Membrane potential (or transmembrane potential or transmembrane potential ifference or transmembrane potential gradient), is the electrical potential difference (voltage) across a cell's plasma membrane. The plasma membrane surrounds the cell to provide a stable environment for biological processes. Membrane potential arises from the action of ion transporters embedded in the membrane which maintain viable ion concentrations inside the cell. The term "membrane potential" is sometimes used interchangeably with cell potential but is applicable to any lipid bilayer or membrane.