UKMLA PLAB AMC USMLE Prometric MCQ

Correct Answer: A

Explanation:
The correct answer is a) hydroxy-3-methylglutaryl coenzyme A reductase Cholesterol synthesis begins with the synthesis of acetoacetyl CoA from two acetyl CoA molecules. A third acetyl CoA molecule is added by the enzyme HMG CoA synthase to form 3 Hydroxy-3-MethylGlutaryl-CoA (HMG CoA). HMG CoA is reduced by the action of HMG CoA reductase to mevalonic acid using NADPH as the hydrogen donor. The end product molecule, cholesterol, acts as a feedback inhibitor of HMG CoA reductase to regulate the intra- and intercellular levels of cholesterol. Synthetic lipid lowering agents may mimick the inhibitory effects of cholesterol