C785 Biochemistry Module 6: Metabolism Exam Prep 2026 |WGU
1. Which process describes the breakdown of complex molecules into simpler
ones, usually releasing energy?
A. Anabolism
B. Photosynthesis
C. Catabolism
D. Isomerization
Answer: C
Rationale: Catabolism refers to metabolic pathways that break down molecules into
smaller units to release energy.
2. Where does glycolysis occur in a eukaryotic cell?
A. Mitochondrial matrix
B. Nucleus
C. Cytosol
D. Endoplasmic reticulum
Answer: C
Rationale: Glycolysis takes place in the cytoplasm (cytosol) of the cell.
,3. What is the net gain of ATP molecules from one molecule of glucose during
glycolysis?
A. 2 ATP
B. 1 ATP
C. 4 ATP
D. 36 ATP
Answer: A
Rationale: Glycolysis consumes 2 ATP and produces 4 ATP, resulting in a net gain of 2 ATP
per glucose.
4. Which enzyme is the primary rate-limiting step of glycolysis?
A. Hexokinase
B. Pyruvate kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
Answer: C
Rationale: PFK-1 is the key regulatory and rate-limiting enzyme in glycolysis, controlled
by ATP and citrate levels.
5. Under anaerobic conditions, pyruvate is converted to what in human muscle
cells?
A. Acetyl-CoA
B. Ethanol
C. Oxaloacetate
D. Lactate
Answer: D
Rationale: In the absence of oxygen, pyruvate is reduced to lactate to regenerate NAD+ for
glycolysis to continue.
, 6. What is the role of the Pyruvate Dehydrogenase Complex (PDC)?
A. Convert pyruvate to Acetyl-CoA
B. Convert pyruvate to glucose
C. Convert lactate to pyruvate
D. Convert Acetyl-CoA to CO2
Answer: A
Rationale: The PDC links glycolysis to the Citric Acid Cycle by converting pyruvate into
Acetyl-CoA in the mitochondria.
7. How many molecules of NADH are produced during one turn of the Citric Acid
Cycle?
A. 1
B. 3
C. 2
D. 4
Answer: B
Rationale: One turn of the Citric Acid Cycle produces 3 NADH, 1 FADH2, and 1 GTP/ATP.
8. Which molecule condenses with Acetyl-CoA to begin the Citric Acid Cycle?
A. Oxaloacetate
B. Malate
C. Citrate
D. Succinate
Answer: A
Rationale: Acetyl-CoA (2C) combines with oxaloacetate (4C) to form citrate (6C).
1. Which process describes the breakdown of complex molecules into simpler
ones, usually releasing energy?
A. Anabolism
B. Photosynthesis
C. Catabolism
D. Isomerization
Answer: C
Rationale: Catabolism refers to metabolic pathways that break down molecules into
smaller units to release energy.
2. Where does glycolysis occur in a eukaryotic cell?
A. Mitochondrial matrix
B. Nucleus
C. Cytosol
D. Endoplasmic reticulum
Answer: C
Rationale: Glycolysis takes place in the cytoplasm (cytosol) of the cell.
,3. What is the net gain of ATP molecules from one molecule of glucose during
glycolysis?
A. 2 ATP
B. 1 ATP
C. 4 ATP
D. 36 ATP
Answer: A
Rationale: Glycolysis consumes 2 ATP and produces 4 ATP, resulting in a net gain of 2 ATP
per glucose.
4. Which enzyme is the primary rate-limiting step of glycolysis?
A. Hexokinase
B. Pyruvate kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
Answer: C
Rationale: PFK-1 is the key regulatory and rate-limiting enzyme in glycolysis, controlled
by ATP and citrate levels.
5. Under anaerobic conditions, pyruvate is converted to what in human muscle
cells?
A. Acetyl-CoA
B. Ethanol
C. Oxaloacetate
D. Lactate
Answer: D
Rationale: In the absence of oxygen, pyruvate is reduced to lactate to regenerate NAD+ for
glycolysis to continue.
, 6. What is the role of the Pyruvate Dehydrogenase Complex (PDC)?
A. Convert pyruvate to Acetyl-CoA
B. Convert pyruvate to glucose
C. Convert lactate to pyruvate
D. Convert Acetyl-CoA to CO2
Answer: A
Rationale: The PDC links glycolysis to the Citric Acid Cycle by converting pyruvate into
Acetyl-CoA in the mitochondria.
7. How many molecules of NADH are produced during one turn of the Citric Acid
Cycle?
A. 1
B. 3
C. 2
D. 4
Answer: B
Rationale: One turn of the Citric Acid Cycle produces 3 NADH, 1 FADH2, and 1 GTP/ATP.
8. Which molecule condenses with Acetyl-CoA to begin the Citric Acid Cycle?
A. Oxaloacetate
B. Malate
C. Citrate
D. Succinate
Answer: A
Rationale: Acetyl-CoA (2C) combines with oxaloacetate (4C) to form citrate (6C).
