C785 Biochemistry Week 6 Study Guide Assessment 2026 |WGU
1. Which of the following is the net yield of ATP molecules produced per
molecule of glucose during glycolysis?
A. 4 ATP
B. 36 ATP
C. 2 ATP
D. 32 ATP
Answer: C
Rationale: Glycolysis uses 2 ATP and produces 4 ATP, resulting in a net gain of 2 ATP per
glucose molecule.
2. Where in the cell does the process of glycolysis take place?
A. Mitochondrial matrix
B. Inner mitochondrial membrane
C. Cytosol
D. Nucleus
Answer: C
Rationale: Glycolysis occurs in the cytosol of the cell, where the necessary enzymes are
located.
3. Which enzyme is responsible for the ‘committed step’ of glycolysis?
A. Hexokinase
B. Pyruvate Kinase
C. Glucokinase
D. Phosphofructokinase-1
Answer: D
,Rationale: Phosphofructokinase-1 (PFK-1) catalyzes the conversion of fructose-6-
phosphate to fructose-1,6-bisphosphate, which is the key regulatory and committed step.
4. Under anaerobic conditions, what is pyruvate converted into in human
muscle cells?
A. Ethanol
B. Lactate
C. Acetyl-CoA
D. Oxaloacetate
Answer: B
Rationale: In the absence of oxygen, pyruvate is reduced to lactate to regenerate NAD+ for
glycolysis to continue.
5. Which molecule enters the Citric Acid Cycle by combining with oxaloacetate?
A. Pyruvate
B. Citrate
C. Acetyl-CoA
D. Malate
Answer: C
Rationale: Acetyl-CoA combines with the four-carbon oxaloacetate to form the six-carbon
citrate, initiating the cycle.
6. How many NADH molecules are produced during one single turn of the Citric
Acid Cycle?
A. 1 NADH
B. 2 NADH
C. 3 NADH
D. 4 NADH
Answer: C
, Rationale: One turn of the Citric Acid Cycle produces three NADH, one FADH2, and one
GTP (or ATP).
7. What is the primary function of the Electron Transport Chain?
A. To produce CO2
B. To create a proton gradient across the inner mitochondrial membrane
C. To break down glucose into pyruvate
D. To synthesize glucose from non-carbohydrate sources
Answer: B
Rationale: The ETC uses high-energy electrons to pump protons into the intermembrane
space, creating a gradient used by ATP synthase.
8. Which complex in the Electron Transport Chain is also known as Succinate
Dehydrogenase?
A. Complex I
B. Complex IV
C. Complex III
D. Complex II
Answer: D
Rationale: Complex II (Succinate Dehydrogenase) is the only membrane-bound enzyme of
the Citric Acid Cycle and transfers electrons from FADH2 to the ETC.
9. What is the final electron acceptor in the mitochondrial electron transport
chain?
A. Water
B. Oxygen
C. Carbon Dioxide
D. NAD+
Answer: B
1. Which of the following is the net yield of ATP molecules produced per
molecule of glucose during glycolysis?
A. 4 ATP
B. 36 ATP
C. 2 ATP
D. 32 ATP
Answer: C
Rationale: Glycolysis uses 2 ATP and produces 4 ATP, resulting in a net gain of 2 ATP per
glucose molecule.
2. Where in the cell does the process of glycolysis take place?
A. Mitochondrial matrix
B. Inner mitochondrial membrane
C. Cytosol
D. Nucleus
Answer: C
Rationale: Glycolysis occurs in the cytosol of the cell, where the necessary enzymes are
located.
3. Which enzyme is responsible for the ‘committed step’ of glycolysis?
A. Hexokinase
B. Pyruvate Kinase
C. Glucokinase
D. Phosphofructokinase-1
Answer: D
,Rationale: Phosphofructokinase-1 (PFK-1) catalyzes the conversion of fructose-6-
phosphate to fructose-1,6-bisphosphate, which is the key regulatory and committed step.
4. Under anaerobic conditions, what is pyruvate converted into in human
muscle cells?
A. Ethanol
B. Lactate
C. Acetyl-CoA
D. Oxaloacetate
Answer: B
Rationale: In the absence of oxygen, pyruvate is reduced to lactate to regenerate NAD+ for
glycolysis to continue.
5. Which molecule enters the Citric Acid Cycle by combining with oxaloacetate?
A. Pyruvate
B. Citrate
C. Acetyl-CoA
D. Malate
Answer: C
Rationale: Acetyl-CoA combines with the four-carbon oxaloacetate to form the six-carbon
citrate, initiating the cycle.
6. How many NADH molecules are produced during one single turn of the Citric
Acid Cycle?
A. 1 NADH
B. 2 NADH
C. 3 NADH
D. 4 NADH
Answer: C
, Rationale: One turn of the Citric Acid Cycle produces three NADH, one FADH2, and one
GTP (or ATP).
7. What is the primary function of the Electron Transport Chain?
A. To produce CO2
B. To create a proton gradient across the inner mitochondrial membrane
C. To break down glucose into pyruvate
D. To synthesize glucose from non-carbohydrate sources
Answer: B
Rationale: The ETC uses high-energy electrons to pump protons into the intermembrane
space, creating a gradient used by ATP synthase.
8. Which complex in the Electron Transport Chain is also known as Succinate
Dehydrogenase?
A. Complex I
B. Complex IV
C. Complex III
D. Complex II
Answer: D
Rationale: Complex II (Succinate Dehydrogenase) is the only membrane-bound enzyme of
the Citric Acid Cycle and transfers electrons from FADH2 to the ETC.
9. What is the final electron acceptor in the mitochondrial electron transport
chain?
A. Water
B. Oxygen
C. Carbon Dioxide
D. NAD+
Answer: B
