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

Which transport mechanism moves long-chain fatty acyl groups into mitochondria for beta-oxidation?

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

The answer and the reasoning

D. Carnitine shuttle

Long-chain fatty acyl groups require the carnitine shuttle to cross the inner mitochondrial membrane before beta-oxidation can proceed in the matrix.

Option by option

  • A. Malate-aspartate shuttle

    The malate-aspartate shuttle transfers reducing equivalents, not fatty acyl groups.

  • B. Ubiquitin-proteasome pathway

    The ubiquitin-proteasome pathway degrades tagged proteins.

  • C. Sodium-potassium pump

    The sodium-potassium pump maintains membrane ion gradients.

  • D. Carnitine shuttle (correct)

    Correct: carnitine transfers long-chain acyl groups across the inner membrane.

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 D, Carnitine shuttle. Long-chain fatty acyl groups require the carnitine shuttle to cross the inner mitochondrial membrane before beta-oxidation can proceed in the matrix.

Why is "Malate-aspartate shuttle" not the answer?

The malate-aspartate shuttle transfers reducing equivalents, not fatty acyl groups.

Why is "Ubiquitin-proteasome pathway" not the answer?

The ubiquitin-proteasome pathway degrades tagged proteins.

Why is "Sodium-potassium pump" not the answer?

The sodium-potassium pump maintains membrane ion gradients.

What concept does this question test?

It tests Lipid metabolism in Biochemistry. The correct option holds because: Correct: carnitine transfers long-chain acyl groups across the inner membrane.

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.