THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA CERTIFICATE OF SECONDARY EDUCATION EXAMINATION

BIOLOGY

(For Both School and Private Candidates)

Time: 3 Hours Year: 2003

SECTION A

1. For each of the items (i) — (x) choose the correct answer from the given alternatives and write its letter beside the item number.

(i)The release of an egg cell from the ovary is known as:

1. Evolution
2. Menstruation
3. Ovulation
4. Ecdysis
5. Parturition

(ii) Maintenance of a constant internal environment means:

1. Osmoregulation
2. Excretion
3. Re-absorption
4. Homeostasis
5. Secretion

(iii) If a parent cell has 12 chromosomes, how many chromosomes will be in the daughter cells formed after meiosis?

1. Six (6) 
2. Twelve (12) 
3. Eighteen (18)
4. Twenty(20)
5. Thirty six (36)

(iv)Viruses are considered to be non-living because:

1. They are only active in the contents of a living cell
2. They have true nuclei 
3. The body is covered by a cell wall
4. They are single-cell eukaryotic organisms. 
5. They are multicellular organisms.

(v)Study Fig. 1 below carefully, and answer the question below. The aim of the experiment was to investigate the 

Figure 1

1. Use of aluminium foil on plant leaves
2. Necessity of chlorophyll for photosynthesis 
3. Necessity of light for photosynthesis
4. Presence of starch in the leaf
5. Importance of water in photosynthesis

(vi) Which of the following joints allow movements in one plane only?

1. Ball and socket 
2. Gliding
3. Hinge
4. Immovable 
5. Gliding and immovable

(vii) The stamen of a flower consists of:

1. Stigma and ovary
2. Anther and stamen 
3. Filament and ovary 
4. Anther and filament
5. Ovary and anther

(viii) An experiment:

1. always guarantees scientific conclusion
2. should always be carried out in the laboratory
3. suggests a hypothesis
4. is valid only when it is carried out with a control 
5. must start with a hypothesis and end up with the identification of a problem.

(ix) In which of the following tissues can rapid mitotic cell division be seen?

1. Nerve
2. Heart
3. Embryonic
4. Muscle
5. Epidermal

(x) Which of the following series of activities take place together when focusing distant objects?

1.  Ciliary muscles relax and the lens becomes thin
2. Ciliary muscles contract and the lens becomes thin 
3. Ciliary muscles contract and the lens becomes thick
4. Ciliary muscles relax and the lens becomes thick
5. Ciliary muscles relax and pull the lens into its normal round shape.

2. Match the items in list A with the responses in List B by writing the corresponding response beside the item number.

SECTION B

3.An ecologist carried out a survey to estimate the number of organisms in a certain dam. The results were as shown in Table 1 below.

(a) Which of the above organisms are called:

(i)producers?

(ii)primary consumers?

(iii)consumers of the last order?

(b)Which organisms are likely to be finished first in the dam? Give reason(s) to support your answer.

(c) Draw a food web to show energy flow among organisms in the dam.

4.(a) (i) What is gaseous exchange?

(ii) Arrange the following in the correct order: Bronchi, pharynx, bronchioles, nasal passages, alveoli, trachea,

(b)Name the structures concerned with gaseous exchange in:

(i) a mammal

(ii) a young tadpole

(iii) an insect

(iv) an earthworm

(v) a spider

(c) What is the differ nce between the functions of a ligament and a tendon?

5.(a) Study the Figure below and then answer the questions that follow.

Fig. 2

(i) Name the parts labelled A, B, C and D.

(ii)State the function(s) of D.

(iii)What is the main difference between guard cells and other epidermal cells?

(b) How is the process of respiration different from burning?

6.Below is a diagram of an imaginary cell. Observe the the questions that follow.

Fig. 3

(a) (i) How many chromosomes are there altogether?

(ii) How many pairs of homologous chromosomes are there?

(b) (i) If this cell divides by mitosis, how many chromosomes will be in each daughter cell?

(ii) If the cell divides by meiosis how many chromosomes will each daughter cell contain?

(iii)If the cell divides by meiosis how many daughter cells will be formed?

7. Fig 4 shows a human uterus during pregnancy.

Fig. 4

(a)(i) Name the parts labelled A, B, C, D and E.

(ii) Give one function of the parts labelled B and C.

(b) (i) Name two substances that pass from the mother's blood to the blood of the foetus.

(ii) In what way(s) does a zygote differ from any other cell in the body?

8.(a) (i) What are the characteristics of viruses? 

(ii) How do viruses differ from bacteria?

(b)Study the Figure below and then answer the questions that follow.

Fig. 5

(i)What does Fig. 5 represent?

(ii)Name the parts labelled A, B, C, D and E.

(c)Arrange the following in the correct order for a simple reflex arc: 

Impulse travels in motor fibre, impulse travels in sensory fibre, effector organ is stimulated, receptor organ is stimulated, and impulse crosses synapse.

9.(a) Differentiate between responsible behaviours and risky behaviours.

(b) State two behaviours which may lead to the following risks:

(i) STDs

(ii)HIV infections

(iii)Drug abuse

(iv)Unplanned pregnancies

(c) Suggest how victims of HIV/AIDS can be cared and supported.

10. (a) (i) Define osmosis.

(ii) Does the presence of a cell wall prevent the process of Give reason(s) to support your answer.

(iii) How does osmosis differ from diffusion?

(b) (i) Distinguish between phototropism and geotropism.

(ii) Name the hormone responsible for tropic responses in plants. (iii) Name three diseases transmitted by polluted water.

SECTION C

11. Write an essay on population growth using the following guidelines:(a) Meaning of population.

(b) Factors influencing rapid human population growth and distribution. (c) Factors influencing population change.

12. Discuss the economic importance of bacteria. Give examples where necessary.

13. Discuss the skin as a sensory organ in mammals.