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 enzyme is the principal rate-limiting enzyme of glycolysis in most tissues?

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

The answer and the reasoning

C. Phosphofructokinase-1

Phosphofructokinase-1 commits fructose-6-phosphate to glycolysis and is tightly regulated by cellular energy status, making it the principal control point of this pathway.

Option by option

  • A. Glucose-6-phosphatase

    Glucose-6-phosphatase releases free glucose in liver and kidney.

  • B. Pyruvate carboxylase

    Pyruvate carboxylase supports gluconeogenesis rather than glycolysis.

  • C. Phosphofructokinase-1 (correct)

    Correct: PFK-1 is the key regulatory glycolytic enzyme.

  • D. Hexokinase

    Hexokinase traps glucose in many cells but is not the main committed-step regulator.

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 C, Phosphofructokinase-1. Phosphofructokinase-1 commits fructose-6-phosphate to glycolysis and is tightly regulated by cellular energy status, making it the principal control point of this pathway.

Why is "Glucose-6-phosphatase" not the answer?

Glucose-6-phosphatase releases free glucose in liver and kidney.

Why is "Pyruvate carboxylase" not the answer?

Pyruvate carboxylase supports gluconeogenesis rather than glycolysis.

Why is "Hexokinase" not the answer?

Hexokinase traps glucose in many cells but is not the main committed-step regulator.

What concept does this question test?

It tests Carbohydrate metabolism in Biochemistry. The correct option holds because: Correct: PFK-1 is the key regulatory glycolytic enzyme.

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.