Lipid metabolism: hepatic lipase: 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: hepatic lipase

Sample item

An endothelium-bound lipase on the sinusoidal surface of hepatocytes hydrolyses triglycerides and phospholipids in IDL and in HDL2. Which enzyme is this?

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

The answer and the reasoning

A. Hepatic lipase

Hepatic lipase converts IDL to LDL and converts triglyceride-rich HDL2 to the smaller HDL3 by hydrolysing triglycerides and phospholipids. Lipoprotein lipase works on chylomicrons and VLDL in capillaries of muscle and adipose tissue.

Option by option

  • A. Hepatic lipase (correct)

    Correct. Hepatic lipase acts on IDL and HDL2 at the hepatic sinusoids.

  • B. Lipoprotein lipase

    Lipoprotein lipase hydrolyses triglycerides of chylomicrons and VLDL in muscle and adipose capillaries and needs apoC-II.

  • C. Lecithin-cholesterol acyltransferase

    Lecithin-cholesterol acyltransferase esterifies cholesterol on HDL and does not hydrolyse triglycerides.

  • D. Hormone-sensitive lipase

    Hormone-sensitive lipase is intracellular and hydrolyses stored triglyceride in adipocytes, not lipoprotein lipids.

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.

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Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is A, Hepatic lipase. Hepatic lipase converts IDL to LDL and converts triglyceride-rich HDL2 to the smaller HDL3 by hydrolysing triglycerides and phospholipids.

Why is "Lipoprotein lipase" not the answer?

Lipoprotein lipase hydrolyses triglycerides of chylomicrons and VLDL in muscle and adipose capillaries and needs apoC-II.

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

Lecithin-cholesterol acyltransferase esterifies cholesterol on HDL and does not hydrolyse triglycerides.

Why is "Hormone-sensitive lipase" not the answer?

Hormone-sensitive lipase is intracellular and hydrolyses stored triglyceride in adipocytes, not lipoprotein lipids.

What concept does this question test?

It tests Lipid metabolism: hepatic lipase in Biochemistry. Lipoprotein lipase works on chylomicrons and VLDL in capillaries of muscle and adipose tissue.

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: hepatic lipase?

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.