CHEM 219 MODULE 7: LIPID
METABOLISM AND REGULATION
QUESTIONS WITH CORRECT ANSWERS
2026/2027 UPDATE. JUST RELEASED
1. Which enzyme catalyzes the rate-limiting step of fatty acid synthesis, converting acetyl-CoA
to malonyl-CoA?
A. Acetyl-CoA carboxylase
B. Fatty acid synthase
C. Pyruvate carboxylase
D. Malic enzyme
Answer: A
Conceptual Explanation: Acetyl-CoA carboxylase (ACC) is the regulatory enzyme that
produces malonyl-CoA, which also inhibits fatty acid oxidation via CPT-1.
2. How many rounds of beta-oxidation are required to fully oxidize a 16-carbon palmitic acid
molecule?
A. 8
B. 16
C. 9
,D. 7
Answer: D
Conceptual Explanation: A fatty acid with N carbons requires (N/2)-1 rounds of beta-
oxidation. For 16 carbons, that is (16/2)-1 = 7 rounds.
3. Which molecule is responsible for transporting long-chain fatty acids across the inner
mitochondrial membrane?
A. Citrate
B. Carnitine
C. Acyl-carrier protein
D. Albumin
Answer: B
Conceptual Explanation: Carnitine is required to shuttle long-chain fatty acids into the
mitochondrial matrix through the carnitine-acyltransferase system.
4. What is the net ATP yield from the complete oxidation of one molecule of palmitate (16:0)?
A. 106 ATP
B. 129 ATP
C. 108 ATP
D. 98 ATP
, Answer: A
Conceptual Explanation: Palmitate yields 8 Acetyl-CoA, 7 FADH2, and 7 NADH.
Subtracting the 2 ATP equivalents for activation results in a net of 106 ATP.
5. Which of the following ketone bodies is produced by the spontaneous decarboxylation of
acetoacetate?
A. Beta-hydroxybutyrate
B. Oxaloacetate
C. Pyruvate
D. Acetone
Answer: D
Conceptual Explanation: Acetone is formed by the non-enzymatic spontaneous
decarboxylation of acetoacetate during high levels of ketogenesis.
6. The enzyme HMG-CoA reductase is the rate-limiting step for the synthesis of which
molecule?
A. Fatty acids
B. Ketone bodies
C. Phospholipids
D. Cholesterol
Answer: D
METABOLISM AND REGULATION
QUESTIONS WITH CORRECT ANSWERS
2026/2027 UPDATE. JUST RELEASED
1. Which enzyme catalyzes the rate-limiting step of fatty acid synthesis, converting acetyl-CoA
to malonyl-CoA?
A. Acetyl-CoA carboxylase
B. Fatty acid synthase
C. Pyruvate carboxylase
D. Malic enzyme
Answer: A
Conceptual Explanation: Acetyl-CoA carboxylase (ACC) is the regulatory enzyme that
produces malonyl-CoA, which also inhibits fatty acid oxidation via CPT-1.
2. How many rounds of beta-oxidation are required to fully oxidize a 16-carbon palmitic acid
molecule?
A. 8
B. 16
C. 9
,D. 7
Answer: D
Conceptual Explanation: A fatty acid with N carbons requires (N/2)-1 rounds of beta-
oxidation. For 16 carbons, that is (16/2)-1 = 7 rounds.
3. Which molecule is responsible for transporting long-chain fatty acids across the inner
mitochondrial membrane?
A. Citrate
B. Carnitine
C. Acyl-carrier protein
D. Albumin
Answer: B
Conceptual Explanation: Carnitine is required to shuttle long-chain fatty acids into the
mitochondrial matrix through the carnitine-acyltransferase system.
4. What is the net ATP yield from the complete oxidation of one molecule of palmitate (16:0)?
A. 106 ATP
B. 129 ATP
C. 108 ATP
D. 98 ATP
, Answer: A
Conceptual Explanation: Palmitate yields 8 Acetyl-CoA, 7 FADH2, and 7 NADH.
Subtracting the 2 ATP equivalents for activation results in a net of 106 ATP.
5. Which of the following ketone bodies is produced by the spontaneous decarboxylation of
acetoacetate?
A. Beta-hydroxybutyrate
B. Oxaloacetate
C. Pyruvate
D. Acetone
Answer: D
Conceptual Explanation: Acetone is formed by the non-enzymatic spontaneous
decarboxylation of acetoacetate during high levels of ketogenesis.
6. The enzyme HMG-CoA reductase is the rate-limiting step for the synthesis of which
molecule?
A. Fatty acids
B. Ketone bodies
C. Phospholipids
D. Cholesterol
Answer: D
