Biology 2382B Lecture Notes - Lecture 15: Alpha Helix, Antiporter, Membrane Potential
7 Apr 2016
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Document Summary
Amphipathic phospholipids in aqueous environment phospholipid bilayer. Dependent on fatty acid composition and temperature (but not in us! Mp increases with increasing chain length (more vdw between chains) Mp decreases with increasing unsaturation (causes kinks) Can also link membrane proteins to cytoskeleton or ecm (fixed protein = reduced mobility of things around it) Lateral diffusion occurs, but no flip-flopping between leaflets. Frap assay measures lipid/protein movement in membranes (fluidity) Bleach an area (this area is no longer fluorescent) Measure fluorescence recovery in the bleached area (how many proteins and their associated lipids laterally diffused into bleached area?) Cytosolic face: internal face of plasma membrane and external face of vesicle. Exoplasmic face: external face of pm and internal face of vesicle. Molecules that are both small and uncharged can pass (co2, o2, n2) Molecules that are large or charged molecules cannot pass (glucose, ions) Assymetry: inner and outer leaflets have different phospholipid composition.
