Question

Match List I with List II

Choose the correct answer from the options given below:

• A. A-I, B-V, C-III, D-IV
• B. A-V, B-I, C-II, D-IV
• C. A-V, B-I, C-III, D-IV
• D. A-I, B-V, C-II, D-IV

Hint:

Carnitine = "Car" that transports fat into the "Garage" (Mitochondria).
$B_{12}$ = The "Odd-ball" cofactor (for odd carbon chains).
Pantothenic Acid $\rightarrow$ Coenzyme A $\rightarrow$ ACP.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This is a matching question involving the roles of various enzymes and cofactors in lipid metabolism (synthesis, transport, and oxidation).

Step 2: Detailed Explanation:

• Coenzyme $B_{12$ (A):} Oxidation of odd-chain fatty acids produces Propionyl-CoA, which is eventually converted to Succinyl-CoA. The final enzyme in this pathway, Methylmalonyl-CoA mutase, requires Vitamin $B_{12}$ (Cobalamin). Therefore, A matches with I.

• 2,4-Dienoyl CoA reductase (B): Normal $\beta$-oxidation works on saturated bonds. Polyunsaturated fatty acids produce intermediates with double bonds in the wrong positions or configurations. This enzyme, along with an isomerase, is needed to resolve these bonds. Therefore, B matches with V.

• Pantothenic acid (C): Vitamin $B_5$ is the precursor for Coenzyme A and the 4'-phosphopantetheine group. The latter is the essential prosthetic group attached to the Acyl Carrier Protein (ACP) used in fatty acid synthesis. Therefore, C matches with III.

• Carnitine (D): Long-chain fatty acids cannot cross the inner mitochondrial membrane on their own. They are converted to acyl-carnitine to be ferried across by the carnitine shuttle. Therefore, D matches with IV.

• Note on II: Acetyl-CoA carboxylase requires Biotin, not the ones listed here.

Step 3: Final Answer:
The correct matching sequence according to metabolic functions is A-I, B-V, C-III, D-IV.