What is the Difference Between Membrane Potential and Equilibrium Potential?

The difference between membrane potential and equilibrium potential lies in their definitions and the factors that influence them. Here are the key differences:

Membrane Potential: This refers to the difference in electric potential across the cell membrane of a quiescent cell. It is the result of the movement of several different ion species through various ion channels and transporters. The membrane potential is influenced by the concentration of ions on both sides of the cell membrane and the electrical gradient created by these ion concentrations.
Equilibrium Potential: This refers to the electric potential difference across the cell membrane that is in exact equilibrium with the concentration gradient for an ion. It is the electrical potential difference across the cell membrane that exactly balances the concentration gradient for a specific ion. Equilibrium potentials are calculated using the Nernst equation.

In summary, membrane potential is the difference in electric potential across the cell membrane, while equilibrium potential is the electric potential difference that balances the concentration gradient for a specific ion. The membrane potential is influenced by various ion species and their concentrations, whereas the equilibrium potential is determined by the concentration gradient for a specific ion.

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What is the Difference Between Membrane Potential and Equilibrium Potential?

Comparative Table: Membrane Potential vs Equilibrium Potential

Here is a table comparing membrane potential and equilibrium potential:

Feature	Membrane Potential	Equilibrium Potential
Definition	The actual electric potential difference across a cell membrane.	The specific electric potential difference across a cell membrane that balances the concentration gradient for an ion.
Measurement	Measured using two electrodes.	Calculated using the Nernst equation.
Role	Describes the difference in voltage between the inside and outside of a cell.	Represents the point at which there is no net movement of ions in either direction, and the system is considered to be in equilibrium.
Relationship	The membrane potential will tend to stay at the equilibrium potential for a cell with only one permeant ionic species.	The equilibrium potential can be used to predict ion movement by comparing the current membrane potential of the neuron with the ion's equilibrium potential.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.