1. The document discusses the electrical properties of cell membranes, including diffusion potential, equilibrium potential, and the Donnan effect. 2. Diffusion potential is the voltage difference established across a membrane when ions diffuse down their concentration gradient through selective permeable pathways. The Nernst equation is used to calculate equilibrium potential for a single ion based on its intracellular and extracellular concentrations. 3. The Goldman equation calculates membrane potential based on permeability and concentrations of multiple permeable ions. 4. The Donnan effect refers to the uneven distribution of charged particles across a semipermeable membrane containing impermeable ions, maintaining concentration gradients and establishing a membrane potential.