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Biology µIB
2.5 Enzymes
10 quick questions



Essential Idea: Enzymes control the metabolism of the cell.

10 minutes maximum! (can you do it in 5?)


Q1-3: This image is of the enzyme catalase which breaks down hydrogen peroxide in living tissues releasing oxygen and water.

enzyme structure

1. Which type of biological molecule is catalase?
  • A. Carbohydrate
  • B. Fatty Acid
  • C. Protein
  • D. Nucleic Acid
2. State the name of the substrate that fits into the active site.
  • A. Catalase
  • B. Water
  • C. Protein
  • D. Hydrogen peroxide
3. When catalase is heated to over 60oC for several minutes, what happens to the reaction when the catalase is added to hydrogen peroxide?
  • A. No oxygen is produced as the active site has denatured
  • B. No oxygen is produced as the active site is blocked
  • C. Lots of oxygen is produced as the reaction is going so fast
  • D. Lots of oxygen is produced as the active site is denatured

Q4-6: The graph below shows how temperature affects the rate of reaction caused by an enzyme such as catalase:

graph showing the effect of temperature on rate of reaction involving enzymes


4. At X the rate of reaction increases due to ...

  • A. the increased kinetic energy of the substrate molecule
  • B. the increased kinetic energy of the enzyme molecules
  • C. the increased kinetic energy of both the substrate and enzyme molecules
  • D. a decrease in the kinetic energy of both the substrate and enzyme molecules
5. What is happening to the active site of the enzyme in Z?
  • A. It is reformed
  • B. It is denatured
  • C. It is blocked by an inhibitor
  • D. Nothing
6. Which of the following may denature an enzyme?
  • A. An inhibitor
  • B. pH
  • C. Substrate concentration
  • D. Enzyme concentration

Q7-9: A student carried out an experiment to investigate the effect of changing the substrate concentration on the activity of an enzyme. Their data is shown in the graph below:

graph enzyme activity with substrate concentration
(Arbitrary units used)

7. At which concentration are approximately half of the active sites of the enzyme filled at a given time?
  • A. K
  • B. L
  • C. M
  • D. N
8. Why does the graph begin to flatten off at M?
  • A. The enzyme becomes denatured
  • B. An inhibitor is present
  • C. There are few active sites available for the substrate molecules
  • D. The enzyme concentration is high
9. Which of the following must be kept constant throughout the experiment?
  • A. Temperature
  • B. Enzyme concentration
  • C. pH
  • D. All of the above.
10. Which of the following will not be affected by immobilizing an enzyme?
  • A. Optimum temperature of the enzyme
  • B. Rate at which the substrate binds to the active site
  • C. Shape of the active site
  • D. Stability of the enzyme to changes in pH