Final answer:
The resting membrane potential is around -70 mV and is characterized by a negative charge inside the cell due to the movement of K+ out of the cell, leaving behind negatively charged proteins. The positive charge is maintained outside the cell with a higher concentration of Na+. A membrane acts like a capacitor, and ion channels and pumps maintain this potential.
Step-by-step explanation:
The resting membrane potential is the electric charge difference across the cell membrane when the cell is in a non-excited state. In neurons, this is typically around -70 millivolts (mV), with the inside of the cell being more negative relative to the outside. The negative charge inside the cell is primarily due to the movement of potassium ions (K+) out of the cell, which leave behind a surplus of negatively charged proteins. The exterior of the cell, in contrast, has a higher concentration of positive sodium ions (Na+). These ion gradients are maintained by the selectively permeable membrane which has more leakage channels for K+ than Na+, and by the active transport performed by the sodium-potassium pump, which expels more positive ions (3 Na+) from the cell than it brings in (2 K+).
The membrane acts like a capacitor, storing charge and having the ability to discharge it when the membrane potential changes, as it does during the formation of an action potential. Leakage channels and the sodium-potassium pump work to balance the movement of ions to maintain the resting membrane potential, preventing the equalization of charges on both sides of the membrane.