Biology Nervous Coordination SZABMU 2023
PMDC Verified Question 41 of 86
During non-conducting state, the neuron membrane is permeable to efflux of:
A
K⁺
B
Na⁺
C
Ca⁺⁺
D
Cl⁻
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: K⁺
Concept:

The resting membrane potential is largely dictated by "leak" channels that remain open when the neuron is idle.

Solution:

  • In a non-conducting (resting) state, the neuronal membrane contains significantly more open potassium leak channels than sodium leak channels. Therefore, it is highly permeable to the slow, continuous efflux of potassium ions (\(\text{K}^+\)) moving down their concentration gradient out of the cell.


Why other options are incorrect:

  • \(\text{Na}^+\) / \(\text{Ca}^{2+}\): Their voltage-gated channels are strictly closed during the resting state to maintain the electrochemical gradient.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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