Nernst Potential and Equation

Nernst Potential

Definition

• The Nernst potential is the potential difference across a cell membrane that exactly balances the tendency of an ion to diffuse due to its concentration gradient.

Formula

• The Nernst potential (E) can be calculated using the Nernst equation:

E = (RT/nF) \* ln(C2/C1)

• Where:
  • E = Nernst potential (in volts)
  • R = gas constant
  • T = temperature in Kelvin
  • n = charge of the ion
  • F = Faraday's constant
  • C2 and C1 = concentrations of the ion inside and outside the cell, respectively

Calculation of Nernst Potential for Specific Ions

• Sodium (Na+): E = 61.5 mV * log([Na+]out / [Na+]in)
• Potassium (K+): E = -85.5 mV * log([K+]out / [K+]in)
• Chloride (Cl-): E = -71.5 mV * log([Cl-]out / [Cl-]in)

Importance

• The Nernst potential is crucial in understanding the resting membrane potential of a cell, as it determines the direction and magnitude of ion fluxes across the cell membrane.
• It plays a key role in regulating various cellular processes, including muscle contraction, nerve impulses, and cell signaling.

Nernst Potential

Definition

• The Nernst potential is the potential difference that balances the tendency of an ion to diffuse due to its concentration gradient across a cell membrane.

Formula

• The Nernst potential (E) can be calculated using the Nernst equation: E = (RT/nF) * ln(C2/C1)
• The variables in the Nernst equation are:
  • R: gas constant
  • T: temperature in Kelvin
  • n: charge of the ion
  • F: Faraday's constant
  • C2 and C1: concentrations of the ion inside and outside the cell, respectively

Ion-Specific Calculations

Sodium (Na+)

• The Nernst potential for sodium ions can be calculated using the equation: E = 61.5 mV * log([Na+]out / [Na+]in)

Potassium (K+)

• The Nernst potential for potassium ions can be calculated using the equation: E = -85.5 mV * log([K+]out / [K+]in)

Chloride (Cl-)

• The Nernst potential for chloride ions can be calculated using the equation: E = -71.5 mV * log([Cl-]out / [Cl-]in)

Importance

• The Nernst potential determines the direction and magnitude of ion fluxes across the cell membrane.
• It plays a crucial role in regulating cellular processes, including:
  • Muscle contraction
  • Nerve impulses
  • Cell signaling

Learn about the Nernst potential, a crucial concept in cell membrane biology, and how to calculate it using the Nernst equation. Understand the formula and its components.