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 fasting plasma sample looks milky. After standing overnight, a cream layer forms on top, and agarose gel electrophoresis shows a dense band at the origin. Which lipoprotein stays at the origin?

AChylomicronsBHDLCLDLDVLDL

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

The answer and the reasoning

A. Chylomicrons

Chylomicrons are too large and carry too little protein to move in the electric field, so they remain at the origin. HDL migrates as alpha, VLDL as pre-beta and LDL as beta lipoprotein. Fasting chylomicronaemia suggests lipoprotein lipase or apoC-II deficiency.

Option by option

A. Chylomicrons (correct)
Correct. Chylomicrons are large and protein-poor, so they stay at the point of application.
B. HDL
HDL migrates fastest, in the alpha position.
C. LDL
LDL migrates in the beta position.
D. VLDL
VLDL migrates in the pre-beta position.

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.

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is A, Chylomicrons. Chylomicrons are too large and carry too little protein to move in the electric field, so they remain at the origin.

Why is "HDL" not the answer?

HDL migrates fastest, in the alpha position.

Why is "LDL" not the answer?

LDL migrates in the beta position.

Why is "VLDL" not the answer?

VLDL migrates in the pre-beta position.

What concept does this question test?

It tests Lipid metabolism in Biochemistry. HDL migrates as alpha, VLDL as pre-beta and LDL as beta lipoprotein. Fasting chylomicronaemia suggests lipoprotein lipase or apoC-II deficiency.

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.