Biochemistry Carbohydrate Metabolism (Glycolysis, Gluconeogenesis)
Practice Pack 2026 |WGU
1. What is the net gain of ATP molecules per molecule of glucose during
anaerobic glycolysis?
A. 4 ATP
B. 2 ATP
C. 36 ATP
D. 0 ATP
Answer: B
Rationale: While 4 ATP are produced in the payoff phase, 2 ATP are consumed in the
investment phase, resulting in a net gain of 2 ATP.
2. Which enzyme catalyzes the rate-limiting and most regulated step of
glycolysis?
A. Hexokinase
B. Pyruvate Kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
Answer: C
Rationale: PFK-1 catalyzes the conversion of Fructose-6-phosphate to Fructose-1,6-
bisphosphate, which is the primary control point of glycolysis.
,3. In gluconeogenesis, which enzyme is used to bypass the irreversible step
catalyzed by Hexokinase in glycolysis?
A. Phosphoenolpyruvate carboxykinase
B. Fructose-1,6-bisphosphatase
C. Pyruvate Carboxylase
D. Glucose-6-phosphatase
Answer: D
Rationale: Glucose-6-phosphatase removes the phosphate group from glucose-6-
phosphate to produce free glucose, bypassing the hexokinase step.
4. Which molecule acts as an allosteric activator of Pyruvate Carboxylase in
gluconeogenesis?
A. Acetyl-CoA
B. ADP
C. Insulin
D. Fructose-2,6-bisphosphate
Answer: A
Rationale: High levels of Acetyl-CoA signal that the cell has enough energy and metabolic
intermediates, stimulating the first step of gluconeogenesis.
5. Where does the final step of gluconeogenesis primarily occur within the cell?
A. Cytosol
B. Mitochondrial Matrix
C. Endoplasmic Reticulum (ER)
D. Lysosome
Answer: C
Rationale: Glucose-6-phosphatase is located in the lumen of the ER; glucose-6-phosphate
must be transported into the ER to be converted to glucose.
, 6. Which enzyme in glycolysis catalyzes a substrate-level phosphorylation to
produce ATP?
A. Glyceraldehyde-3-phosphate dehydrogenase
B. Phosphoglycerate kinase
C. Enolase
D. Hexokinase
Answer: B
Rationale: Phosphoglycerate kinase transfers a phosphate from 1,3-bisphosphoglycerate
to ADP to form ATP.
7. What is the primary role of the Cori Cycle?
A. To produce glucose from fatty acids
B. To convert glucose into glycogen in the liver
C. To transport lactate from muscles to the liver for conversion to glucose
D. To facilitate the breakdown of amino acids for energy
Answer: C
Rationale: The Cori Cycle involves the conversion of lactate produced by anaerobic
glycolysis in muscles back into glucose in the liver.
8. Which hormonal signal promotes glycolysis in the liver by increasing the
concentration of Fructose-2,6-bisphosphate?
A. Insulin
B. Epinephrine
C. Glucagon
D. Cortisol
Answer: A
Rationale: Insulin leads to the activation of PFK-2, which increases F-2,6-BP levels, thereby
stimulating PFK-1 and glycolysis.
Practice Pack 2026 |WGU
1. What is the net gain of ATP molecules per molecule of glucose during
anaerobic glycolysis?
A. 4 ATP
B. 2 ATP
C. 36 ATP
D. 0 ATP
Answer: B
Rationale: While 4 ATP are produced in the payoff phase, 2 ATP are consumed in the
investment phase, resulting in a net gain of 2 ATP.
2. Which enzyme catalyzes the rate-limiting and most regulated step of
glycolysis?
A. Hexokinase
B. Pyruvate Kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
Answer: C
Rationale: PFK-1 catalyzes the conversion of Fructose-6-phosphate to Fructose-1,6-
bisphosphate, which is the primary control point of glycolysis.
,3. In gluconeogenesis, which enzyme is used to bypass the irreversible step
catalyzed by Hexokinase in glycolysis?
A. Phosphoenolpyruvate carboxykinase
B. Fructose-1,6-bisphosphatase
C. Pyruvate Carboxylase
D. Glucose-6-phosphatase
Answer: D
Rationale: Glucose-6-phosphatase removes the phosphate group from glucose-6-
phosphate to produce free glucose, bypassing the hexokinase step.
4. Which molecule acts as an allosteric activator of Pyruvate Carboxylase in
gluconeogenesis?
A. Acetyl-CoA
B. ADP
C. Insulin
D. Fructose-2,6-bisphosphate
Answer: A
Rationale: High levels of Acetyl-CoA signal that the cell has enough energy and metabolic
intermediates, stimulating the first step of gluconeogenesis.
5. Where does the final step of gluconeogenesis primarily occur within the cell?
A. Cytosol
B. Mitochondrial Matrix
C. Endoplasmic Reticulum (ER)
D. Lysosome
Answer: C
Rationale: Glucose-6-phosphatase is located in the lumen of the ER; glucose-6-phosphate
must be transported into the ER to be converted to glucose.
, 6. Which enzyme in glycolysis catalyzes a substrate-level phosphorylation to
produce ATP?
A. Glyceraldehyde-3-phosphate dehydrogenase
B. Phosphoglycerate kinase
C. Enolase
D. Hexokinase
Answer: B
Rationale: Phosphoglycerate kinase transfers a phosphate from 1,3-bisphosphoglycerate
to ADP to form ATP.
7. What is the primary role of the Cori Cycle?
A. To produce glucose from fatty acids
B. To convert glucose into glycogen in the liver
C. To transport lactate from muscles to the liver for conversion to glucose
D. To facilitate the breakdown of amino acids for energy
Answer: C
Rationale: The Cori Cycle involves the conversion of lactate produced by anaerobic
glycolysis in muscles back into glucose in the liver.
8. Which hormonal signal promotes glycolysis in the liver by increasing the
concentration of Fructose-2,6-bisphosphate?
A. Insulin
B. Epinephrine
C. Glucagon
D. Cortisol
Answer: A
Rationale: Insulin leads to the activation of PFK-2, which increases F-2,6-BP levels, thereby
stimulating PFK-1 and glycolysis.
