Endocrinology: beta cell glucose sensing: 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.

Try it

Physiology · Endocrinology: beta cell glucose sensing

Sample item

Pancreatic beta cells release insulin in proportion to blood glucose. Which feature allows them to act as glucose sensors?

AUptake of glucose by insulin-dependent GLUT4BGLUT2 uptake with glucokinase, so the rate of glucose metabolism tracks plasma glucoseCDirect opening of potassium channels by glucose itselfDA glucose receptor on the cell surface coupled to a G protein

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

The answer and the reasoning

B. GLUT2 uptake with glucokinase, so the rate of glucose metabolism tracks plasma glucose

Beta cells take up glucose through GLUT2 and phosphorylate it with glucokinase, which has a high Km. Metabolism rises with plasma glucose, ATP increases, ATP-sensitive potassium channels close, the cell depolarises and calcium entry triggers insulin release.

Option by option

A. Uptake of glucose by insulin-dependent GLUT4
GLUT4 is insulin-dependent and found in muscle and fat, not in beta cells.
B. GLUT2 uptake with glucokinase, so the rate of glucose metabolism tracks plasma glucose (correct)
Correct. GLUT2 and glucokinase link glucose metabolism, and thus ATP production, to plasma glucose.
C. Direct opening of potassium channels by glucose itself
Glucose does not open potassium channels directly; ATP made from it closes them.
D. A glucose receptor on the cell surface coupled to a G protein
Glucose acts after metabolism and not through a surface G-protein coupled glucose 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.

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is B, GLUT2 uptake with glucokinase, so the rate of glucose metabolism tracks plasma glucose. Beta cells take up glucose through GLUT2 and phosphorylate it with glucokinase, which has a high Km.

Why is "Uptake of glucose by insulin-dependent GLUT4" not the answer?

GLUT4 is insulin-dependent and found in muscle and fat, not in beta cells.

Why is "Direct opening of potassium channels by glucose itself" not the answer?

Glucose does not open potassium channels directly; ATP made from it closes them.

Why is "A glucose receptor on the cell surface coupled to a G protein" not the answer?

Glucose acts after metabolism and not through a surface G-protein coupled glucose receptor.

What concept does this question test?

It tests Endocrinology: beta cell glucose sensing in Physiology. Metabolism rises with plasma glucose, ATP increases, ATP-sensitive potassium channels close, the cell depolarises and calcium entry triggers insulin release.

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 Endocrinology: beta cell glucose sensing?

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.