Energy 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 · Energy metabolism

Sample item

What directly powers ATP synthase in oxidative phosphorylation?

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

The answer and the reasoning

A. Proton gradient across inner mitochondrial membrane

Electron transport pumps protons across the inner mitochondrial membrane, and their return through ATP synthase drives ATP formation.

Option by option

  • A. Proton gradient across inner mitochondrial membrane (correct)

    Correct: proton-motive force powers ATP synthase.

  • B. Glucose concentration in cytosol

    Glucose must first be metabolized.

  • C. Calcium stored in bone

    Bone calcium does not generate mitochondrial ATP.

  • D. Sodium gradient across plasma membrane

    Sodium gradient is not the mitochondrial ATP-synthase driver.

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 A, Proton gradient across inner mitochondrial membrane. Electron transport pumps protons across the inner mitochondrial membrane, and their return through ATP synthase drives ATP formation.

Why is "Glucose concentration in cytosol" not the answer?

Glucose must first be metabolized.

Why is "Calcium stored in bone" not the answer?

Bone calcium does not generate mitochondrial ATP.

Why is "Sodium gradient across plasma membrane" not the answer?

Sodium gradient is not the mitochondrial ATP-synthase driver.

What concept does this question test?

It tests Energy metabolism in Biochemistry. The correct option holds because: Correct: proton-motive force powers ATP synthase.

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 Energy 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.