Membrane physiology: 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 · Membrane physiology

Sample item

What is the main determinant of resting membrane potential in many cells?

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

The answer and the reasoning

A. Potassium permeability through leak channels

Resting membrane potential is dominated by potassium leak conductance because the membrane is much more permeable to potassium than sodium at rest.

Option by option

  • A. Potassium permeability through leak channels (correct)

    Correct: potassium diffusion largely sets the resting voltage.

  • B. Chloride secretion into sweat

    Sweat chloride secretion does not determine neuronal resting potential.

  • C. Sodium influx through voltage-gated channels

    Voltage-gated sodium channels drive the action potential upstroke.

  • D. Calcium release from sarcoplasmic reticulum

    Sarcoplasmic calcium release initiates contraction in 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 Physiology question

What is the answer to this Physiology question?

The best answer is A, Potassium permeability through leak channels. Resting membrane potential is dominated by potassium leak conductance because the membrane is much more permeable to potassium than sodium at rest.

Why is "Chloride secretion into sweat" not the answer?

Sweat chloride secretion does not determine neuronal resting potential.

Why is "Sodium influx through voltage-gated channels" not the answer?

Voltage-gated sodium channels drive the action potential upstroke.

Why is "Calcium release from sarcoplasmic reticulum" not the answer?

Sarcoplasmic calcium release initiates contraction in muscle.

What concept does this question test?

It tests Membrane physiology in Physiology. The correct option holds because: Correct: potassium diffusion largely sets the resting voltage.

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 Membrane physiology?

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.