Vitamin 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 · Vitamin metabolism

Sample item

Which biochemical process is impaired when folate is deficient?

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

The answer and the reasoning

C. Thymidylate synthesis for DNA replication

Folate transfers one-carbon groups needed for thymidylate and purine synthesis, so deficiency impairs DNA replication and produces megaloblastic change in rapidly dividing cells such as marrow precursors.

Option by option

  • A. Oxygen binding by haemoglobin

    Haemoglobin oxygen binding is not a folate-dependent reaction.

  • B. Beta-oxidation of fatty acids

    Fatty-acid beta-oxidation depends mainly on mitochondrial enzymes and cofactors.

  • C. Thymidylate synthesis for DNA replication (correct)

    Correct: folate is essential for thymidylate production and DNA synthesis.

  • D. Renal filtration of creatinine

    Creatinine filtration depends on renal function, not folate transfer.

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, Thymidylate synthesis for DNA replication. Folate transfers one-carbon groups needed for thymidylate and purine synthesis, so deficiency impairs DNA replication and produces megaloblastic change in rapidly dividing cells such as marrow precursors.

Why is "Oxygen binding by haemoglobin" not the answer?

Haemoglobin oxygen binding is not a folate-dependent reaction.

Why is "Beta-oxidation of fatty acids" not the answer?

Fatty-acid beta-oxidation depends mainly on mitochondrial enzymes and cofactors.

Why is "Renal filtration of creatinine" not the answer?

Creatinine filtration depends on renal function, not folate transfer.

What concept does this question test?

It tests Vitamin metabolism in Biochemistry. The correct option holds because: Correct: folate is essential for thymidylate production and DNA synthesis.

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 Vitamin 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.