CHEM 210 Biochemistry Module 3
Exam (2024/2025) – Portage Learning
Questions and Verified Answers |
100% Guarantee Pass
Multiple-Choice Questions (1–35)
Question 1: What is the primary function of an enzyme?
A) Store energy
B) Catalyze biochemical reactions
C) Provide structural support
D) Transport molecules
Answer: B) Catalyze biochemical reactions
Rationale: Enzymes lower activation energy to speed up biochemical reactions without being
consumed.
Question 2: Which term describes the molecule an enzyme acts upon?
A) Cofactor
B) Substrate
C) Coenzyme
D) Inhibitor
Answer: B) Substrate
Rationale: The substrate binds to the enzyme’s active site for catalysis.
Question 3: What is the active site of an enzyme?
A) The region that binds cofactors
B) The region where substrates bind
C) The region that stabilizes the enzyme
D) The region that denatures the enzyme
Answer: B) The region where substrates bind
Rationale: The active site is where substrates bind and catalysis occurs.
Question 4: Which type of inhibition reduces Vmax but not Km?
A) Competitive
B) Noncompetitive
C) Uncompetitive
D) Mixed
Answer: B) Noncompetitive
Rationale: Noncompetitive inhibitors bind to a site other than the active site, reducing Vmax
without affecting Km.
, Question 5: What does Km represent in enzyme kinetics?
A) Maximum reaction rate
B) Substrate concentration at half Vmax
C) Enzyme concentration
D) Inhibitor affinity
Answer: B) Substrate concentration at half Vmax
Rationale: Km indicates enzyme-substrate affinity, representing the substrate concentration at
half Vmax.
Question 6: Which model describes enzyme-substrate binding as a precise fit?
A) Induced fit model
B) Lock and key model
C) Allosteric model
D) Cooperative model
Answer: B) Lock and key model
Rationale: The lock and key model suggests the substrate fits the active site like a key in a lock.
Question 7: What is a coenzyme?
A) A protein that enhances enzyme activity
B) A non-protein molecule required for enzyme activity
C) An enzyme inhibitor
D) A substrate analog
Answer: B) A non-protein molecule required for enzyme activity
Rationale: Coenzymes, like NAD+, assist enzymes by transferring groups or participating in
reactions.
Question 8: Which factor increases enzyme activity?
A) Extreme pH
B) High temperature
C) Optimal substrate concentration
D) Denaturation
Answer: C) Optimal substrate concentration
Rationale: Optimal substrate concentration maximizes enzyme activity until saturation occurs.
Question 9: What is Vmax in enzyme kinetics?
A) Substrate concentration at half activity
B) Maximum enzyme concentration
C) Maximum reaction rate
D) Minimum reaction rate
Answer: C) Maximum reaction rate
Rationale: Vmax is the maximum rate of an enzyme-catalyzed reaction when substrate is
saturated.
Question 10: Which type of inhibitor competes with the substrate for the active site?
A) Noncompetitive
B) Competitive
Exam (2024/2025) – Portage Learning
Questions and Verified Answers |
100% Guarantee Pass
Multiple-Choice Questions (1–35)
Question 1: What is the primary function of an enzyme?
A) Store energy
B) Catalyze biochemical reactions
C) Provide structural support
D) Transport molecules
Answer: B) Catalyze biochemical reactions
Rationale: Enzymes lower activation energy to speed up biochemical reactions without being
consumed.
Question 2: Which term describes the molecule an enzyme acts upon?
A) Cofactor
B) Substrate
C) Coenzyme
D) Inhibitor
Answer: B) Substrate
Rationale: The substrate binds to the enzyme’s active site for catalysis.
Question 3: What is the active site of an enzyme?
A) The region that binds cofactors
B) The region where substrates bind
C) The region that stabilizes the enzyme
D) The region that denatures the enzyme
Answer: B) The region where substrates bind
Rationale: The active site is where substrates bind and catalysis occurs.
Question 4: Which type of inhibition reduces Vmax but not Km?
A) Competitive
B) Noncompetitive
C) Uncompetitive
D) Mixed
Answer: B) Noncompetitive
Rationale: Noncompetitive inhibitors bind to a site other than the active site, reducing Vmax
without affecting Km.
, Question 5: What does Km represent in enzyme kinetics?
A) Maximum reaction rate
B) Substrate concentration at half Vmax
C) Enzyme concentration
D) Inhibitor affinity
Answer: B) Substrate concentration at half Vmax
Rationale: Km indicates enzyme-substrate affinity, representing the substrate concentration at
half Vmax.
Question 6: Which model describes enzyme-substrate binding as a precise fit?
A) Induced fit model
B) Lock and key model
C) Allosteric model
D) Cooperative model
Answer: B) Lock and key model
Rationale: The lock and key model suggests the substrate fits the active site like a key in a lock.
Question 7: What is a coenzyme?
A) A protein that enhances enzyme activity
B) A non-protein molecule required for enzyme activity
C) An enzyme inhibitor
D) A substrate analog
Answer: B) A non-protein molecule required for enzyme activity
Rationale: Coenzymes, like NAD+, assist enzymes by transferring groups or participating in
reactions.
Question 8: Which factor increases enzyme activity?
A) Extreme pH
B) High temperature
C) Optimal substrate concentration
D) Denaturation
Answer: C) Optimal substrate concentration
Rationale: Optimal substrate concentration maximizes enzyme activity until saturation occurs.
Question 9: What is Vmax in enzyme kinetics?
A) Substrate concentration at half activity
B) Maximum enzyme concentration
C) Maximum reaction rate
D) Minimum reaction rate
Answer: C) Maximum reaction rate
Rationale: Vmax is the maximum rate of an enzyme-catalyzed reaction when substrate is
saturated.
Question 10: Which type of inhibitor competes with the substrate for the active site?
A) Noncompetitive
B) Competitive
