Vitamins: biotin: 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 · Vitamins: biotin

Sample item

Biotin acts as a cofactor for which type of biochemical reaction?

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

The answer and the reasoning

C. Carboxylation reactions

Biotin is a cofactor for carboxylases, including pyruvate carboxylase, acetyl-CoA carboxylase, and propionyl-CoA carboxylase. Raw egg-white avidin can bind biotin and cause deficiency in extreme settings.

Option by option

  • A. Gamma-carboxylation of clotting factors

    Gamma-carboxylation of coagulation factors requires vitamin K.

  • B. Transamination reactions only

    Transaminases require pyridoxine.

  • C. Carboxylation reactions (correct)

    Correct. Biotin carries carbon dioxide in carboxylation reactions.

  • D. Hydroxylation of proline

    Proline hydroxylation requires vitamin C.

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 C, Carboxylation reactions. Biotin is a cofactor for carboxylases, including pyruvate carboxylase, acetyl-CoA carboxylase, and propionyl-CoA carboxylase.

Why is "Gamma-carboxylation of clotting factors" not the answer?

Gamma-carboxylation of coagulation factors requires vitamin K.

Why is "Transamination reactions only" not the answer?

Transaminases require pyridoxine.

Why is "Hydroxylation of proline" not the answer?

Proline hydroxylation requires vitamin C.

What concept does this question test?

It tests Vitamins: biotin in Biochemistry. Raw egg-white avidin can bind biotin and cause deficiency in extreme settings.

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 Vitamins: biotin?

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.