Final answer:
The membrane potential is closer to EK due to higher potassium conductance (gK) compared to sodium conductance (gNa), and potassium's role in establishing the resting membrane potential.
Step-by-step explanation:
If in a typical cell gK (potassium conductance) is much greater than gNa (sodium conductance), the membrane potential of the cell will be closer to EK (the equilibrium potential for potassium) rather than ENa (the equilibrium potential for sodium).
This is because the permeability of the membrane to potassium ions is significantly higher, which means that the movement of potassium ions across the membrane has a greater effect on the membrane potential. Potassium ions tend to leave the cell, obeying their concentration gradient, and in doing so create a negative charge within the cell. This helps to establish the resting membrane potential, which is typically around -70 mV. The Na+/K+ ATPase, also known as the sodium-potassium pump, helps maintain this potential by actively transporting K+ ions into the cell and Na+ ions out of the cell, but the greater conductance for K+ is what makes the membrane potential closer to EK.