Bioelectricity refers to electrical potentials and currents occurring within or produced by living organisms. It results from the conversion of chemical energy into electrical energy. Bioelectric potentials are generated by a number of different biological processes, and are used by cells to govern metabolism, to conduct impulses along nerve fibers, and to regular muscular contraction. In most organisms bioelectric potentials vary in strength from one to several hundred millivolts. The most important difference between bioelectric currents in living organisms and the type of electric current that is used to produce light, heat, or power is that a bioelectric current is a flow of ions, while standard electricity is a movement of electrons.