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.

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Biochemistry · Carbohydrate metabolism

Sample item

What enzyme converts glucose-6-phosphate to fructose-6-phosphate in glycolysis?

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

The answer and the reasoning

A. Phosphoglucose isomerase

Phosphoglucose isomerase rearranges glucose-6-phosphate into fructose-6-phosphate, preparing the molecule for the committed phosphorylation step of glycolysis.

Option by option

  • A. Phosphoglucose isomerase (correct)

    Correct: this enzyme isomerizes glucose-6-phosphate to fructose-6-phosphate.

  • B. Hexokinase

    Hexokinase phosphorylates free glucose at glycolysis entry.

  • C. Pyruvate kinase

    Pyruvate kinase catalyzes the final ATP-producing glycolytic step.

  • D. Phosphofructokinase-1

    PFK-1 converts fructose-6-phosphate to fructose-1,6-bisphosphate.

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 A, Phosphoglucose isomerase. Phosphoglucose isomerase rearranges glucose-6-phosphate into fructose-6-phosphate, preparing the molecule for the committed phosphorylation step of glycolysis.

Why is "Hexokinase" not the answer?

Hexokinase phosphorylates free glucose at glycolysis entry.

Why is "Pyruvate kinase" not the answer?

Pyruvate kinase catalyzes the final ATP-producing glycolytic step.

Why is "Phosphofructokinase-1" not the answer?

PFK-1 converts fructose-6-phosphate to fructose-1,6-bisphosphate.

What concept does this question test?

It tests Carbohydrate metabolism in Biochemistry. The correct option holds because: Correct: this enzyme isomerizes glucose-6-phosphate to fructose-6-phosphate.

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.