The resting membrane potential is A) much closer to the equilibrium potential for Na⁺ than to the equilibrium potential for K⁺. B) much closer to the equilibrium potential for K⁺ than to the equilibrium potential for Na⁺. C) is always -90mV D) both (a) and (c) above. E) both (b) and (c) above.

Question

Quizplus · Accepted Answer

The resting membrane potential is mostly determined by the balance between the ion fluxes of potassium and sodium. Since the membrane is more permeable to potassium, the equilibrium potential for potassium plays a larger role in determining the resting membrane potential. Therefore, the resting membrane potential is much closer to the equilibrium potential for K⁺ than to the equilibrium potential for Na⁺. Choice (C) is incorrect because the resting membrane potential can vary depending on the cell type and conditions. Choice (A) is incorrect because the opposite is true - the equilibrium potential for sodium is further from the resting membrane potential than the equilibrium potential for potassium. Choice (D) and (E) are incorrect for the same reasons.

The Resting Membrane Potential Is