250+ TOP MCQs on Biosynthesis of Fatty Acids and Eicosanoids and Answers

Biochemistry Multiple Choice Questions on “Biosynthesis of Fatty Acids and Eicosanoids”.

1. Conversion of acetyl co-A to malonyl co-A requires which of the following?
A. NADPH
B. H₂O
C. Folic acid
D. Biotin
Answer: D
Clarification: Transcarboxylase transfers activated CO₂ from biotin to acetyl co-A producing malonyl co-A.

2. The prosthetic group of acyl carrier protein is ___________
A. 4’-phosphopantetheine
B. 3’-phosphopantetheine
C. 2’-phosphopantetheine
D. 1’-phosphopantetheine
Answer: A
Clarification: Acyl protein carrier (ACP) is a small protein containing the prosthetic group 4’-phosphopantetheine.

3. Which of the following carries acyl groups in thio-ester linkage?
A. Acyl carrier protein
B. Acetyl co-A ACP transacetylase
C. Enoyl-ACP reductase
D. Malonyl co-A ACP transferase
Answer: A
Clarification: Acetyl co-A ACP transacetylase transfers acyl group from co-A to cys residue of KS.
β-ketoacyl ACP synthase condenses acyl and malonyl groups.
Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP.

4. Which of the following transfers acyl group from co-A to cys residue of KS?
A. Acyl carrier protein
B. Acetyl co-A ACP transacetylase
C. Enoyl-ACP reductase
D. Malonyl co-A ACP transferase
Answer: B
Clarification: β-ketoacyl ACP synthase condenses acyl and malonyl groups.
Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP.
Acyl carrier protein carries acyl groups in thio-ester linkage.

5. Which of the following condenses acyl and malonyl groups?
A. Acyl carrier protein
B. Acetyl co-A ACP transacetylase
C. β-ketoacyl ACP synthase
D. Malonyl co-A ACP transferase
Answer: C
Clarification: Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP.
Acyl carrier protein carries acyl groups in thio-ester linkage.
Acetyl co-A ACP transacetylase transfers acyl group from co-A to cys residue of KS.

6. Which of the following transfers malonyl group from co-A to ACP?
A. Acyl carrier protein
B. Acetyl co-A ACP transacetylase
C. Enoyl-ACP reductase
D. Malonyl co-A ACP transferase
Answer: D
Clarification: Acyl carrier protein carries acyl groups in thio-ester linkage.
Acetyl co-A ACP transacetylase transfers acyl group from co-A to cys residue of KS.
β-ketoacyl ACP synthase condenses acyl and malonyl groups.

7. Which of the following reduces β-keto group to β-hydroxyl group?
A. β-ketoacyl ACP reductase
B. β-hydroxyacyl ACP dehydratase
C. Enoyl ACP reductase
D. Malonyl co-A ACP transferase
Answer: A
Clarification: β-hydroxyacyl ACP dehydratase removes H₂O from β-hydroxyl ACP, creating double bond.
Enoyl ACP reductase reduces double bond, forming saturated acyl ACP.
Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP.

8. Which of the following removes H₂O from β-hydroxyl ACP, creating double bond?
A. β-ketoacyl ACP reductase
B. β-hydroxyacyl ACP dehydratase
C. Enoyl ACP reductase
D. Malonyl co-A ACP transferase
Answer: B
Clarification: Enoyl ACP reductase reduces double bond, forming saturated acyl ACP.
Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP.
β-Ketoacyl ACP reductase reduces β-keto group to β-hydroxyl group.

9. Which of the following reduces double bond, forming saturated acyl ACP?
A. β-ketoacyl ACP reductase
B. β-hydroxyacyl ACP dehydratase
C. Enoyl ACP reductase
D. Malonyl co-A ACP transferase
Answer: C
Clarification: Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP.
β-Ketoacyl ACP reductase reduces β-keto group to β-hydroxyl group.
β-Hydroxyacyl ACP dehydratase removes H₂O from β-hydroxyl ACP, creating a double bond.

10. Which of the following converts PGH₂ to thromboxane A₂?
A. Enoyl-ACP reductase
B. β-ketoacyl ACP reductase
C. Cyclooxygenase
D. Thromboxane synthase
Answer: D
Clarification: Thromboxane synthase present in blood platelets converts PGH₂ to thromboxane A₂.

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