Overview Structure bilayer of phospholipids asymmetrical in respect to intracellular and extracellular faces "fluid mosaic" composition cholesterol login to view 5 more bullets phospholipids login to view 1 more bullet sphingolipids login to view 5 more bullets glycolipids proteins login to view 39 more bullets Function Function selective permeability controls an intracellular environment distinct from extracellular environment signalling localization of enzymes to promote or inhibit interaction Membrane Physiology Electrochemical potential determined by conductance (G) login to view 3 more bullets net force login to view 6 more bullets Equilibrium potential defined as the electrical potential across a membrane that would prevent the diffusion of a substance via its concentration force for a given concentration difference across a membrane measured in millivolts (mV) for a single substance calculated by login to view 11 more bullets does NOT determine rate of ionic diffusion → only whether diffusion is favorable Resting membrane potential (Emem) equilibrium potential of most cells = -90 mV calculated by login to view 5 more bullets example Emem = -77 mV EK+ = -95 mV is diffusion of K+ across this membrane favorable? login to view 1 more bullet inside cells (as compared to extracellular environment) ↑ K+ login to view 5 more bullets ↓ Na+ login to view 4 more bullets ↓ Cl- login to view 2 more bullets