Enzyme Catalysis Quiz Questions

10 Questions | Total Attempts: 698

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Enzyme Quizzes & Trivia

Questions and Answers
  • 1. 
    Which of the following statements about the active site of an enzyme is correct?
    • A. 

      The active site of an enzyme binds the substrate of the reaction it catalyses more tightly than it does the transition state intermediate

    • B. 

      The active site of an enzyme binds the substrate of the reaction it catalyses less tightly than it does the transition state intermediate.

    • C. 

      The active site of an enzyme binds the product of the reaction it catalyses more tightly than it does the transition state intermediate.

    • D. 

      The active site of an enzyme is complementary to the substrate of the reaction it catalyses

  • 2. 
    Which of the following statements about the nature of enzyme catalysis is correct?
    • A. 

      An enzyme cannot change the equilibrium position of the reaction it catalyses but it lowers the energy of activation of that reaction.

    • B. 

      An enzyme can change the equilibrium position of the reaction it catalyses by lowering the energy of activation of that reaction.

    • C. 

      An enzyme can lower the energy of activation of the reaction it catalyses by increasing the molecular collisions between the molecules.

    • D. 

      An enzyme lowers the free energy difference between substrate(s) and product(s) but it cannot change the equilibrium position of the reaction it catalyses.

  • 3. 
    Which of the following statements about Michaelis-Menten kinetics is correct?
    • A. 

      Km, the Michaelis constant, is defined as the concentration of substrate required for the reaction to reach maximum velocity.

    • B. 

      Km, the Michaelis constant, is defined as the dissociation constant of the enzyme-substrate complex.

    • C. 

      Km, the Michaelis constant, is a measure of the affinity the enzyme has for its substrate.

    • D. 

      Km, the Michaelis constant, is expressed in terms of the reaction velocity.

  • 4. 
    Which of the following statements about the competitive inhibition of an enzyme-catalyzed reaction is correct?
    • A. 

      A competitive inhibitor and substrate can bind simultaneously to the enzyme.

    • B. 

      The Vmax and Km (Michaelis constant) for a reaction are unchanged in the presence of a competitive inhibitor.

    • C. 

      The Km for a reaction remains unchanged in the presence of a competitive inhibitor.

    • D. 

      The Vmax for a reaction remains unchanged in the presence of a competitive inhibitor.

  • 5. 
    Which of the following statements about the mechanism of allosteric control of enzyme activity is correct?
    • A. 

      Allosteric enzymes are typically single-subunit enzymes.

    • B. 

      Allosteric enzymes show greater sensitivity to changes in substrate concentration compared to classical type enzymes with hyperbolic kinetics.

    • C. 

      Allosteric enzymes show Michaelis-Menten kinetics.

    • D. 

      Allosteric enzymes show reduced sensitivity to changes in substrate concentration compared to classical type enzymes with hyperbolic kinetics.

  • 6. 
    Which of the following statements about the nature of enzyme catalysis is correct?
    • A. 

      He rate of formation of the transition state intermediate determines the overall free energy change of the reaction.

    • B. 

      The active site of an enzyme is perfectly complementary to the substrate in its ground state.

    • C. 

      The rate of formation of the transition state intermediate determines the overall reaction rate.

    • D. 

      Natural substrates bind to enzymes more tightly than transition state analogues

  • 7. 
    Which of the following statements about competitive inhibition of an enzyme-catalyzed reaction is correct?
    • A. 

      Competitive inhibition can be overcome by the addition of large amounts of substrate to a reaction.

    • B. 

      The addition of large amounts of substrate to a reaction cannot overcome the effect of a competitive inhibitor.

    • C. 

      A competitive inhibitor can bind to the enzyme-substrate complex.

    • D. 

      The Vmax of a reaction decreases in the presence of a competitive inhibitor.

  • 8. 
    The fastest enzymes is 
    • A. 

      DNA gyrase

    • B. 

      DNA polymerase

    • C. 

      Carbonic unhydrase

    • D. 

      Pepsin

  • 9. 
    Blocking of enzyme action by blocking its active sites is
    • A. 

      Allosteric inhibition

    • B. 

      Feedback inhibition

    • C. 

      Competitive inhibition

    • D. 

      Non-competitive inhibition

  • 10. 
    An example of competitive inhibition of an enzyme is the inhibition of
    • A. 

      Succinic dehydrogenase by malonic acid

    • B. 

      Cytochrome oxidase by cyanide

    • C. 

      Hexokinase by glucose-6-phosphate

    • D. 

      Carbonic anhydrase by carbon dioxide

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