133/2 BIOLOGY 2

For Both School and Private Candidates)

Time: 3 Hours Tuesday, 10" May 2016 p.m.

Instructions

1. This paper consists of eight (8) questions in sections A. B. C and D.
2. Answer five questions by choosing at least one (I) question from each section.
3. Each question carries twenty (20) marks.
4. Except for diagrams that must be drawn in pencil, all writing should be in blue or black ink.
5. Cellular phones are not allowed in the examination room.
6. Write your Examination Number on every page of your answer booklet(s).

SECTION A

1.(a) Give five reasons to justify the class to which cockroach belongs.

(b) Using examples, explain seven advantages of insects to human beings.

2.Using diagrams and one example in each case, classify bacteria on the basis of their morphology.

SECTION B

3.(a) Explain four major roles of the kidney.

(b) Describe the structure of the mammalian nephron.

4.Explain different ways used by endotherms to keep their body temperature constant.

SECTION C

5. (a) Explain the following types of growth; give one example in each case

(i) Intermittent growth

(ii)Allometric growth

(iii)Isometric growth

(iv)Limited growth

(v)Unlimited growth

State the roles of the following factors in seed germination:

(i)Water

(ii)Air

(iii)Optimum temperature

6. In guinea pig (Cavia), there are two alleles for hair colour, black and white, and two alleles for hair length, short and long. In a breeding experiment all Fl phenotypes produced from a cross between pure-breeding short-black haired and pure-breading. long white-haired parents and short black hair.

(a) Which alleles are dominant? Give reason for your answer. (b) Use cross diagrams to show both Fl and F2 results.

SECTION D

7. Explain how different abiotic factors affect population distribution

8. Describe the types of communities (Biomes) and their global distribution