Principles of Biochemistry Exam III
Actual Questions and Answers 2026
CDP-diglyceride is not involved in the biosynthesis of:
A) phosphatidylcholine.
B) phosphatidylethanolamine
C) phosphatidylglycerol.
D) phosphatidylserine.
E) sphingomyelin. -
correct answer ✅E) sphingomyelin
Which of the following is not required in the
synthesis of fatty acids?
A) Acetyl-CoA
B) Biotin
C) HCO; (CO,)
D) MalonvI-CoA
E) NADH -
correct answer ✅E) NADH
we use NADPH, not NADH
If malonyl-CoA is synthesized from 14CO, and unlabeled
acetyl-CoA, and the labeled malonate is then used for fatty
,Principles of Biochemistry Exam III
Actual Questions and Answers 2026
acid synthesis, the final product (fatty acid) will have
radioactive carbon in:
A) every C.
B) every even-numbered C-atom.
C) every odd-numbered C-atom.
D) no part of the molecule.
E) only the omega-carbon atom (farthest carbon from C-1). -
correct answer ✅D) no part of the molecule
CO2 is added and then removed, not incorporated
Which of the following is not an intermediate in the
synthesis of lanosterol from acetvl-CoA?
A) Isopenteny1 pyrophosphate
B) Malonyl-CoA
C) Mevalonate
D) Squalene
E) Hydroxy-ß-methylglutary1-CoA (HMG-CoA) -
correct answer ✅B) Malonyl-CoA
Which of the following is not a step in the uptake of
,Principles of Biochemistry Exam III
Actual Questions and Answers 2026
cholesterol from the bloodstream into cells?
A) LDL containing ApoB-100 is recognized by the LDL
receptor.
B) LDL bound to the LDL receptor leads to endocytosis of
the complex.
C) The cholesteryl esters in the LDL are hydrolyzed to
release free cholesterol.
D) The internalized receptor is degraded.
E) The ApoB-100 protein is degraded. -
correct answer ✅D) The internalized receptor is degraded.
Which of the following does not contribute to lowering
the risk of atherosclerosis?
A) Statin drugs
B) HDL
C) Reverse cholesterol transport
D) ApoA-I
E) Foam cells -
correct answer ✅E) Foam cells
, Principles of Biochemistry Exam III
Actual Questions and Answers 2026
Which of the following statements about the fixation of
atmospheric nitrogen (N,) into NH, by living cells is false?
A) It involves the transfer of eight electrons per mol of No.
B) It occurs in certain microorganisms, but not in humans
C) It requires a source of electrons, normally ferredoxin.
D) It requires one ATP per mol of N, fixed.
E) It requires two key protein components, each containing iron. -
correct answer ✅D) It requires one ATP per mol of N, fixed.
16 ATP/N2 fixed
Which of the following enzymes is not involved in the
assimilation of inorganic nitrogen into an organic molecule?
A) Dinitrogenase reductase
B) Nitrate reductase
C) Nitrite reductase
D) Nitrile reductase
E) Dinitrogenase -
correct answer ✅D) Nitrile reductase
Which of the following is not true about
Actual Questions and Answers 2026
CDP-diglyceride is not involved in the biosynthesis of:
A) phosphatidylcholine.
B) phosphatidylethanolamine
C) phosphatidylglycerol.
D) phosphatidylserine.
E) sphingomyelin. -
correct answer ✅E) sphingomyelin
Which of the following is not required in the
synthesis of fatty acids?
A) Acetyl-CoA
B) Biotin
C) HCO; (CO,)
D) MalonvI-CoA
E) NADH -
correct answer ✅E) NADH
we use NADPH, not NADH
If malonyl-CoA is synthesized from 14CO, and unlabeled
acetyl-CoA, and the labeled malonate is then used for fatty
,Principles of Biochemistry Exam III
Actual Questions and Answers 2026
acid synthesis, the final product (fatty acid) will have
radioactive carbon in:
A) every C.
B) every even-numbered C-atom.
C) every odd-numbered C-atom.
D) no part of the molecule.
E) only the omega-carbon atom (farthest carbon from C-1). -
correct answer ✅D) no part of the molecule
CO2 is added and then removed, not incorporated
Which of the following is not an intermediate in the
synthesis of lanosterol from acetvl-CoA?
A) Isopenteny1 pyrophosphate
B) Malonyl-CoA
C) Mevalonate
D) Squalene
E) Hydroxy-ß-methylglutary1-CoA (HMG-CoA) -
correct answer ✅B) Malonyl-CoA
Which of the following is not a step in the uptake of
,Principles of Biochemistry Exam III
Actual Questions and Answers 2026
cholesterol from the bloodstream into cells?
A) LDL containing ApoB-100 is recognized by the LDL
receptor.
B) LDL bound to the LDL receptor leads to endocytosis of
the complex.
C) The cholesteryl esters in the LDL are hydrolyzed to
release free cholesterol.
D) The internalized receptor is degraded.
E) The ApoB-100 protein is degraded. -
correct answer ✅D) The internalized receptor is degraded.
Which of the following does not contribute to lowering
the risk of atherosclerosis?
A) Statin drugs
B) HDL
C) Reverse cholesterol transport
D) ApoA-I
E) Foam cells -
correct answer ✅E) Foam cells
, Principles of Biochemistry Exam III
Actual Questions and Answers 2026
Which of the following statements about the fixation of
atmospheric nitrogen (N,) into NH, by living cells is false?
A) It involves the transfer of eight electrons per mol of No.
B) It occurs in certain microorganisms, but not in humans
C) It requires a source of electrons, normally ferredoxin.
D) It requires one ATP per mol of N, fixed.
E) It requires two key protein components, each containing iron. -
correct answer ✅D) It requires one ATP per mol of N, fixed.
16 ATP/N2 fixed
Which of the following enzymes is not involved in the
assimilation of inorganic nitrogen into an organic molecule?
A) Dinitrogenase reductase
B) Nitrate reductase
C) Nitrite reductase
D) Nitrile reductase
E) Dinitrogenase -
correct answer ✅D) Nitrile reductase
Which of the following is not true about
