Biochemistry 3381A Study Guide - Quiz Guide: Fluid Mosaic Model, Lipid Bilayer, Cell Membrane
27 May 2020
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Document Summary
Fluidity affected by degree of saturation, motion of phospholipids, temperature, sterol- cholesterol. Lipid bilayer don"t fuse spontaneously in water as the phosphate heads in cytoplasmic monolayer will bind with water that need to be displaced for the bilayers to fuse. Cell membrane fusion is regulated fusion proteins, which force appropriate membranes into tight proximity, squeezing out the water layer that keeps the bilayers apart. Rotation of phospholipid occurs across the long axis. Flip-flop between the two monolayers is rare, but happens in cholesterol frequently. Lateral diffusion- changing places within the monolayer/ leaflet. Phospholipids are manufactured in one monolayer only, in cytosolic monolayer in e. r membrane. If the phospholipids don"t travel reasonably as flip-flop is rare there wouldn"t be a second layer. This is solved by phospholipid translocators/ flippases that ensure flip-flop movement. The lipid compositions of the inner and outer monolayers are different, reflecting the different functions of the two layers of a cell membrane.
