Purines: 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 · Purines

Sample item

Which enzyme converts hypoxanthine to xanthine?

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

The answer and the reasoning

C. Xanthine oxidase

This item reviews Purines; Xanthine oxidase is the best answer because it directly fits the mechanism or morphology described.

Option by option

  • A. Thymidylate synthase

    Thymidylate synthase is plausible but is not the best fit here.

  • B. ADA

    ADA is not supported by the stated finding.

  • C. Xanthine oxidase (correct)

    Correct. Xanthine oxidase is supported by the defining finding.

  • D. HGPRT

    HGPRT does not match the key mechanism or pattern.

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.

More Biochemistry questions

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is C, Xanthine oxidase. This item reviews Purines; Xanthine oxidase is the best answer because it directly fits the mechanism or morphology described.

Why is "Thymidylate synthase" not the answer?

Thymidylate synthase is plausible but is not the best fit here.

Why is "ADA" not the answer?

ADA is not supported by the stated finding.

Why is "HGPRT" not the answer?

HGPRT does not match the key mechanism or pattern.

What concept does this question test?

It tests Purines in Biochemistry. The correct option holds because: Correct. Xanthine oxidase is supported by the defining finding.

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 Purines?

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.