The resting membrane potential of a cell is -85 mV.The intracellular and extracellular concentrations of several ions are indicated in the following table,as is the calculated Nernst equilibrium potential (E_i)for each of these ions: The membrane has channels for Na⁺,K⁺,Cl^-,and Ca⁺⁺.The conductance of the membrane is the greatest for which ion? A)Na⁺ B)K⁺ C)Cl^- D)Ca⁺⁺

Question

Quizplus · Accepted Answer

The greatest conductance of the membrane will be for the ion that has the smallest difference between the resting membrane potential (-85mV) and its Nernst equilibrium potential. Based on the given table, the Nernst equilibrium potential for K+ is the closest to the resting membrane potential (-94 mV), which means that the conductance for K+ will be the greatest compared to the other ions. Therefore, the best choice is B) K⁺.

The Resting Membrane Potential of a Cell Is -85 MV