Consider a phospholipid vesicle containing 10 m M Na^+ ions....

Consider a phospholipid vesicle containing $10 \mathrm{m} M \mathrm{Na}^{+}$ ions. The vesicle is bathed in a solution that contains $52 \mathrm{mM} \mathrm{Na}^{+}$ ions, and the electrical potential difference across the vesicle membrane $\Delta \psi=\psi_{\text {outside }}-\psi_{\text {inside }}=-30 \mathrm{mV} .$ What is the electrochemical potential at $25^{\circ} \mathrm{C}$ for $\mathrm{Na}^{+}$ ions?

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Nernst Equation

This is a fundamental relation that combines the chemical and electrical terms to describe the equilibrium condition for ion movement across membranes. It allows the determination of the equilibrium potential for a given ion by setting the total electrochemical potential difference to zero, balancing the diffusion and electrical forces.

Electrochemical Potential

This is the sum of the chemical potential and the electrical potential energy of an ion. In membranes or similar systems, it is used to describe the total driving force for the movement of ions, taking into account both the concentration gradient (which drives diffusion) and the electrical gradient (which drives ions according to charge).

Chemical Potential

This term accounts for the effect of the concentration of ions on their energy, typically expressed as RT ln([ion]). It represents the energy change associated with adding an extra ion to a system and drives diffusion from high to low concentration.

Electrical Potential

This refers to the energy associated with the charge of the ion in an electric field, and it is given by zF?, where z is the ion’s charge, F is Faraday’s constant, and ? is the electric potential. It is a crucial component in scenarios where ions experience a voltage difference, such as across cellular membranes.

Transcript

Please give Ace some feedback