Endocrine pancreas: insulin secretion: practice question

A Physiology 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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Physiology · Endocrine pancreas: insulin secretion

Sample item

Which sequence describes how a rise in blood glucose triggers insulin secretion from the pancreatic beta cell?

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

The answer and the reasoning

C. Glucose metabolism raises ATP, closes K-ATP channels, depolarises the cell and opens voltage-gated calcium channels

Glucose enters the beta cell through GLUT2 and is phosphorylated by glucokinase, which acts as the glucose sensor. The rise in ATP closes ATP-sensitive potassium channels, causing depolarisation and calcium influx, which triggers exocytosis of insulin granules. Sulfonylureas act by closing the same channel.

Option by option

  • A. Glucose enters through GLUT4 and activates a tyrosine kinase receptor

    Beta cells use GLUT2, and GLUT4 is the insulin-dependent transporter in muscle and fat.

  • B. Glucose lowers ATP, opens K-ATP channels and hyperpolarises the cell

    A fall in ATP opens the K-ATP channel and would suppress insulin release.

  • C. Glucose metabolism raises ATP, closes K-ATP channels, depolarises the cell and opens voltage-gated calcium channels (correct)

    Correct. This is the K-ATP channel pathway used by sulfonylureas.

  • D. Glucose binds a surface receptor that activates adenylyl cyclase and opens potassium channels

    Glucose acts through its metabolism, not a surface receptor.

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 Physiology question

What is the answer to this Physiology question?

The best answer is C, Glucose metabolism raises ATP, closes K-ATP channels, depolarises the cell and opens voltage-gated calcium channels. Glucose enters the beta cell through GLUT2 and is phosphorylated by glucokinase, which acts as the glucose sensor.

Why is "Glucose enters through GLUT4 and activates a tyrosine kinase receptor" not the answer?

Beta cells use GLUT2, and GLUT4 is the insulin-dependent transporter in muscle and fat.

Why is "Glucose lowers ATP, opens K-ATP channels and hyperpolarises the cell" not the answer?

A fall in ATP opens the K-ATP channel and would suppress insulin release.

Why is "Glucose binds a surface receptor that activates adenylyl cyclase and…" not the answer?

Glucose acts through its metabolism, not a surface receptor.

What concept does this question test?

It tests Endocrine pancreas: insulin secretion in Physiology. The rise in ATP closes ATP-sensitive potassium channels, causing depolarisation and calcium influx, which triggers exocytosis of insulin granules. Sulfonylureas act by closing the same channel.

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 Endocrine pancreas: insulin secretion?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.