Carbohydrate 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.

Try it

Biochemistry · Carbohydrate metabolism

Sample item

Which cofactor is required by the pyruvate dehydrogenase complex and is derived from vitamin B1?

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

The answer and the reasoning

B. Thiamine pyrophosphate

Thiamine pyrophosphate, derived from vitamin B1, is required for oxidative decarboxylation of pyruvate by pyruvate dehydrogenase and for several other key metabolic enzyme complexes.

Option by option

  • A. Biotin

    Biotin carries carbon dioxide in carboxylation reactions.

  • B. Thiamine pyrophosphate (correct)

    Correct: thiamine pyrophosphate is the B1-derived pyruvate dehydrogenase cofactor.

  • C. Cobalamin

    Cobalamin is vitamin B12 and is used in methylmalonyl-CoA metabolism.

  • D. Folate

    Folate transfers one-carbon units in nucleotide and amino-acid pathways.

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 B, Thiamine pyrophosphate. Thiamine pyrophosphate, derived from vitamin B1, is required for oxidative decarboxylation of pyruvate by pyruvate dehydrogenase and for several other key metabolic enzyme complexes.

Why is "Biotin" not the answer?

Biotin carries carbon dioxide in carboxylation reactions.

Why is "Cobalamin" not the answer?

Cobalamin is vitamin B12 and is used in methylmalonyl-CoA metabolism.

Why is "Folate" not the answer?

Folate transfers one-carbon units in nucleotide and amino-acid pathways.

What concept does this question test?

It tests Carbohydrate metabolism in Biochemistry. The correct option holds because: Correct: thiamine pyrophosphate is the B1-derived pyruvate dehydrogenase cofactor.

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 Carbohydrate 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.