Glucose transport: GLUT4 in exercise: 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 · Glucose transport: GLUT4 in exercise

Sample item

A man with type 2 diabetes finds that his blood glucose falls after a brisk walk, even when circulating insulin is low. Which mechanism in skeletal muscle explains this?

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

The answer and the reasoning

D. Contraction-induced translocation of GLUT4 to the sarcolemma

Muscle contraction, acting through AMP-activated protein kinase and calcium signals, causes GLUT4 vesicles to fuse with the sarcolemma independently of insulin. Glucose uptake rises and insulin sensitivity improves, which is why regular exercise helps in type 2 diabetes.

Option by option

  • A. Increased expression of GLUT2

    GLUT2 is a hepatic, beta cell and basolateral intestinal transporter, not the muscle transporter.

  • B. Increased SGLT2 activity

    SGLT2 reabsorbs filtered glucose in the proximal renal tubule and is not expressed in muscle.

  • C. Activation of glucose-6-phosphatase

    Glucose-6-phosphatase would release glucose and is absent in muscle.

  • D. Contraction-induced translocation of GLUT4 to the sarcolemma (correct)

    Insulin-independent GLUT4 translocation increases glucose uptake into working muscle.

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 D, Contraction-induced translocation of GLUT4 to the sarcolemma. Muscle contraction, acting through AMP-activated protein kinase and calcium signals, causes GLUT4 vesicles to fuse with the sarcolemma independently of insulin.

Why is "Increased expression of GLUT2" not the answer?

GLUT2 is a hepatic, beta cell and basolateral intestinal transporter, not the muscle transporter.

Why is "Increased SGLT2 activity" not the answer?

SGLT2 reabsorbs filtered glucose in the proximal renal tubule and is not expressed in muscle.

Why is "Activation of glucose-6-phosphatase" not the answer?

Glucose-6-phosphatase would release glucose and is absent in muscle.

What concept does this question test?

It tests Glucose transport: GLUT4 in exercise in Biochemistry. Glucose uptake rises and insulin sensitivity improves, which is why regular exercise helps in type 2 diabetes.

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 Glucose transport: GLUT4 in exercise?

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.