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

Raw egg-white consumption can cause deficiency of which vitamin because avidin binds it tightly?

APyridoxineBBiotinCNiacinDFolate

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

The answer and the reasoning

B. Biotin

Avidin in raw egg white binds biotin. Biotin serves as a cofactor for carboxylases, so deficiency may cause dermatitis, alopecia and metabolic acidosis.

Option by option

A. Pyridoxine
Pyridoxine is involved in aminotransferases and heme synthesis.
B. Biotin (correct)
Correct. Avidin sequesters biotin.
C. Niacin
Niacin deficiency causes dermatitis, diarrhoea and dementia.
D. Folate
Folate is needed for one-carbon transfer reactions.

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 B, Biotin. Avidin in raw egg white binds biotin.

Why is "Pyridoxine" not the answer?

Pyridoxine is involved in aminotransferases and heme synthesis.

Why is "Niacin" not the answer?

Niacin deficiency causes dermatitis, diarrhoea and dementia.

Why is "Folate" not the answer?

Folate is needed for one-carbon transfer reactions.

What concept does this question test?

It tests Vitamins: biotin in Biochemistry. Biotin serves as a cofactor for carboxylases, so deficiency may cause dermatitis, alopecia and metabolic acidosis.

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.