JAMB Biology Questions on Enzymes: Characteristics, Classification and Functions

The following questions have been set to test students’ understanding of enzymes, their characteristics, classification, and functions in digestion. Enzymes are biochemical catalysts that speed up or slow down the rate of metabolic reactions in living organisms without being used up in the process. These questions are structured in an objective format to help students prepare for examinations and to improve their logical understanding of how enzymes function in digestion.

Objective Questions on Enzymes

1. Enzymes are described as biological catalysts because they
   A. are used up during reactions
   B. speed up chemical reactions in living cells
   C. stop all metabolic activities
   D. destroy food substances
2. One major characteristic of enzymes is that they are mainly composed of
   A. fats
   B. proteins
   C. minerals
   D. carbohydrates
3. The substance on which an enzyme acts is known as
   A. activator
   B. substrate
   C. product
   D. catalyst
4. Enzymes usually function best at an optimum temperature of about
   A. 10°C
   B. 25°C
   C. 37°C
   D. 80°C
5. Enzymes are usually destroyed when heated above
   A. 30°C
   B. 40°C
   C. 60°C
   D. 100°C
6. Which of the following best explains enzyme specificity?
   A. One enzyme can digest all types of food
   B. Each enzyme acts on a particular substrate
   C. Enzymes work only in plants
   D. Enzymes stop digestion
7. Which of the following enzymes digests carbohydrates?
   A. Lipase
   B. Protease
   C. Amylase
   D. Pepsin
8. Lipases are enzymes that break down
   A. proteins
   B. starch
   C. fats and oils
   D. cellulose
9. Proteases are enzymes responsible for digesting
   A. proteins
   B. fats
   C. vitamins
   D. minerals
10. Which enzyme converts starch to maltose in the mouth?
    A. Trypsin
    B. Ptyalin
    C. Lipase
    D. Rennin
11. The enzyme that coagulates milk protein in the stomach is
    A. pepsin
    B. trypsin
    C. rennin
    D. amylase
12. Pepsin converts proteins into
    A. amino acids
    B. fatty acids
    C. peptones
    D. glucose
13. Trypsin is produced by the
    A. liver
    B. pancreas
    C. stomach
    D. salivary gland
14. Lipase converts fats and oils into
    A. glucose and fructose
    B. amino acids
    C. fatty acids and glycerol
    D. maltose and sucrose
15. Which enzyme converts polypeptides into amino acids?
    A. Erepsin
    B. Rennin
    C. Amylase
    D. Ptyalin
16. The enzyme that converts maltose to glucose in the small intestine is
    A. lactase
    B. maltase
    C. sucrase
    D. lipase
17. Sucrase converts sucrose into
    A. glucose and fructose
    B. glucose and maltose
    C. amino acids
    D. fatty acids
18. Lactase helps in the digestion of
    A. starch
    B. lactose
    C. proteins
    D. fats
19. Enzymes can be inactivated by chemicals known as
    A. activators
    B. inhibitors
    C. substrates
    D. products
20. Which of the following is an example of an enzyme inhibitor?
    A. Oxygen
    B. Cyanide
    C. Water
    D. Carbon dioxide
21. Digestive enzymes mainly function
    A. inside the nucleus
    B. outside the body
    C. in the alimentary canal
    D. in the bloodstream
22. The enzyme produced by the pancreas that digests starch in the duodenum is
    A. pepsin
    B. amylase
    C. rennin
    D. maltase
23. A small quantity of enzyme can digest a large amount of food because enzymes
    A. multiply during digestion
    B. are not destroyed after reaction
    C. increase body temperature
    D. change into food
24. The enzyme that converts sucrose into glucose and fructose is found in the
    A. stomach
    B. mouth
    C. small intestine
    D. liver
25. Digestive enzymes are classified mainly based on
    A. their color
    B. the food they digest
    C. the size of the enzyme
    D. the temperature of the body

Answers

1. B
2. B
3. B
4. C
5. C
6. B
7. C
8. C
9. A
10. B
11. C
12. B
13. C
14. C
15. A
16. B
17. A
18. B
19. B
20. B
21. C
22. B
23. B
24. C
25. B