10 questions in 10 minutes
1. The synthesis of complex biological molecules from simpler molecules is called ...
  • A. metabolism
  • B. anabolism
  • C. catabolism
  • D. production

 

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

enzyme structure
Which type of biological molecule is catalase?
  • A. Carbohydrate
  • B. Fatty Acid
  • C. Protein
  • D. Nucleic Acid

3. Which statements are true with regards to the enzymes involved in DNA replication?

I. Molecular motion is necessary for a substrate molecule and an active site to come together.
II. The substrate molecule is large, limiting its movement during interactions with enzymes.
III. Enzymes are immobilized by being embedded in membranes, restricting their movement during interactions with substrates.
  • A. I only
  • B. II only
  • C. I and II only
  • D. I, II, and III

4. 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

5. A student is studying enzyme kinetics and is comparing the Lock and Key model with the Induced Fit model.

induced fit model - wikimedia

Which of the following statements best explains why the Induced Fit model is considered more accurate?

 Thomas Shafee CC BY-SA 4.0
  • A. The Induced Fit model takes into account the three-dimensional structure of enzymes and substrates, including the precise bond angles and lengths that occur upon substrate binding.
  • B. The Lock and Key model accurately represents the conformational changes that occur in enzymes when a substrate binds.
  • C. The Induced Fit model emphasizes the specificity of the enzyme-substrate interaction based on the complementary nature of their shapes.
  • D. The Lock and Key model fails to account for the dynamic nature of enzymes and their ability to adapt to the substrate.

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

  
6. 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

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

  
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 fewer 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 statements best explains the relationship between enzymes and the activation energy of a reaction?

  • A. Enzymes lower the activation energy required to break bonds within the substrate.
  • B. Enzymes increase the activation energy required to break bonds within the substrate.
  • C. Bonds in the enzyme are broken thus increasing the activation energy.
  • D. Enzymes directly provide the energy required to break bonds within the substrate.