Growth - Competence Based Questions With Answers | Form Four

 

15 Competence-Based Questions with Answers

1. What is growth in living organisms?

Answer: Growth is the permanent and irreversible increase in the size, mass, and number of cells of an organism.

2. A farmer notices that a young plant becomes taller and develops more leaves after several weeks. Explain the biological processes responsible for these changes.

Answer: The increase in height and development of new leaves are results of growth. Growth occurs through cell division, followed by cell enlargement and differentiation. Cell division produces new cells, while enlargement increases their size and differentiation allows them to become specialized tissues.

3. Why is cell division important in the growth of organisms?

Answer: Cell division, particularly mitosis, produces new cells. The increase in the number of cells contributes to an increase in the size and mass of an organism. It also replaces old and damaged cells.

4. Two identical seedlings are planted under the same conditions. One is supplied with enough water while the other receives very little water. After two weeks, the first seedling has grown better. Explain why.

Answer: Water is essential for metabolic activities and maintaining cell turgidity. Adequate water allows normal cell expansion and metabolic processes, while water deficiency reduces these processes and therefore slows growth.

5. Explain why nutrients are important for plant growth.

Answer: Plants require mineral nutrients to manufacture proteins, enzymes, chlorophyll and other substances needed for growth. Nutrients also support cell division and the formation of new tissues.

6. Why does a plant growing in darkness usually have weak and elongated shoots?

Answer: In darkness, the plant cannot carry out photosynthesis effectively, so it produces insufficient food for normal growth. The shoot becomes unusually elongated, thin and weak as it grows towards a possible source of light.

7. Mention four factors that affect growth in human beings.

Answer:

i. Genetic factors
ii. Nutrition
iii. Hormones
iv. Diseases

8. Differentiate between growth and development.

Answer: Growth refers to a permanent and irreversible increase in the size, mass or number of cells of an organism. Development refers to progressive changes in the structure, function and abilities of an organism as it becomes mature.

9. A student wants to investigate the effect of water on the growth of seedlings. Describe how the experiment can be carried out.

Answer: The student should use two similar seedlings planted in similar containers containing equal amounts of soil. One seedling should receive adequate water while the other receives a limited amount. Other factors such as light, temperature and soil type should be kept constant. The height of each seedling should be measured regularly and the results compared.

10. Explain how temperature affects growth.

Answer: Temperature affects the activity of enzymes that control metabolic reactions. At very low temperatures, metabolic reactions become slow, reducing growth. At very high temperatures, enzymes may be denatured, also interfering with growth. Therefore, organisms grow best within a suitable temperature range.

11. Why is a balanced diet important for growth in human beings?

Answer: A balanced diet provides the nutrients required for building new tissues, repairing damaged tissues and supplying energy for metabolic activities. Proteins are particularly important for tissue formation and repair, while vitamins and minerals support normal body functions.

12. A child suffers from severe protein deficiency for a long period. Explain how this condition may affect the child's growth.

Answer: Protein deficiency reduces the body's ability to build and repair tissues. As a result, the child may experience stunted growth, poor muscle development and delayed physical development.

13. Mention four hormones that are associated with growth and development in humans.

Answer: i. Growth hormone
ii. Thyroxine
iii. Oestrogen
iv. Testosterone

14. A farmer removes the shoot tip of a young plant, and the plant later stops increasing in height. Explain this observation.

Answer: The shoot tip contains the apical meristem, which consists of actively dividing cells. These cells produce new cells that contribute to the increase in length of the shoot. Removing the shoot tip therefore reduces primary growth in length.

15. “All organisms grow throughout their entire lives.” Do you agree with this statement? Give reasons for your answer.

Answer: No, I do not completely agree. Growth patterns differ among organisms. Many animals reach a maximum size after attaining maturity, whereas plants can continue growing throughout their lives because they possess meristematic tissues capable of continuous cell division.