BioChem 210 Exam Module 3
Questions and Ansẉers
2026\2027 update
1. Which of the following best describes the function of an enzyme?
A) It increases the rate of a reaction by increasing the activation
energy.
B) It decreases the rate of reaction by lowering the activation energy.
C) It increases the rate of a reaction by lowering the activation
energy.
D) It alters the equilibrium constant of a reaction.
Answer: C
2. Enzymes are highly specific in their action. The region of an
enzyme where the substrate binds and the reaction occurs is called
the:
A) Allosteric site
B) Active site
C) Catalytic cavity
D) Substrate pocket
Answer: B
3. Which model suggests that the active site of an enzyme is a rigid,
perfectly fitted shape for the substrate?
A) Induced fit model
B) Lock and key model
,C) Transition state model
D) Allosteric model
Answer: B
4. The "induced fit" model of enzyme action proposes that:
A) The enzyme is rigid and only binds a perfectly matching
substrate.
B) The active site is flexible and changes conformation to snugly fit
the substrate.
C) The substrate is permanently altered upon binding.
D) Enzymes require a cofactor to induce a fit.
Answer: B
5. An organic molecule that is tightly bound to an enzyme and is
required for its activity is termed a:
A) Cofactor
B) Coenzyme
C) Prosthetic group
D) Apoenzyme
Answer: C
6. An enzyme without its necessary cofactor or coenzyme is called
a(n):
A) Holoenzyme
B) Apoenzyme
C) Zymogen
, D) Allosteric enzyme
Answer: B
7. Which of the following is a common coenzyme derived from a B
vitamin?
A) NAD+ (derived from Niacin)
B) ATP
C) Glucose
D) Hemoglobin
Answer: A
8. According to the Michaelis-Menten equation, the velocity of an
enzyme-catalyzed reaction is equal to half of Vmax when:
A) [S] = Km
B) [S] = Vmax
C) [S] = 1/2 Km
D) [S] = 2 Km
Answer: A
9. The Michaelis constant (Km) is defined as:
A) The maximum velocity of a reaction.
B) The substrate concentration at which the reaction rate is half of
Vmax.
C) The turnover number of an enzyme.
D) The affinity of the enzyme for a competitive inhibitor.
Answer: B
Questions and Ansẉers
2026\2027 update
1. Which of the following best describes the function of an enzyme?
A) It increases the rate of a reaction by increasing the activation
energy.
B) It decreases the rate of reaction by lowering the activation energy.
C) It increases the rate of a reaction by lowering the activation
energy.
D) It alters the equilibrium constant of a reaction.
Answer: C
2. Enzymes are highly specific in their action. The region of an
enzyme where the substrate binds and the reaction occurs is called
the:
A) Allosteric site
B) Active site
C) Catalytic cavity
D) Substrate pocket
Answer: B
3. Which model suggests that the active site of an enzyme is a rigid,
perfectly fitted shape for the substrate?
A) Induced fit model
B) Lock and key model
,C) Transition state model
D) Allosteric model
Answer: B
4. The "induced fit" model of enzyme action proposes that:
A) The enzyme is rigid and only binds a perfectly matching
substrate.
B) The active site is flexible and changes conformation to snugly fit
the substrate.
C) The substrate is permanently altered upon binding.
D) Enzymes require a cofactor to induce a fit.
Answer: B
5. An organic molecule that is tightly bound to an enzyme and is
required for its activity is termed a:
A) Cofactor
B) Coenzyme
C) Prosthetic group
D) Apoenzyme
Answer: C
6. An enzyme without its necessary cofactor or coenzyme is called
a(n):
A) Holoenzyme
B) Apoenzyme
C) Zymogen
, D) Allosteric enzyme
Answer: B
7. Which of the following is a common coenzyme derived from a B
vitamin?
A) NAD+ (derived from Niacin)
B) ATP
C) Glucose
D) Hemoglobin
Answer: A
8. According to the Michaelis-Menten equation, the velocity of an
enzyme-catalyzed reaction is equal to half of Vmax when:
A) [S] = Km
B) [S] = Vmax
C) [S] = 1/2 Km
D) [S] = 2 Km
Answer: A
9. The Michaelis constant (Km) is defined as:
A) The maximum velocity of a reaction.
B) The substrate concentration at which the reaction rate is half of
Vmax.
C) The turnover number of an enzyme.
D) The affinity of the enzyme for a competitive inhibitor.
Answer: B
