EXSS 256: COMPREHENSIVE PRACTICE EXAM
QUESTIONS WITH COMPLETE SOLUTIONS
Table of Content
Section Domain Approx. Page
Questions Reference
1 Carbohydrate Metabolism, 50 Page 2
Glycolysis, and Gluconeogenesis
2 Lipid Metabolism, Lipolysis, and 50 Page 10
Beta-Oxidation
3 Cellular Respiration, Krebs 50 Page 18
Cycle, and ATP
4 Integrated Metabolism, 50 Page 26
Starvation, and Exercise
Section 1: Carbohydrate Metabolism, Glycolysis, and Gluconeogenesis
(Questions 1-50)
1. Which process describes the synthesis of glucose from non-
carbohydrate sources like amino acids?
A. Glycolysis
B. Lipolysis
C. Gluconeogenesis
D. Beta oxidation
Correct Answer: C
Rationale: Gluconeogenesis is the metabolic pathway that results in the
,generation of glucose from certain non-carbohydrate carbon substrates,
such as amino acids, lactate, and glycerol.
2. During prolonged exercise, which hormone primarily stimulates
gluconeogenesis to maintain blood glucose levels?
A. Insulin
B. Glucagon
C. Cortisol
D. Aldosterone
Correct Answer: B
Rationale: Glucagon is the primary hormone responsible for stimulating
gluconeogenesis in the liver during fasting or prolonged exercise to
maintain euglycemia.
3. Where does glycolysis occur within the cell?
A. Mitochondria
B. Nucleus
C. Cytoplasm
D. Endoplasmic reticulum
Correct Answer: C
Rationale: Glycolysis is an anaerobic process that takes place in the
cytoplasm of the cell, not requiring oxygen or mitochondria.
4. What is the net ATP yield from one molecule of glucose during
glycolysis?
A. 1 ATP
B. 2 ATP
C. 4 ATP
D. 36 ATP
Correct Answer: B
,Rationale: Glycolysis produces 4 ATP molecules but consumes 2 ATP in
the preparatory phase, resulting in a net yield of 2 ATP per glucose
molecule.
5. Which substrate is NOT a precursor for gluconeogenesis?
A. Alanine
B. Glycerol
C. Lactate
D. Acetyl-CoA
Correct Answer: D
Rationale: Acetyl-CoA cannot be used as a precursor for
gluconeogenesis in humans because the pyruvate dehydrogenase
reaction is irreversible.
6. In the absence of oxygen, pyruvate is converted to which molecule
to regenerate NAD+?
A. Acetyl-CoA
B. Lactic acid
C. Ethanol
D. Citrate
Correct Answer: B
Rationale: In the absence of oxygen, pyruvate is reduced to lactic acid
by lactate dehydrogenase, which oxidizes NADH to NAD+ to allow
glycolysis to continue.
7. Which enzyme catalyzes the rate-limiting step of glycolysis?
A. Hexokinase
B. Phosphofructokinase-1
C. Pyruvate kinase
D. Lactate dehydrogenase
, Correct Answer: B
Rationale: Phosphofructokinase-1 (PFK-1) is the rate-limiting enzyme of
glycolysis, heavily regulated by ATP, AMP, and citrate levels.
8. The conversion of lactate back to glucose primarily occurs in which
organ?
A. Muscle
B. Liver
C. Brain
D. Kidneys
Correct Answer: B
Rationale: The Cori cycle involves the transport of lactate from muscle
to the liver, where it is converted back to glucose via gluconeogenesis.
9. What is the primary fate of glucose-6-phosphate in the liver during
fasting?
A. Glycolysis
B. Glycogenesis
C. Gluconeogenesis
D. Pentose phosphate pathway
Correct Answer: C
Rationale: During fasting, the liver produces glucose-6-phosphatase to
convert glucose-6-phosphate to free glucose for release into the blood.
10. Which of the following is an anaerobic process?
A. Krebs cycle
B. Beta oxidation
C. Glycolysis
D. Oxidative phosphorylation
Correct Answer: C
QUESTIONS WITH COMPLETE SOLUTIONS
Table of Content
Section Domain Approx. Page
Questions Reference
1 Carbohydrate Metabolism, 50 Page 2
Glycolysis, and Gluconeogenesis
2 Lipid Metabolism, Lipolysis, and 50 Page 10
Beta-Oxidation
3 Cellular Respiration, Krebs 50 Page 18
Cycle, and ATP
4 Integrated Metabolism, 50 Page 26
Starvation, and Exercise
Section 1: Carbohydrate Metabolism, Glycolysis, and Gluconeogenesis
(Questions 1-50)
1. Which process describes the synthesis of glucose from non-
carbohydrate sources like amino acids?
A. Glycolysis
B. Lipolysis
C. Gluconeogenesis
D. Beta oxidation
Correct Answer: C
Rationale: Gluconeogenesis is the metabolic pathway that results in the
,generation of glucose from certain non-carbohydrate carbon substrates,
such as amino acids, lactate, and glycerol.
2. During prolonged exercise, which hormone primarily stimulates
gluconeogenesis to maintain blood glucose levels?
A. Insulin
B. Glucagon
C. Cortisol
D. Aldosterone
Correct Answer: B
Rationale: Glucagon is the primary hormone responsible for stimulating
gluconeogenesis in the liver during fasting or prolonged exercise to
maintain euglycemia.
3. Where does glycolysis occur within the cell?
A. Mitochondria
B. Nucleus
C. Cytoplasm
D. Endoplasmic reticulum
Correct Answer: C
Rationale: Glycolysis is an anaerobic process that takes place in the
cytoplasm of the cell, not requiring oxygen or mitochondria.
4. What is the net ATP yield from one molecule of glucose during
glycolysis?
A. 1 ATP
B. 2 ATP
C. 4 ATP
D. 36 ATP
Correct Answer: B
,Rationale: Glycolysis produces 4 ATP molecules but consumes 2 ATP in
the preparatory phase, resulting in a net yield of 2 ATP per glucose
molecule.
5. Which substrate is NOT a precursor for gluconeogenesis?
A. Alanine
B. Glycerol
C. Lactate
D. Acetyl-CoA
Correct Answer: D
Rationale: Acetyl-CoA cannot be used as a precursor for
gluconeogenesis in humans because the pyruvate dehydrogenase
reaction is irreversible.
6. In the absence of oxygen, pyruvate is converted to which molecule
to regenerate NAD+?
A. Acetyl-CoA
B. Lactic acid
C. Ethanol
D. Citrate
Correct Answer: B
Rationale: In the absence of oxygen, pyruvate is reduced to lactic acid
by lactate dehydrogenase, which oxidizes NADH to NAD+ to allow
glycolysis to continue.
7. Which enzyme catalyzes the rate-limiting step of glycolysis?
A. Hexokinase
B. Phosphofructokinase-1
C. Pyruvate kinase
D. Lactate dehydrogenase
, Correct Answer: B
Rationale: Phosphofructokinase-1 (PFK-1) is the rate-limiting enzyme of
glycolysis, heavily regulated by ATP, AMP, and citrate levels.
8. The conversion of lactate back to glucose primarily occurs in which
organ?
A. Muscle
B. Liver
C. Brain
D. Kidneys
Correct Answer: B
Rationale: The Cori cycle involves the transport of lactate from muscle
to the liver, where it is converted back to glucose via gluconeogenesis.
9. What is the primary fate of glucose-6-phosphate in the liver during
fasting?
A. Glycolysis
B. Glycogenesis
C. Gluconeogenesis
D. Pentose phosphate pathway
Correct Answer: C
Rationale: During fasting, the liver produces glucose-6-phosphatase to
convert glucose-6-phosphate to free glucose for release into the blood.
10. Which of the following is an anaerobic process?
A. Krebs cycle
B. Beta oxidation
C. Glycolysis
D. Oxidative phosphorylation
Correct Answer: C
