Lipid 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.

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Biochemistry · Lipid metabolism

Sample item

A rare loss-of-function mutation in a plasma protein produces very high HDL cholesterol, because exchange of core lipids between HDL and apoB-containing lipoproteins is reduced. Which protein is affected?

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

The answer and the reasoning

A. Cholesteryl ester transfer protein

CETP moves cholesteryl esters from HDL to VLDL and LDL in exchange for triglyceride. Its deficiency leaves cholesteryl esters in HDL and raises the HDL level. CETP inhibitors were studied for this reason.

Option by option

  • A. Cholesteryl ester transfer protein (correct)

    Correct. CETP mediates the lipid exchange between HDL and apoB lipoproteins.

  • B. Lecithin-cholesterol acyltransferase

    LCAT esterifies cholesterol on HDL and its loss lowers HDL cholesterol.

  • C. Hepatic lipase

    Hepatic lipase remodels HDL and IDL but does not exchange core lipids.

  • D. Lipoprotein lipase

    Lipoprotein lipase hydrolyses triglyceride in chylomicrons and VLDL.

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 A, Cholesteryl ester transfer protein. CETP moves cholesteryl esters from HDL to VLDL and LDL in exchange for triglyceride.

Why is "Lecithin-cholesterol acyltransferase" not the answer?

LCAT esterifies cholesterol on HDL and its loss lowers HDL cholesterol.

Why is "Hepatic lipase" not the answer?

Hepatic lipase remodels HDL and IDL but does not exchange core lipids.

Why is "Lipoprotein lipase" not the answer?

Lipoprotein lipase hydrolyses triglyceride in chylomicrons and VLDL.

What concept does this question test?

It tests Lipid metabolism in Biochemistry. Its deficiency leaves cholesteryl esters in HDL and raises the HDL level. CETP inhibitors were studied for this reason.

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 Lipid 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.