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: 2008

SECTION A

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

(i) When examining a cell from an unidentified organ of a mouse under an electron microscope, a student found an organelle with infolding in the inner membrane. Which organelle is it? 

1. Golgi body
2. Endoplasmic reticulum
3. Ribosome
4. Mitochondrion
5. Nucleus

(ii)Which of the following statements is true about eukaryotic cells?

1. They lack important organelles like smooth endoplasmic reticulum.
2. They are found in plants only.
3. Nuclear materials are enclosed within a membrane.
4. They are found only in animals.
5. They contain only little water.

(iii)Spitting, coughing and sneezing into a tissue paper are considered as: 

1. Waste disposal methods
2. Risk behaviors of spreading diseases
3. Good manners
4. Environmental pollution
5. A way of killing pathogens in the tissue.

(iv) Mr. and Mrs. Msakanjia, happened to have four children in their marriage. One of them is an albino. What is the possible genotype of Mr. and Mrs. Msakanjia?

1. AA x AA
2. Aa x aa
3. Aa x Aa
4. aa x aa
5. AA x Aa

(v) A mountaineer develops headache, breathlessness, nausea and vomiting on reaching an altitude of above 4000 metres. This is because: 

1. his body system is not given time to adjust to the low oxygen pressure.
2. the atmospheric pressure as well as the supply of oxygen decreases at higher altitude.
3. the increase in the amount of oxygen results into breåthlessness.
4. the atmospheric pressure increases at higher altitude and so does the supply of oxygen.
5. his body system is not given time to relax due to the increase of atmospheric pressure.

(vi) A student planted some seeds in sand. After the radical was fully developed, it was observed that in all seedlings it grew downward horizontally instead of vertically. This indicates that:

1. the sand contained water on one side only.
2. the sand contained large particles which prevented the radical to grow vertically.
3. the force of gravity forced the radical to grow horizontally.
4. it is the nature of radical to grow horizontally always.
5. the concentration of auxin inhibited the radical to grow vertically.

(vii) During the school race Mary experienced an increased rate in breathing.

This is because breathing rate supplies extra:

1. energy required by the active muscle.
2. oxygen required by the active muscle.
3. heat required by the active muscle.
4. enzymes required by the active muscles for respiration.
5. Work required by the muscles for faster running.

(viii)The best way of preventing viral infection is:

1. through biological control.
2. avoiding direct contact with an infected person.
3. killing all viruses.
4. vaccination.
5. by medical treatment.

(ix)Girls circumcision or female genital mutilation is considered to be a:

1. good sexual health practice because it controls prostitution among women.
2. good mental health practice.
3. bad physical harassment to women.
4. bad practice which interferes with sexual health.
5. good practice which prevents spread of HIV/AIDS.

(x)In green grass there are usually large numbers of green grasshoppers than brown grasshoppers. The best explanation is that the:

1. green grasshoppers feel the need of being green to give them protection.
2. predators do not capture green grasshoppers as frequently as brown grasshoppers.
3. green grass makes the brown grasshopper not to be seen by the predators.
4. green grasshoppers obtain enough food from green grass than brown grasshopper.
5. green grass stimulates green grsshoppers to reproduce and increase in number faster than brown grasshoppers.

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

SECTION B

3. (a) (i) The kingdom plantae is divided into different divisions. Mention them.

(ii) Give one example of the plants which are found in each division.

(b) With the use of illustrations differentiate between dicotyled0J10us and monocotyledonous in the following aspects:-

(i)Venation

(ii)Arrangement of vascular tissues in stem.

4 Study the diagram below and answer the questions that follow.

Fig. 1

(a) (i) Using the knowledge of genetics explain what happened to the resultant sex chromosome.

(ii) Mention the possible causes of the above process.

(b) A motor car called Land Cruiser is able to move, uses energy by oxidizing fuel, gives out carbon dioxide and water vapour, requires maintenance and becomes old. Give reasons why it is not classified as a living organism.

5. (a) Most of the people living in Mtakuja village dispose their wastes randomly without taking any precaution.

(i)State the effects of this habit to their health.

(ii)Briefly explain how you would advise them on proper ways of disposing their wastes.

(b) Explain the meaning of the following ecological terms:

(i)Food chain

(ii)Trophic level

6. (a) Explain the following Mendelian traits and give their effect to human beings.

(i)Haemophilia

(ii)Sickle anaemia

(b) In a certain species, two homozygous individuals mated and resulting offspring in Fl was heterozygous with the same phenotype. However in the second filial generation (F2) a new heterozygous phenotype was obtained which looked different from the parents in F1 With the help of genetic diagrams, explain how individuals with different phenotype in F2 were obtained.

7.(a) A group of Form IV students from Manyanya Secondary School had a study visit to Mt. Meru Hospital. They noted a patient with sunken eyes, severe dehydration, weak pulse, deep breathing, vomiting and convulsions.

(i)What could be the possible disease that this patient was suffering from?

(ii)Suggest preventive measures for the disease in 7 (a) (i) above.

(b) AIDS is one of the threatening diseases worldwide. Briefly explain the precautions that must be taken when caring for someone with AIDS.

8. (a) Explain the significance of meiosis in relation to reproduction.

(b) Explain why it is not possible for insect to visit and pollinate wind pollinated flower.

9. (a) The diagram below represents the arrangement of a tube and structures through which oxygen passes as it travels from the atmosphere into the blood of mammals.

Fig. 2

(i)Name the tube represented by the numbers 1, 2, and 3.

(ii)Name the structure represented by number 4.

(iii)Unlike animals, plants have no special organs for gaseous exchange. How then do they carry out gaseous exchange?

(b) (i) Define an ecological pyramid.

(ii) Construct a simple ecological pyramid of members to show different trophic levers.

10. (a) Who is an albino?

(b) Explain the problems faced by albinos under the following guidelines:

(i) Vision

(ii) Exposure to sunlight

(c) Give the genotype of the offspring produced when an albino male marries a female who is heterozygous for albinism.

SECTION C

11.Most of the young people today practice risky behaviours thinking that it is a modern style of life. This is a wrong concept. Discuss the factors which contribute to risky behaviours among young people in the society and their consequences.

12.Human beings have been destructive to the natural environment. One of the effects is global warming. Write an essay on global warming using the following guidelines.

(a) The meaning of global warming.

(b) The gases which contribute to the increase of global warming.

(c) Men's activities which contribute towards global warming.

(d) The effects of global warming.

(e) Measures to be taken to prevent global warming.

13.Some chemical reactions take place inside the living systems. Some of the products given out are harmful if allowed to accumulate; these are known as excretory products. Explain the excretory products in human beings based on the excretory organ involved in each product, where it is produced and its effects to the human body.