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 item (i) - (x) choose the correct answer from among the given alternatives and write its letter beside the item number.

(i)An experiment usually tests:

1. application
2. hypothesis
3. method
4. data 
5. evaluation

(ii) Figure 1 shows a palisade cell.

Fig. 1

What structures occur in the regions indicated?

(iii) Which substance in tobacco combines with haemoglobin to prevent the haemoglobin from carrying oxygen?

1. Carbon dioxide
2. Carbon monoxide
3. Nicotine
4. Tar
5. Cellulose fibre

(iv) A plant with variegated leaves was completely destarched by p acing It in a dark cupboard for 48 hours. Black paper was then fixed on one leaf as shown in Figure 2 below and the plant was exposed to the light. After 24 hours which region of the leaf contained starch?

Fig. 2

In which condition must a plant be placed to show that a green plant releases carbon dioxide and why?

(vi) The diagram below (Figure 3) shows a section through an alveolus and through a capillary passing around it.

Fig. 3

How does oxygen move from X to Y? By:

1. Diffusion
2. Osmosis
3. Translocation 
4. Active transport
5. Transpiration

(vii) Study the diagram below carefully (Figure 4).  

Fig. 4

What does A represent?

1. Load (hand and forearm)
2. Effort (flexor of muscular upper arm)
3. Fulcrum (elbow joint)
4. Pulley
5. 1^st class lever

(viii) Which of the following substances is not a waste product in man?

1. Faeces 
2. uric acid
3. sweat
4. Carbon dioxide 
5. urea

(ix) Which hormones produced by the pituitary gland promote ovulation?

1. Follicle stimulating hormone (FSH) and lutenizing hormone (LH)
2. Lutenizing hormone (LH) and progesterone
3. Oestrogen and progesterone
4. Progesterone and follicle stimulating hormone (FSH)
5. Prolactin and progesterone

(x) Which part of the seed grows into the root system of a plant?

1. Cotyledon 
2. mocropyle
3. Plumule 
4. Radical
5. hilum

2. Match the items in List A with the response in List B by writing the letter of the correct response beside the item number

SECTION B

3.(a) Figure 5 shows a red blood cell and a root hair cell.

Figure 5

(i) Select two structures in the root hair cell which are also present in the red blood cell. In each case, state the letter and name of the structure.

(ii) Name one structure which is typical of many plant cells which is not present in the root hair cell.

(b)State one major function of each of the following cells and describe one way in which thCcell is adapted to carry out its function.

(i)Red blood cell:

Function . . . . . . . .

Adaptation ............

(ii)Root hair cell:

Function . . . . . . . .

Adaptation ...........

4.(a) Name parts of the alimentary canal where:

(i)Digestion of starch takes place

(ii)Absorption of the end products of digestion takes place

(b)The graph below (Figure 6) shows changes in pH in the mouth over a period of 10 hours.

(i)What is the pH in the mouth one hour after the meal that was eaten at 7:30 a.m.?

(ii)Suggest the cause of the increase and decrease of pH in the mouth between 8 a.m. and 9 a.m.

(iii)Suggest why the pH change after eating sweets is smaller than after eating meals

Fig. 6

5.(a) How could the body remove or destroy a bacterium that lands:

(i)on the cornea?

(ii)on the hand?

(iii)in the bronchus? (iv) in the stomach?

(b)Explain why it is:

Not healthy to sleep in a closed room with many potted plants.

(ii) Dangerous to sleep in a poorly ventilated room with a charcoal burner on.

6.(a) (i) State the meaning of sexual reproduction. Figure 7 below shows the human male reproductive system.

(ii) Name the part labelled X and state two of its functions.

(b) (i) Birth control can be practiced by surgery. Copy/draw Fig. 7 and mark clearly where such an operation should be carried out in male human beings.

(ii) Name two changes other than those found on the sex organs which result from the effect of sex hormones.

Fig. 7

The following table shows the frequency of human blood groups in a population.

(i)Plot the data in the Table as bar chart on the graph paper provided in your answer booklet.

(ii)What type of variation is illustrated by the data? Give reasons for your answer.

(b) A plant dispersed its seeds naturally. The seedlings formed were examined two weeks later. They were found to differ in height.

Suggest three environment factors which caused the difference.

8.(a) (i) Define immunity.

(ii) Distinguish between natural acquired immunity and artificially acquired immunity.

(b) Name four diseases against which children are immunized.

9.Nitrogen and phosphorus are essential plant growth minerals. They are absorbed from the soil as nitrate and phosphate ions respectively. In fresh waters phosphate ions occur in very small amounts while nitrate ions are normally in excess. As a result itis the changes in the phosphate concentration which promote or inhibit plant growth. Phosphorus is therefore a limiting nutrient.

(a) Name two factors other than nutrients and light that can Ignit plant growth.

(b) Describe an investigation you could carry out to show that phosphorus is a limiting nutrient for water plants.

10.Explain the following observations:

(a) Lighting a shoot from one side makes it bend towards light.

(b) The shoot of a seedling kept in dark and placed sideways (horizontal), grows upwards while its roots grow downwards.

SECTION C

11. State the cause and explain the transmission (where applicable) and preventive measures of the following problems:(a) Meningitis

(b) Cholera

(c) Malaria

(d) Bilharziasis

12. (a) Write an essay on natural resources using the following headings:(a) Meaning of natural resources.

(b) Types of natural resources including two examples of each cas (c) Effects of man's activities on natural resources. (d) Conservation of natural resources.

13. (a) Food preservation is very important in human life. Discuss its importance under the following headings:(a) Need for preservation.

(b) Local food preservation methods and their biological effects.