Final answer:
The Nernst equation predicts the membrane potential resulting from permeability to a single ion, important for understanding the voltage across cell membranes.
Step-by-step explanation:
The Nernst equation predicts the membrane potential resulting from permeability to a single ion. This equation takes into account the concentrations of ions on both sides of a semipermeable membrane, such as the cell membrane, and allows the calculation of the potential difference or voltage across it. Specifically, it can be used for determining the equilibrium potential (also known as the reversal potential) for a particular ion based on the concentration gradient across the membrane.
In a biological context, such as in neuron cells, the resting membrane potential is established by the differential permeability of the membrane to certain ions and their respective concentration gradients. The Nernst equation is essential in understanding how changes in ion concentrations, both intracellular and extracellular, can affect the membrane potential. However, it is worth noting that while the Nernst equation calculates the potential for individual ions, the actual membrane potential of a cell at any given time is determined by the combined effect of all permeable ions, which is described by the Goldman equation.