CHEM 210 Biochemistry Module 2
Questions And Correct Answers
(Verified Answers) Plus Rationales 2025
Q&A | Instant Download PDF
1. Which of the following is not a function of enzymes?
A. Lower activation energy
B. Alter the equilibrium constant
C. Increase reaction rate
D. Provide specificity for substrates
B. Alter the equilibrium constant
Enzymes speed up reactions but do not change the overall
thermodynamics, such as the equilibrium constant.
2. The region of the enzyme where substrate binds is called the:
A. Regulatory site
B. Allosteric site
C. Active site
, D. Inhibitory site
C. Active site
The active site is the specific region where the substrate binds and
the reaction occurs.
3. A coenzyme is:
A. A non-protein organic molecule essential for enzyme activity
B. A metal ion that binds permanently
C. A protein helper of enzymes
D. The same as a zymogen
A. A non-protein organic molecule essential for enzyme activity
Coenzymes are small organic molecules that assist enzymes in
catalysis.
4. Which vitamin is a precursor for NAD⁺/NADP⁺?
A. Vitamin C
B. Niacin
C. Riboflavin
D. Biotin
B. Niacin
Niacin is converted into NAD⁺ and NADP⁺, which function as electron
carriers.
5. In competitive inhibition, the inhibitor:
A. Binds to the enzyme-substrate complex
B. Binds at a site other than the active site
, C. Competes with the substrate for the active site
D. Is irreversible
C. Competes with the substrate for the active site
Competitive inhibitors resemble the substrate and block binding at
the active site.
6. Which of the following is a characteristic of enzymes?
A. Used up during the reaction
B. Irreversibly altered
C. Highly specific for their substrates
D. Only found in eukaryotic cells
C. Highly specific for their substrates
Enzymes bind specific substrates and catalyze specific reactions.
7. Which enzyme model suggests conformational changes upon
substrate binding?
A. Lock and key
B. Induced fit
C. Rigid body
D. Ping-pong
B. Induced fit
The induced fit model proposes that the enzyme changes shape to
accommodate the substrate.
8. The Michaelis constant (Km) represents:
A. The maximum reaction velocity
, B. The substrate concentration at half Vmax
C. The enzyme turnover number
D. The energy barrier
B. The substrate concentration at half Vmax
Km is a measure of substrate affinity; a lower Km indicates higher
affinity.
9. Enzymes that require a cofactor but lack one are called:
A. Apoenzymes
B. Holoenzymes
C. Cofactors
D. Proenzymes
A. Apoenzymes
An apoenzyme is the inactive protein component of an enzyme that
requires a cofactor to become active.
10. A zymogen is:
A. A coenzyme
B. An inactive enzyme precursor
C. An allosteric inhibitor
D. A feedback activator
B. An inactive enzyme precursor
Zymogens require activation (e.g., by cleavage) to become functional
enzymes.
Questions And Correct Answers
(Verified Answers) Plus Rationales 2025
Q&A | Instant Download PDF
1. Which of the following is not a function of enzymes?
A. Lower activation energy
B. Alter the equilibrium constant
C. Increase reaction rate
D. Provide specificity for substrates
B. Alter the equilibrium constant
Enzymes speed up reactions but do not change the overall
thermodynamics, such as the equilibrium constant.
2. The region of the enzyme where substrate binds is called the:
A. Regulatory site
B. Allosteric site
C. Active site
, D. Inhibitory site
C. Active site
The active site is the specific region where the substrate binds and
the reaction occurs.
3. A coenzyme is:
A. A non-protein organic molecule essential for enzyme activity
B. A metal ion that binds permanently
C. A protein helper of enzymes
D. The same as a zymogen
A. A non-protein organic molecule essential for enzyme activity
Coenzymes are small organic molecules that assist enzymes in
catalysis.
4. Which vitamin is a precursor for NAD⁺/NADP⁺?
A. Vitamin C
B. Niacin
C. Riboflavin
D. Biotin
B. Niacin
Niacin is converted into NAD⁺ and NADP⁺, which function as electron
carriers.
5. In competitive inhibition, the inhibitor:
A. Binds to the enzyme-substrate complex
B. Binds at a site other than the active site
, C. Competes with the substrate for the active site
D. Is irreversible
C. Competes with the substrate for the active site
Competitive inhibitors resemble the substrate and block binding at
the active site.
6. Which of the following is a characteristic of enzymes?
A. Used up during the reaction
B. Irreversibly altered
C. Highly specific for their substrates
D. Only found in eukaryotic cells
C. Highly specific for their substrates
Enzymes bind specific substrates and catalyze specific reactions.
7. Which enzyme model suggests conformational changes upon
substrate binding?
A. Lock and key
B. Induced fit
C. Rigid body
D. Ping-pong
B. Induced fit
The induced fit model proposes that the enzyme changes shape to
accommodate the substrate.
8. The Michaelis constant (Km) represents:
A. The maximum reaction velocity
, B. The substrate concentration at half Vmax
C. The enzyme turnover number
D. The energy barrier
B. The substrate concentration at half Vmax
Km is a measure of substrate affinity; a lower Km indicates higher
affinity.
9. Enzymes that require a cofactor but lack one are called:
A. Apoenzymes
B. Holoenzymes
C. Cofactors
D. Proenzymes
A. Apoenzymes
An apoenzyme is the inactive protein component of an enzyme that
requires a cofactor to become active.
10. A zymogen is:
A. A coenzyme
B. An inactive enzyme precursor
C. An allosteric inhibitor
D. A feedback activator
B. An inactive enzyme precursor
Zymogens require activation (e.g., by cleavage) to become functional
enzymes.
