Vitamins: thiamine: 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: thiamine

Sample item

Which enzyme requires thiamine pyrophosphate as a cofactor?

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

The answer and the reasoning

C. Pyruvate dehydrogenase

Thiamine pyrophosphate is required for oxidative decarboxylation reactions, including pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, branched-chain ketoacid dehydrogenase, and transketolase.

Option by option

  • A. Carbonic anhydrase

    Carbonic anhydrase requires zinc.

  • B. HMG-CoA reductase

    HMG-CoA reductase is regulated in cholesterol synthesis.

  • C. Pyruvate dehydrogenase (correct)

    Correct. Pyruvate dehydrogenase requires thiamine-derived TPP.

  • D. Succinate dehydrogenase

    Succinate dehydrogenase uses FAD.

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, Pyruvate dehydrogenase. Thiamine pyrophosphate is required for oxidative decarboxylation reactions, including pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, branched-chain ketoacid dehydrogenase, and transketolase.

Why is "Carbonic anhydrase" not the answer?

Carbonic anhydrase requires zinc.

Why is "HMG-CoA reductase" not the answer?

HMG-CoA reductase is regulated in cholesterol synthesis.

Why is "Succinate dehydrogenase" not the answer?

Succinate dehydrogenase uses FAD.

What concept does this question test?

It tests Vitamins: thiamine in Biochemistry. The correct option holds because: Correct. Pyruvate dehydrogenase requires thiamine-derived TPP.

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: thiamine?

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.