Cholesterol metabolism: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Biochemistry · Cholesterol metabolism

Sample item

Which enzyme is the rate-limiting target of statins in cholesterol synthesis?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. HMG-CoA reductase

HMG-CoA reductase converts HMG-CoA to mevalonate, the rate-limiting step of cholesterol synthesis. Statins inhibit this enzyme and increase hepatic LDL-receptor expression.

Option by option

  • A. Acetyl-CoA carboxylase

    Acetyl-CoA carboxylase is rate limiting for fatty-acid synthesis.

  • B. Lipoprotein lipase

    Lipoprotein lipase hydrolyzes circulating triglycerides.

  • C. HMG-CoA lyase

    HMG-CoA lyase functions in ketogenesis.

  • D. HMG-CoA reductase (correct)

    Correct. Statins act at the mevalonate-forming step.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Biochemistry questions

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is D, HMG-CoA reductase. HMG-CoA reductase converts HMG-CoA to mevalonate, the rate-limiting step of cholesterol synthesis.

Why is "Acetyl-CoA carboxylase" not the answer?

Acetyl-CoA carboxylase is rate limiting for fatty-acid synthesis.

Why is "Lipoprotein lipase" not the answer?

Lipoprotein lipase hydrolyzes circulating triglycerides.

Why is "HMG-CoA lyase" not the answer?

HMG-CoA lyase functions in ketogenesis.

What concept does this question test?

It tests Cholesterol metabolism in Biochemistry. Statins inhibit this enzyme and increase hepatic LDL-receptor expression.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Cholesterol metabolism?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.