Enzymes — Paper 1 · IGCSE Biology (9-1) 0970

10 An experiment was carried out to investigate the effect of pH on enzyme action. The graph shows the results. y-axis x-axis What are the labels for the x-axis and the y-axis? x-axis y-axis A pH rate of reaction B pH time C rate of reaction pH D time pH

1 marks

Answer: A

This question in 0970/11 May/June 2018

38 Some washing powders are called biological washing powders. What is the reason for this? A They contain bacteria. B They contain enzymes. C They contain myriapods. D They contain viruses.

1 marks

Answer: B

This question in 0970/11 May/June 2018

10 The apparatus shown is used for an experiment on starch digestion. Which test-tube contains the most sugar after 20 minutes? A B C D starch starch solution starch solution and salivary solution and salivary amylase amylase water-bath at 15 °C water-bath at 37 °C

1 marks

Answer: D

This question in 0970/12 Oct/Nov 2018

10 Which graph shows the effect of pH on enzyme activity? A B enzyme enzyme activity activity 1 7 14 1 7 14 pH pH C D enzyme enzyme activity activity 1 7 14 1 7 14 pH pH

1 marks

Answer: C

This question in 0970/11 May/June 2019

14 The following statements are about enzymes. 1 enzymes are catalysts 2 enzyme are proteins 3 enzymes are used up during chemical reactions Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 0970/11 May/June 2019

9 What is the definition of an enzyme? A a carbohydrate that acts as a catalyst B a DNA molecule that acts as a catalyst C a fat that acts as a catalyst D a protein that acts as a catalyst

1 marks

Answer: D

This question in 0970/11 May/June 2020

12 The graph shows the effect of pH on the activity of an enzyme. enzyme activity 1 3 5 7 9 11 pH In which part of the alimentary canal would this enzyme be most active? A large intestine B mouth C small intestine D stomach

1 marks

Answer: D

This question in 0970/12 May/June 2020

10 The graph shows the effect of pH on the rate of reaction of an enzyme. rate of reaction 3 4 5 6 7 8 9 pH What does the graph show? A The enzyme is destroyed at pH 9. B The enzyme works best at pH 6. C The rate of reaction halves as the pH changes from pH 5 to pH 7. D The rate of reaction is the same at pH 5 and pH 8.5.

1 marks

Answer: D

This question in 0970/12 Oct/Nov 2020

11 What kind of molecule is an enzyme? A fat B glucose C protein D starch

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2020

10 Starch is digested by amylase in the mouth, but it is not digested in the stomach. What is the reason for this? A All starch digestion is completed in the mouth. B The pH in the stomach is not suitable for the amylase to work. C The starch does not stay in the stomach long enough to be digested. D The temperature in the stomach is not suitable for the amylase to work.

1 marks

Answer: B

This question in 0970/11 May/June 2021

11 Which statement describes a catalyst? A a substance that decreases the rate of a chemical reaction and is not changed by the reaction B a substance that decreases the rate of a chemical reaction and is changed by the reaction C a substance that increases the rate of a chemical reaction and is changed by the reaction D a substance that increases the rate of a chemical reaction and is not changed by the reaction

1 marks

Answer: D

This question in 0970/11 May/June 2021

10 An experiment was carried out to investigate the effect of pH on enzyme action. The graph shows the results. y-axis x-axis What are the labels for the x-axis and the y-axis? x-axis y-axis A pH rate of reaction B pH time C rate of reaction pH D time pH

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2021

11 Four test-tubes were set up as shown in the diagram. In which test-tube is the starch digested most quickly? A B C D water-bath water-bath at 15 °C at 35 °C starch solution starch solution and amylase and amylase starch solution starch solution and boiled amylase and boiled amylase

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2021

10 Some terms used to describe enzyme-controlled reactions are listed. 1 catalyst 2 product 3 protein 4 substrate Which terms describe an enzyme? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

1 marks

Answer: A

This question in 0970/11 May/June 2022

10 Which type of molecule are enzymes made of? A carbohydrates B fats C proteins D vitamins

1 marks

Answer: C

This question in 0970/12 May/June 2022

10 Which statement about enzymes is correct? A They are made of carbohydrates. B Their activity is unaffected by pH. C They are used up during the reaction. D They have a complementary shape to their substrate.

1 marks

Answer: D

This question in 0970/12 Oct/Nov 2022

11 The graph shows the effect of temperature on the activity of an enzyme. enzyme activity 0 10 20 30 40 50 60 70 80 temperature / °C At which temperature is the enzyme most active? A 15 °C B 25 °C C 35 °C D 60 °C

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2022

10 What is true of all enzymes? they are sugars they are most effective at pH 7 0 0O WwW D> x KOK v x v x key v= yes X =no

1 marks

Answer: D

This question in 0970/11 May/June 2023

11 What is the substrate for enzyme X? enzyme X A B C D

1 marks

Answer: D

This question in 0970/11 May/June 2023

10 Which processes depend on the action of enzymes? 1 digestion 2 osmosis 3 respiration A 1 and 2 B 1 and 3 C 1 only D 2 and 3

1 marks

Answer: B

This question in 0970/12 May/June 2023

11 Which diagram of an enzyme, active site and substrate is correct? A B substrate enzyme enzyme active site active site substrate C D substrate enzyme enzyme active site active site substrate

1 marks

Answer: C

This question in 0970/12 May/June 2023

32 In a sperm cell, which structure contains enzymes that can digest the jelly coat of an egg cell? A acrosome B flagellum C mitochondria D nucleus

1 marks

Answer: A

This question in 0970/12 May/June 2023

10 Which changes could cause an enzyme to denature? 1 change in pH 2 change in temperature 3 change in substrate concentration A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2023

11 What is a correct statement about enzymes? A The pH has no effect on the rate of reaction. B They are denatured at low temperatures. C They are made of carbohydrates which have specific shapes. D They speed up chemical reactions.

1 marks

Answer: D

This question in 0970/11 May/June 2024

12 Which statement about enzyme action is correct? A The shape of the enzyme’s active site is complementary to all proteins. B The shape of the enzyme’s active site is complementary to the substrate. C The shape of the substrate’s active site is complementary to the product. D The shape of the substrate’s active site is complementary to the enzyme.

1 marks

Answer: B

This question in 0970/11 May/June 2024

11 Which graph shows the effect of temperature on the activity of an enzyme? A B enzyme enzyme activity activity 0 50 100 0 50 100 temperature / °C temperature / °C C D enzyme enzyme activity activity 0 50 100 0 50 100 temperature / °C temperature / °C

1 marks

Answer: A

This question in 0970/12 May/June 2024

12 Which of these statements about enzymes are correct? 1 enzymes are proteins 2 enzymes are used up during chemical reactions 3 enzymes speed up metabolic reactions A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: C

This question in 0970/12 May/June 2024

30 What is the function of the acrosome in a sperm cell? A The acrosome contains enzymes that digest the jelly coat of an egg cell. B The acrosome is needed for the sperm cell to move. C The acrosome releases energy. D The acrosome stores genetic information.

1 marks

Answer: A

This question in 0970/12 May/June 2024

40 The diagram shows a label found on a container of biological washing powder. Biological washing powder • works at low temperatures • contains protease • contains lipase • keep out of reach of children Which stains does the washing powder remove? food stain food stain food stain food stain containing containing containing containing oil carbohydrates protein fat A ✓ ✓ ✗ ✗ key B ✓ ✗ ✗ ✓ ✓= yes C ✗ ✓ ✓ ✓ ✗= no D ✗ ✗ ✓ ✗

1 marks

Answer: C

This question in 0970/12 May/June 2024

12 Which statements about enzymes are correct? 1 Enzymes are biological catalysts. 2 Enzymes are carbohydrates. 3 Enzymes have an active site. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2024

26 Which graph shows how temperature affects the rate of anaerobic respiration in yeast? A B anaerobic anaerobic respiration respiration rate rate 0 50 0 50 temperature / °C temperature / °C C D anaerobic anaerobic respiration respiration rate rate 0 50 0 50 temperature / °C temperature / °C

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2024

11 The graph shows the activity of three digestive enzymes at differing pH values. X Y Z enzyme activity 1 2 3 4 5 6 7 8 9 10 11 12 pH Which statement is correct? A Enzymes X and Y are both active at pH 7. B Enzymes X and Z are both active at pH 4. C Enzymes Y and Z are both active at pH 4. D Enzymes Y and Z are both active at pH 8.

1 marks

Answer: D

This question in 0970/11 May/June 2025

39 The graph shows how changing the temperature affects the rate of stain removal from clothes, using a biological washing powder. rate at which stains are removed 0 10 20 30 40 50 60 temperature / °C What does the graph suggest about biological washing powders? A Biological washing powders contain enzymes. B Biological washing powders work best at all temperatures above 40 °C. C The optimum temperature for the reaction is between 10 °C and 30 °C. D There is a directly proportional relationship between the temperature used and the rate at which stains are removed.

1 marks

Answer: A

This question in 0970/12 May/June 2025

7 Enzymes are large molecules. Which small molecules are they made from? A amino acids B carbon dioxide and water C fatty acids D sugars

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2025

8 Why does the active site of an enzyme fit with its substrate? A They denature at the same temperature. B They have complementary shapes to each other. C They have the same amount of kinetic energy. D They have the same shape as each other.

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2025

11 The graphs show the effect of pH on the activity of four different digestive enzymes. Which enzyme is most active in the stomach? A B 100 100 percentage percentage activity 50 activity 50 0 0 0 2 4 6 8 10 12 0 2 4 6 8 10 12 pH pH C D 100 100 percentage percentage activity 50 activity 50 0 0 0 2 4 6 8 10 12 0 2 4 6 8 10 12 pH pH

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2025

40 Biological washing powders contain enzymes. Which enzyme removes an oil stain from clothes? A amylase B lipase C pectinase D protease

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2025