BioChem 210 Module 7 Exam ACTUAL EXAM
2026/2027 | Complete Exam-Style Q&A | Verified
Q&A | Pass Guaranteed - A+ Graded
Table of Contents
Section 1: Metabolic Pathways & Energy Production (Questions 1–10) ...... 2
Section 2: Lipid Metabolism (Questions 11–20) ...... 2
Section 3: Amino Acid & Protein Metabolism (Questions 21–30) ...... 2
Section 4: Nucleotide & Nucleic Acid Metabolism (Questions 31–40) ...... 2
Section 5: Integration & Regulation of Metabolism (Questions 41–50) ...... 2
Section 1: Metabolic Pathways & Energy Production
Q1: The net ATP yield from one molecule of glucose undergoing complete aerobic oxidation to CO₂ and
H₂O is approximately:
A. 2 ATP
B. 10 ATP
C. 30-32 ATP. [CORRECT]
D. 100 ATP
Correct Answer: C
Rationale: Complete aerobic oxidation of glucose yields approximately 30-32 ATP. Glycolysis produces 2
ATP (net) and 2 NADH. Pyruvate dehydrogenase converts pyruvate to acetyl-CoA, generating 2 NADH.
The TCA cycle produces 6 NADH, 2 FADH₂, and 2 GTP per glucose. Oxidative phosphorylation generates
approximately 2.5 ATP per NADH and 1.5 ATP per FADH₂, totaling 30-32 ATP depending on shuttle
mechanisms used for cytosolic NADH.
Q2: The enzyme phosphofructokinase-1 (PFK-1) is the primary regulatory enzyme of glycolysis. In the
presence of high ATP and citrate, PFK-1 activity is:
A. Activated
B. Inhibited. [CORRECT]
C. Unchanged
D. Doubled
,Correct Answer: B
Rationale: PFK-1 is the rate-limiting enzyme of glycolysis and is allosterically inhibited by high
concentrations of ATP and citrate. High ATP indicates sufficient cellular energy, while citrate indicates
active TCA cycle and ample biosynthetic precursors. This inhibition prevents unnecessary glucose
breakdown when energy is abundant, conserving glucose for other metabolic needs.
Q3: A patient with a deficiency in pyruvate dehydrogenase complex would most likely present with:
A. Hypoglycemia
B. Lactic acidosis. [CORRECT]
C. Hyperkalemia
D. Hypocalcemia
Correct Answer: B
Rationale: Pyruvate dehydrogenase complex converts pyruvate to acetyl-CoA for entry into the TCA
cycle. When this enzyme is deficient, pyruvate cannot enter the TCA cycle and is instead shunted to
lactate via lactate dehydrogenase. This accumulation of lactate produces lactic acidosis, which is the
characteristic laboratory finding in pyruvate dehydrogenase deficiency. Patients may also present with
neurological symptoms due to energy failure.
Q4: The TCA cycle produces per turn (per acetyl-CoA):
A. 1 NADH, 1 FADH₂, 1 ATP
B. 3 NADH, 1 FADH₂, 1 GTP. *CORRECT+
C. 2 NADH, 2 FADH₂, 2 ATP
D. 6 NADH, 2 FADH₂, 2 GTP
Correct Answer: B
Rationale: Each turn of the TCA cycle oxidizes one acetyl-CoA molecule, producing 3 NADH (from
isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, and malate dehydrogenase), 1 FADH₂ (from
succinate dehydrogenase), and 1 GTP (from succinyl-CoA synthetase via substrate-level
phosphorylation). These reduced coenzymes then enter the electron transport chain for ATP synthesis.
Q5: In the electron transport chain, Complex I (NADH dehydrogenase) transfers electrons from NADH to:
A. Oxygen directly
B. Ubiquinone (Coenzyme Q). [CORRECT]
C. Cytochrome c
D. ATP synthase
, Correct Answer: B
Rationale: Complex I (NADH dehydrogenase) oxidizes NADH to NAD⁺, transferring electrons through
flavin mononucleotide (FMN) and iron-sulfur clusters to ubiquinone (Coenzyme Q), reducing it to
ubiquinol. This electron transfer pumps four protons from the mitochondrial matrix to the
intermembrane space, contributing to the proton gradient that drives ATP synthesis.
Q6: The final electron acceptor in the electron transport chain is:
A. NAD⁺
B. FAD
C. Oxygen. [CORRECT]
D. Carbon dioxide
Correct Answer: C
Rationale: Complex IV (cytochrome c oxidase) transfers electrons from cytochrome c to molecular
oxygen, which serves as the final electron acceptor in the electron transport chain. Oxygen is reduced to
water in this reaction: O₂ + 4e⁻ + 4H⁺ → 2H₂O. This makes oxygen essential for aerobic respiration and
explains why oxygen deprivation rapidly impairs ATP production.
Q7: ATP synthase (Complex V) synthesizes ATP using the energy from:
A. Direct oxidation of NADH
B. The proton gradient (proton-motive force) across the inner mitochondrial membrane. [CORRECT]
C. Direct phosphorylation of ADP by oxygen
D. Heat energy from the mitochondrial matrix
Correct Answer: B
Rationale: ATP synthase is a rotary enzyme that uses the electrochemical proton gradient (proton-
motive force) generated by Complexes I, III, and IV to synthesize ATP from ADP and inorganic
phosphate. Protons flow through the F₀ subunit from the intermembrane space to the matrix, driving
rotation of the F₁ subunit, which catalyzes ATP synthesis. This process is called chemiosmosis.
Q8: During glycogenolysis, the enzyme that cleaves α-1,4-glycosidic bonds to release glucose-1-
phosphate is:
A. Glycogen synthase
B. Glycogen phosphorylase. [CORRECT]
C. Branching enzyme
D. Debranching enzyme
2026/2027 | Complete Exam-Style Q&A | Verified
Q&A | Pass Guaranteed - A+ Graded
Table of Contents
Section 1: Metabolic Pathways & Energy Production (Questions 1–10) ...... 2
Section 2: Lipid Metabolism (Questions 11–20) ...... 2
Section 3: Amino Acid & Protein Metabolism (Questions 21–30) ...... 2
Section 4: Nucleotide & Nucleic Acid Metabolism (Questions 31–40) ...... 2
Section 5: Integration & Regulation of Metabolism (Questions 41–50) ...... 2
Section 1: Metabolic Pathways & Energy Production
Q1: The net ATP yield from one molecule of glucose undergoing complete aerobic oxidation to CO₂ and
H₂O is approximately:
A. 2 ATP
B. 10 ATP
C. 30-32 ATP. [CORRECT]
D. 100 ATP
Correct Answer: C
Rationale: Complete aerobic oxidation of glucose yields approximately 30-32 ATP. Glycolysis produces 2
ATP (net) and 2 NADH. Pyruvate dehydrogenase converts pyruvate to acetyl-CoA, generating 2 NADH.
The TCA cycle produces 6 NADH, 2 FADH₂, and 2 GTP per glucose. Oxidative phosphorylation generates
approximately 2.5 ATP per NADH and 1.5 ATP per FADH₂, totaling 30-32 ATP depending on shuttle
mechanisms used for cytosolic NADH.
Q2: The enzyme phosphofructokinase-1 (PFK-1) is the primary regulatory enzyme of glycolysis. In the
presence of high ATP and citrate, PFK-1 activity is:
A. Activated
B. Inhibited. [CORRECT]
C. Unchanged
D. Doubled
,Correct Answer: B
Rationale: PFK-1 is the rate-limiting enzyme of glycolysis and is allosterically inhibited by high
concentrations of ATP and citrate. High ATP indicates sufficient cellular energy, while citrate indicates
active TCA cycle and ample biosynthetic precursors. This inhibition prevents unnecessary glucose
breakdown when energy is abundant, conserving glucose for other metabolic needs.
Q3: A patient with a deficiency in pyruvate dehydrogenase complex would most likely present with:
A. Hypoglycemia
B. Lactic acidosis. [CORRECT]
C. Hyperkalemia
D. Hypocalcemia
Correct Answer: B
Rationale: Pyruvate dehydrogenase complex converts pyruvate to acetyl-CoA for entry into the TCA
cycle. When this enzyme is deficient, pyruvate cannot enter the TCA cycle and is instead shunted to
lactate via lactate dehydrogenase. This accumulation of lactate produces lactic acidosis, which is the
characteristic laboratory finding in pyruvate dehydrogenase deficiency. Patients may also present with
neurological symptoms due to energy failure.
Q4: The TCA cycle produces per turn (per acetyl-CoA):
A. 1 NADH, 1 FADH₂, 1 ATP
B. 3 NADH, 1 FADH₂, 1 GTP. *CORRECT+
C. 2 NADH, 2 FADH₂, 2 ATP
D. 6 NADH, 2 FADH₂, 2 GTP
Correct Answer: B
Rationale: Each turn of the TCA cycle oxidizes one acetyl-CoA molecule, producing 3 NADH (from
isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, and malate dehydrogenase), 1 FADH₂ (from
succinate dehydrogenase), and 1 GTP (from succinyl-CoA synthetase via substrate-level
phosphorylation). These reduced coenzymes then enter the electron transport chain for ATP synthesis.
Q5: In the electron transport chain, Complex I (NADH dehydrogenase) transfers electrons from NADH to:
A. Oxygen directly
B. Ubiquinone (Coenzyme Q). [CORRECT]
C. Cytochrome c
D. ATP synthase
, Correct Answer: B
Rationale: Complex I (NADH dehydrogenase) oxidizes NADH to NAD⁺, transferring electrons through
flavin mononucleotide (FMN) and iron-sulfur clusters to ubiquinone (Coenzyme Q), reducing it to
ubiquinol. This electron transfer pumps four protons from the mitochondrial matrix to the
intermembrane space, contributing to the proton gradient that drives ATP synthesis.
Q6: The final electron acceptor in the electron transport chain is:
A. NAD⁺
B. FAD
C. Oxygen. [CORRECT]
D. Carbon dioxide
Correct Answer: C
Rationale: Complex IV (cytochrome c oxidase) transfers electrons from cytochrome c to molecular
oxygen, which serves as the final electron acceptor in the electron transport chain. Oxygen is reduced to
water in this reaction: O₂ + 4e⁻ + 4H⁺ → 2H₂O. This makes oxygen essential for aerobic respiration and
explains why oxygen deprivation rapidly impairs ATP production.
Q7: ATP synthase (Complex V) synthesizes ATP using the energy from:
A. Direct oxidation of NADH
B. The proton gradient (proton-motive force) across the inner mitochondrial membrane. [CORRECT]
C. Direct phosphorylation of ADP by oxygen
D. Heat energy from the mitochondrial matrix
Correct Answer: B
Rationale: ATP synthase is a rotary enzyme that uses the electrochemical proton gradient (proton-
motive force) generated by Complexes I, III, and IV to synthesize ATP from ADP and inorganic
phosphate. Protons flow through the F₀ subunit from the intermembrane space to the matrix, driving
rotation of the F₁ subunit, which catalyzes ATP synthesis. This process is called chemiosmosis.
Q8: During glycogenolysis, the enzyme that cleaves α-1,4-glycosidic bonds to release glucose-1-
phosphate is:
A. Glycogen synthase
B. Glycogen phosphorylase. [CORRECT]
C. Branching enzyme
D. Debranching enzyme
