CHEM 210 Biochemistry Module 3 Practice
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2025
Q&A | Instant Download PDF
1. Which of the following best describes the function of an enzyme?
A. Increases the activation energy
B. Alters the equilibrium of the reaction
C. Lowers the activation energy
D. Acts as a product of the reaction
Enzymes lower the activation energy needed to start a reaction,
thereby speeding it up.
2. A noncompetitive inhibitor affects an enzyme by:
A. Binding to the active site
B. Binding to an allosteric site
C. Increasing substrate concentration
D. Changing the enzyme’s primary structure
, Noncompetitive inhibitors bind to an allosteric site, altering enzyme
shape and function.
3. The Michaelis constant (Km) reflects:
A. The maximum velocity of the enzyme
B. The substrate concentration at half Vmax
C. The number of active sites
D. The product concentration
Km is the substrate concentration at which an enzyme reaches half of
its maximum velocity (Vmax).
4. Which graph shape represents Michaelis-Menten kinetics?
A. Sigmoidal
B. Hyperbolic
C. Linear
D. Parabolic
Michaelis-Menten kinetics show a hyperbolic relationship between
velocity and substrate concentration.
5. Allosteric enzymes often exhibit:
A. Sigmoidal kinetics
B. Hyperbolic kinetics
C. Linear kinetics
D. Constant kinetics
Allosteric enzymes usually show sigmoidal curves due to cooperative
substrate binding.
,6. A Lineweaver-Burk plot is used to:
A. Directly measure enzyme concentration
B. Determine Km and Vmax
C. Visualize primary structure
D. Separate isozymes
Lineweaver-Burk plots linearize Michaelis-Menten data to extract Km
and Vmax values.
7. Which type of inhibitor increases Km but does not affect Vmax?
A. Competitive
B. Noncompetitive
C. Uncompetitive
D. Irreversible
Competitive inhibitors compete with substrate for the active site,
increasing Km.
8. Which coenzyme is commonly involved in redox reactions?
A. Coenzyme A
B. Biotin
C. NAD+
D. Thiamine pyrophosphate
NAD+ is a key electron carrier in oxidation-reduction reactions.
9. Enzymes catalyze reactions by:
A. Increasing the ΔG of the reaction
B. Altering the net energy change
, C. Making reactions non-spontaneous
D. Lowering the transition state energy
Enzymes lower the energy required to reach the transition state,
speeding up reactions.
10. Which amino acid is most likely to participate in acid-base
catalysis?
A. Leucine
B. Glycine
C. Histidine
D. Valine
Histidine's imidazole group can donate or accept protons, making it
ideal for acid-base catalysis.
11. Which of the following is a zymogen?
A. Trypsin
B. Amylase
C. Pepsinogen
D. Hexokinase
Pepsinogen is an inactive enzyme precursor (zymogen) activated in
acidic conditions.
12. What is the role of feedback inhibition?
A. Enhances enzyme activity
B. Prevents overaccumulation of the end product
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2025
Q&A | Instant Download PDF
1. Which of the following best describes the function of an enzyme?
A. Increases the activation energy
B. Alters the equilibrium of the reaction
C. Lowers the activation energy
D. Acts as a product of the reaction
Enzymes lower the activation energy needed to start a reaction,
thereby speeding it up.
2. A noncompetitive inhibitor affects an enzyme by:
A. Binding to the active site
B. Binding to an allosteric site
C. Increasing substrate concentration
D. Changing the enzyme’s primary structure
, Noncompetitive inhibitors bind to an allosteric site, altering enzyme
shape and function.
3. The Michaelis constant (Km) reflects:
A. The maximum velocity of the enzyme
B. The substrate concentration at half Vmax
C. The number of active sites
D. The product concentration
Km is the substrate concentration at which an enzyme reaches half of
its maximum velocity (Vmax).
4. Which graph shape represents Michaelis-Menten kinetics?
A. Sigmoidal
B. Hyperbolic
C. Linear
D. Parabolic
Michaelis-Menten kinetics show a hyperbolic relationship between
velocity and substrate concentration.
5. Allosteric enzymes often exhibit:
A. Sigmoidal kinetics
B. Hyperbolic kinetics
C. Linear kinetics
D. Constant kinetics
Allosteric enzymes usually show sigmoidal curves due to cooperative
substrate binding.
,6. A Lineweaver-Burk plot is used to:
A. Directly measure enzyme concentration
B. Determine Km and Vmax
C. Visualize primary structure
D. Separate isozymes
Lineweaver-Burk plots linearize Michaelis-Menten data to extract Km
and Vmax values.
7. Which type of inhibitor increases Km but does not affect Vmax?
A. Competitive
B. Noncompetitive
C. Uncompetitive
D. Irreversible
Competitive inhibitors compete with substrate for the active site,
increasing Km.
8. Which coenzyme is commonly involved in redox reactions?
A. Coenzyme A
B. Biotin
C. NAD+
D. Thiamine pyrophosphate
NAD+ is a key electron carrier in oxidation-reduction reactions.
9. Enzymes catalyze reactions by:
A. Increasing the ΔG of the reaction
B. Altering the net energy change
, C. Making reactions non-spontaneous
D. Lowering the transition state energy
Enzymes lower the energy required to reach the transition state,
speeding up reactions.
10. Which amino acid is most likely to participate in acid-base
catalysis?
A. Leucine
B. Glycine
C. Histidine
D. Valine
Histidine's imidazole group can donate or accept protons, making it
ideal for acid-base catalysis.
11. Which of the following is a zymogen?
A. Trypsin
B. Amylase
C. Pepsinogen
D. Hexokinase
Pepsinogen is an inactive enzyme precursor (zymogen) activated in
acidic conditions.
12. What is the role of feedback inhibition?
A. Enhances enzyme activity
B. Prevents overaccumulation of the end product
