of two section A and B.

Answer all questions in the spaces provided.

SECTION A

1.  State two functions of muscles found in the alimentary canal of mammals. (2 marks)

2.  Adult elephant flap their ears twice as much as their calves in order to cool their bodies when it is hot. Explain. (2 marks)

3.  (a) State the function of co-factors in cell metabolism. (1 mark)

(b) Give two examples of a metallic co-factor. (2 marks)

(c) Distinguish between competitive and non-competitive enzyme inhibitors (2 marks)

4.  What happens to excess fatty acids and glycerol in the body. (2 marks)

5.  Name two cells in the human body that have the power of locomotion and give one function of each cell. (4 marks)

Cell / Function

6.  (a) State the role of the pulp cavity in a mammalian tooth. (2 marks)

(b) What is the use of the diastema in a herbivore? (1 mark)

(c) Name a disease caused by lack of each of the following in human diet.

Vitamin D (1 mark)

Iodine (1 mark)

7.  The temperature of a person was taken before, during and after taking a cold bath. The results are shown in the graph below.

37

36

35

Time (minutes)

(a) Explain why the temperature fell during bath. (3 marks)

(b)  What changes occurred in the skin that enabled the body temperature to return to normal.

(4 marks)

8.  (a) State one biological explanation for each of the following facts.

i.  Plants with large leaves lose more water than with small leaves. (1 mark)

ii. A person who has fewer red blood cells than usual feels weak (anaemic).(1 mark)

iii.  The immediate treatment for a person with diarrhoea is to give him a glass of slightly salted water. (1 mark)

iv.  We should brush our teeth before going in to bed. (1 mark)

(b)  Give two reasons why our diet should always contain fruits and vegetables. (2 marks)

9.  The table below shows daily requirements of energy and some food nutrients for different sexes and occupations.

Occupation and sex / Energy (KJ) / Proteins (g) / Calcium (mg) / Iron (mg)
Male bank manager / 9200 / 70 / 0.5 / 12
Wheel cart driver (25 years) / 12800 / 90 / 1.5 / 17
School boy (15 – 18 years) / 12700 / 115 / 0.8 / 17
Female bank manager / 7500 / 60 / 0.6 / 20
Pregnant typist / 9500 / 110 / 1.2 / 20
School girl (15-18 years) / 10500 / 90 / 0.7 / 19

(a) Giving reasons for the differences, compare the daily requirements of the wheel cart driver and the school boy. (6 marks)

(b) The amount of calcium required by the pregnant typist is higher than that required by the female bank manager. Give a reason for this. (2 marks)

(c) Give a reason for the difference in iron requirements between the school boy and the school girl. (1 mark)

(d) Explain why the male bank manager requires more energy than the female bank manager. (1 mark)

(e)  Name two major sources of calcium and two major sources of iron in the diet of man.

Sources of calcium (1 mark)

Sources of iron (1 mark)

10. Two shoots , A – a monocotyledonous plant and B – a dicotyledonous plant, are placed in a beaker of red ink for three hours. At the end of the period, transverse sections of the stems are cut.

(a)  What will you observe if transpiration has been going on with the plants? Explain your observations. (1 mark)

Shoot A

Reason (1 mark)

Shoot B (1 mark)

Reason (1 mark)

(b)  If a thick strip of the bark 1.25cm in length all – round is removed over the whole girth of shoot B state what would happen and explain why. (2 marks)

SECTION B: (20 MARKS)

11. Explain how environmental factors affect transpiration process in flowering plants.(20 marks)