Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference?

a. Resting membrane potential (RMP)

b. Threshold potential

c. Action potential

d. Positive membrane potential

The correct answer would be a. Resting membrane potential (RMP).

Resting membrane potential (RMP) refers to the potential difference found across the cell membrane of cell at rest.

It is created due to the unequal distribution of ions (such as Na⁺, K⁺, Cl⁻, Ca⁺⁺ etc) across the plasma membrane. It depends on the concentration gradient of ions across the plasma membrane as well as on its permeability for each type of ion.

The value of RMP may vary with the type of cell for example, RMP for neuron is around - 70 mV, for skeletal muscle it is around - 90 mV etc. Negative value suggests that there is an excess of negative charge inside the cell as compared to the outside of the cell.