<prompt> Equilibrium potential for an ion is calculated by:Gibbs Donnan EquilibriumNernst EquationGoldman EquationNone of the above  <response>: Gibbs Donna Equilibrium explains unequal distribution of ions in ICF and ECF due to non- diffusible anions proteins present intracellularly Nernst Equation: Nernst equilibrium potential at which there is no net transpo of the molecule across the membrane Where, R the gas constant T temperature in degrees Kelvin ln natural logarithm i the concentration of X inside the cell o the concentration of X outside the cell zx the valence of charged molecules F the Faraday constant Vm the membrane potential The Nernst equation, at 37degC, can be written for univalent ion as follows: If movement of ion is producing negativity inside the cell membrane, Nernst potential will be with negative sign and vice-versa Goldman-Hodgkin-Katz GHK equation state that when a membrane is permeable to several different ions, the diffusion potential that develops depends on three factors: polarity of the electrical charge of each ion permeability of the membrane P to each ion concentrations C of the respective ions on the inside i and outside o of the membrane 