BIOLOGY HEALTH SCIENCES 2024 NESA QUESTION AND ANSWER
NESA EXAM 2024 QUESTIONNAIRE
Section A: Attempt all questions. (55 marks)
1) Which of the following blood cells contains haemoglobin? (1 mark)
a) Lymphocytes.
b) Phagocytes.
c) Red blood cells.
d) Platelets.
2) What is the function of the cornified layer of the epidermis of the human skin?
(Choose the correct answer.) (1 mark)
a) Temperature regulation through sweating.
b) Perception of sensation of temperature, pain and pressure.
c) Synthesis of Vitamin D.
3) Which acid is produced in the human muscles when there is no enough oxygen?
(Choose the correct answer.) (1 mark)
a) Lactic acid.
b) Hydrochloric acid.
c) Citric acid.
d) Ascorbic acid.
4) Which of the statements below is not biologically correct? (1 mark)
a) All mammals are vertebrates.
b) Frog’s body is moist or rough skin.
c) Bird's have feathers
d) Amphibians have scale
5) Which one of the following is not a function of joints? (1 mark)
a) Articulations.
b) Allows bone growth.
c) Enables mobility.
d) Supports body.
6) Complete the following table with the corresponding type of contraceptive method:
hormonal or non-hormonal or barrier. (5 marks)
Method Type
Spermicide
Condom
Implant
IUD
Pills
7) State whether each of the following statements is true or false (6 marks)
a) Mutations cannot be caused by copying errors in the genetic
material during cell division.
b) Mutations can be caused by environmental changes.
c) Mutations can lead to death.
d) Albinos are results of mutation in humans.
e) Genotypic variations are visible.
f) Phenotypic variations are visible.
8) Fill the blank spaces in the paragraph below with a word from the following list:
meiosis,
fertilization, parent cells, haploid, diploid, gametes. One word can be used more than
once. Write the full paragraph and underline the added word. (8 marks)
The process of meiosis produces unique reproductive cells called ……………. which
have half the number of chromosomes compared to the parent cell. During
…………..., the fusion of gametes from two individuals restores the…………
condition. Gametes are………... (containing only one set of chromosomes) while
the zygote is ……..……. (containing two sets of chromosomes). Thus, sexually
reproducing organisms alternate between haploid and diploid stages. In sexual
reproduction, two individuals produce ……….. offsprings that have
characteristics from both parents. The gametes are produced from………..via the
process called ………..
9) Match the following blood cells with their functions:
Blood component Function
White blood cells. . Defend the body against pathogens
Red blood cells Clotting of blood
Platelets Transport of respiratory gases
Etc......
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Section A
1. Which of the following blood cells contains haemoglobin?
-Answer: Red blood cells.
-Description: Red blood cells contain haemoglobin, a protein that binds to oxygen and transports it throughout the body.
2. What is the function of the cornified layer of the epidermis of the human skin?
- Answer: Prevention of uncontrolled water loss by evaporation.
- Description: The cornified layer acts as a barrier to prevent excessive water loss from the body through evaporation.
3. Which acid is produced in the human muscles when there is not enough oxygen?
- Answer: Lactic acid.
- Description: Lactic acid is produced during anaerobic respiration when oxygen levels are low, leading to muscle fatigue.
4. Which of the statements below is not biologically correct?
- Answer: Amphibians have scales.
- Description: Amphibians do not have scales; they have moist, smooth skin. Reptiles, on the other hand, have scales.
5. Which one of the following is not a function of joints?
- Answer: Allows bone growth.
- Description: Joints facilitate movement and articulation but do not directly contribute to bone growth.
6. Complete the following table with the corresponding type of contraceptive method:
Method Type
Spermicide Non-hormonal
Condom Barrier
Implant Hormonal
IUD Non-hormonal
Pills Hormonal
7. State whether each of the following statements is true or false:
- a) False: Mutations can be caused by copying errors in the genetic material during cell division.
- b) True: Mutations can be caused by environmental changes.
- c) True: Mutations can lead to death.
- d) True: Albinos are results of mutation in humans.
- e) False: Genotypic variations are not visible; they are genetic.
- f) True: Phenotypic variations are visible.
8. Fill the blank spaces in the paragraph below:
- Answer:
The process of meiosis produces unique reproductive cells called "gametes"which have half the number of chromosomes compared to the parent cell. During "fertilization", the fusion of gametes from two individuals restores the "diploid" condition. Gametes are "haploid" (containing only one set of chromosomes) while the zygote is "diploid" (containing two sets of chromosomes). Thus, sexually reproducing organisms alternate between haploid and diploid stages. In sexual reproduction, two individuals produce diploid offspring that have characteristics from both parents. The gametes are produced from parent cells via the process called meiosis.
9. Match the following blood cells with their functions:
Blood component Function
1.White blood cells = Defend the body against pathogens
2.Red blood cells = Transport of respiratory gases
3. Platelets = Clotting of blood
10. Write Yes if the statement is correct and No if it is wrong:
- a) Yes: ATP is released in the mitochondrion.
- b) Yes : Aerobic respiration releases more energy than anaerobic respiration.
- c) No : Cellular respiration occurs in both animal and plant cells.
11. Identify the parts of the human reproductive system in which each of the following gametes is produced:
- a) Sperm cell: Testes.
- b) Ovum: Ovaries.
12. The age of four individuals is as follows:
- a) Answer: The 3-year-old boy needs more milk.
- b) Reason: Children require more calcium and nutrients for growth and development.
- c) Reason: A pregnant mother needs more iron to support the increased blood volume and to provide for the developing fetus.
13. Athletes are normally given glucose and not sucrose. Give a reason for this.
- Answer: Glucose is a simple sugar that can be quickly absorbed and used by the body for energy, whereas sucrose needs to be broken down into glucose and fructose before it can be utilized.
14. What is the basic measure you can take to protect yourself from contracting a disease?
- Answer: Practice good hygiene, such as regular handwashing and avoiding contact with infected individuals.
15. Explain why farmers who grow cereals such as wheat, barley, and rice must ensure that plants grow close to each other.
- Answer: Growing plants close together helps reduce soil erosion, conserve moisture, and maximize the use of available space and nutrients.
16. In your opinion, how would you deal with sexual assault?
- Answer: Report the incident to authorities, seek medical and psychological support, and ensure the victim is protected and supported throughout the process.
17. Why should industrial plants treat their waste water before dumping it in water bodies?
- Answer: Treating wastewater removes harmful chemicals and pollutants, preventing water pollution and protecting aquatic life and human health.
18. Fill in the blank spaces:
- a) Antigens bind at the "antigen-binding" site forming "antigen-antibody" complexes.
- b) "Natural" immunity is a naturally acquired immunity.
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Section B
19. a) How can we help someone with cholera?
- Answer: Provide oral rehydration solutions (ORS) to prevent dehydration and seek medical treatment immediately.
- b) Suggest any four daily practices to ensure good health:
1. Eat a balanced diet.
2. Exercise regularly.
3. Get adequate sleep.
4. Maintain personal hygiene.
20. Describe the negative impact of monoculture system to the biological diversity in an ecosystem.
- Answer: Monoculture reduces biodiversity by favoring a single crop, which can lead to soil depletion, increased vulnerability to pests, and loss of habitat for other species.
21. Answer the following in relation to blood:
a) What is blood plasma?
- Answer: Blood plasma is the liquid component of blood that carries cells, nutrients, and waste products.
- b) Give the role of blood plasma:
- Answer: It transports nutrients, hormones, and waste products, and helps maintain blood pressure and pH balance.
- c) The ABO blood group system has four blood groups. Name them:
- Answer: A, B, AB, and O.
- d) Name this factor:
- Answer: Rh factor.
- e) Suggest a reason why it is important to know a person’s blood group:
- Answer: To ensure compatibility during blood transfusions.
- f) What is the function of platelets in blood?
- Answer: Platelets help in blood clotting to prevent excessive bleeding.
22. A man whose blood group is A marries a woman whose blood group is B. If one of their children has blood group O:
- a) What are the genotypes of the parents?
- Answer: Both parents are heterozygous (AO and BO).
- b) Use a Punnett square to determine the possible phenotypes of the other children:
- Answer: The possible phenotypes are A, B, AB, and O in a 1:1:1:1 ratio.
23. a) What do you understand by the term mitosis?
- Answer: Mitosis is the process of cell division that results in two identical daughter cells.
- b) “Mitosis is essential in all living organisms”. Give reasons to support this statement:
1. It allows for growth and development.
2. It enables tissue repair and regeneration.
3. It ensures genetic consistency in asexual reproduction.
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Section C
24. Assume you are performing an experiment to demonstrate osmosis:
- a) Enumerate the apparatus and chemicals you may use in your demonstration:
- Answer: Beaker, dialysis tubing, sucrose solution, distilled water, and a measuring cylinder.
- b) Suggest a control that you might use in this activity:
- Answer: Use distilled water on both sides of the dialysis tubing.
- c) State the result(s) of the demonstration:
- Answer: Water will move into the dialysis tubing containing the sucrose solution.
- d) Briefly explain the result(s):
- Answer: Osmosis causes water to move from an area of low solute concentration to an area of high solute concentration
.
- e) Suggest how storing food in salty water prevents the growth of bacteria or fungi on the stored food:
- Answer: The high salt concentration creates a hypertonic environment, causing bacteria and fungi to lose water and die.
- f) Apart from the method described in (e) above, suggest any other way of preventing food from spoilage:
- Answer: Refrigeration or freezing.
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