What is the Difference Between Nernst Potential and Membrane Potential?

The Nernst potential and membrane potential are related concepts in cellular electrophysiology, but they describe different aspects of electrical potential differences across a cell's membrane.

Nernst Potential:

The Nernst potential is the equilibrium potential for a specific ion, calculated using the Nernst equation.
It describes the electrochemical equilibrium in terms of the reversal potential for an ion.
The Nernst potential is determined by the concentration of ions inside and outside the cell, as well as the temperature.

Membrane Potential:

The membrane potential is the difference in voltage (or electrical potential) between the inside and outside of a cell.
It is defined as the electrical potential difference across the plasma membrane when the cell is in a non-excited state.
The membrane potential is influenced by various factors, including the concentration of ions inside and outside the cell, the permeability of the membrane, and the movement of ions across the membrane.

In summary, the Nernst potential is a specific calculation to determine the equilibrium potential for a particular ion, while the membrane potential is a broader term that describes the overall electrical potential difference between the inside and outside of a cell.

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What is the Difference Between Nernst Potential and Membrane Potential?

Comparative Table: Nernst Potential vs Membrane Potential

The membrane potential and Nernst potential are important concepts in biochemistry and electrochemistry. Here is a table comparing the key differences between them:

Feature	Membrane Potential	Nernst Potential
Definition	Membrane potential (also known as transmembrane potential or membrane voltage) is the difference in electrical charge between the inside and the outside of a cell. It typically ranges from -40 mV to -80 mV.	Nernst potential (also known as reversal potential) is the potential across a cell membrane that would be required for a specific ion to have no net movement across the membrane.
Function	Membrane potential has two basic functions: allowing a cell to function as a battery and transmission of signals between different parts of a cell.	Nernst potential is used to determine the equilibrium potential for a specific ion, which is important for understanding ion transport and membrane potential.
Equation	Membrane potential is determined by various factors, including the concentration of ions inside and outside the cell, and their permeability across the membrane.	The Nernst equation is used to calculate the equilibrium potential for a specific ion (Vm = equilibrium potential for any ion [V]; z = valence of the ion, [C]0 = concentration of ion X outside of the cell [mol]; [C]i = concentration of ion X inside the cell [mol]).
Applications	Membrane potential is crucial for understanding how cells maintain their electrical charge and how they transmit signals.	Nernst potential is useful in biochemistry and electrochemistry, particularly in determining the equilibrium potential for specific ions in electrochemical cells.

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.