3. Which of the following cannot increase metabolic rate? A. Reading B. Sleeping C. Talking D. Jogging

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1 Topic 4: Enzymes and metabolism 1. An is only required in a small amount because A. its shape is specific. B. it speeds up both forward and backward reactions. C. it is made of proteins. D. it is not consumed in the reaction. 2. Enzymes can be denatured by heat because they A. Need optimal temperature to work B. Are active in cold only C. Are structurally changed in high temperature D. Are biological catalysts 3. Which of the following cannot increase metabolic rate? A. eading B. Sleeping C. Talking D. Jogging 4. Which of the following are examples of catabolism? (1) amino acid --> protein (2) glucose --> water + carbon dioxide (3) lipid --> glycerol + fatty acid A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 5. Seeds produce some s when they germinate. Which of the following is the main function of these s? A. to synthesise starch from sugars for storage B. to increase the rate of water absorption in the root C. to break down insoluble food into soluble forms D. to carry out photosynthesis 6. When hydrogen peroxide solution is added to a wound for sterilization, bubbles evolve

2 rapidly from the wound. Which of the following is a correct explanation of the phenomenon? A. The red blood cells contains catalase B. The haemoglobin liberates oxygen. C. The hydrogen peroxide increases the respiratory rate of the wounded tissues. D. Carbon dioxide is evolved from the wounded tissue. Directions: Questions 7-11 refer to the diagram below, which is a diagrammatic representation of an catalysed reaction. P Q S P Q S 7. Which of the following substances can be used again? A. P B. Q C. D. S 8. Which of the following statement can be deduced from the diagram? (1) Enzyme action is specific. (2) The reaction is reversible. (3) Enzymes are inactive at low temperatures. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 9. Which of the following is not explained by the diagram? A. Enzymes can be reused. B. Enzymes is specific C. Enzymes reaction is reversible D. eaction rate is speeded up. 10. Which of the following enzymatic reactions can be represented by the diagram? A. Formation of fat B. formation of lactose

3 C. Formation of sucrose D. Formation of protein 11. What would happen when an with an optimum ph of 8.5 is added to a solution with a ph of 4? (1) The may be denatured. (2) The would be lower at ph 4 than ph 8.5. (3) The would be the same at both ph values. A. (1) only B. (1) and (2) only C. (1) and (3) only D. (2) and (3) only Directions: Questions below refer to the apparatus below which is used to compare the activities of the catalase extracted from different tissues. The action of catalase is as follow: 12. What are P, Q and at the beginning of the experiment P Q A. H 2 O 2 H 2 O 2 catalase B. H 2 O 2 H 2 O catalase C. catalase H 2 O H 2 O 2 D. catalase H 2 O 2 H 2 O 13. How can the reaction rate be measured? A. Measure the amount of gas collected in the first 30 seconds B. Measure the amount of gas collected when the reaction has completed.

4 C. Measure the amount of H 2 O 2 left in the flask. D. Measure the amount of water formed in the flask. 14. Which of the following is not a precaution of the experiment? A. All joints must be air-tight B. The amount of extracted added each time must be the same/ C. The amount of H 2 O 2 used each time must be the same. D. The tap must be kept open during experiment. 15. Which of the following graphs shows the effect of on? A. B. C. D. 16. The graph below shows the reaction rate of an without inhibition and that of the same in the presence of an inhibitor. Which curve represents the effect of a non-competitive inhibitor?

5 ate of reaction (1) no inhibition (2) (3) (4) A. (1) B. (2) C. (3) D. (4) Substrate 17. In an investigation to determine the effect of temperature on the of an, the time for all the to disappear from a standard solution was recorded. Which graph shows the results of this investigation? Directions: Questions 18 to 20 refer to the experiment below. TEST 1: 1 g of freshly ground liver was placed in a test tube with 1 cm3 of hydrogen

6 peroxide. A gas was formed. The gas re-lit a glowing splint TEST 2: 1 g of ground liver was boiled. When fresh hydrogen peroxide was added to the boiled liver, no gas was formed. TEST 3: Ground liver treated with strong acid produced results similar to those obtained in test 2. TEST 4: Ground liver treated with strong alkali produced results similar to those obtained in test A hypothesis about in liver is being tested. The hypothesis is that the is affected by A. acids, alkalis, boiling and hydrogen peroxide. B. acids, alkalis and hydrogen peroxide. C. acids, alkalis and boiling. D. grinding the liver. 19. Which of the following test tubes was the control for the experiment? A. the one containing boiled liver and hydrogen peroxide B. the one containing freshly ground liver and hydrogen peroxide C. the one containing liver treated with alkali D. the one containing liver treated with acid 20. Which test(s) showed that the reaction was controlled by an? A. test 1 only B. test 1 and test 2 only C. test 2, test 3 and test 4 only D. test 1, test 2, test 3 and test Which of the following is/are the advantage(s) of using s in industrial processes? (1) Can reduce the production of unwanted products (2) Only small amount is required (3) Can work well in low temperature (4) Does not need extreme and expensive conditions such as very high temperature or pressure. A. (1) and (2) B. (1), (2) and (3) C. (2), (4) D. (1), (2) and (4)