Biochemistry 2280A Lecture Notes - Lecture 10: Cytoskeleton, Hydrophile, Peripheral Membrane Protein
12 Dec 2016
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Topic 7 continued: lipids can diffuse within the bilayer. Movement in the x/y direction, but not in the z-direction. They do move around, they"re not static and how fast they move around = fluidity. Organism must maintain some kind of fluidity, can"t be rigid. Longer the chain, the more attraction the chains have for each other because of van der waals forces = harder it is to get past each other. More double bonds = more kinks = prevents lipids from packing together = promotes fluidity. Organism can control the fluidity by controlling these aspects: cholesterol and membrane fluidity. Characteristics of cholesterol differ based on temperature. At 37degrees celsius, cholesterol fills spaces between phospholipids = decrease fluidity. At low temperature, cholesterol inhibits packing of phospholipids = increase fluidity. Composition of head groups on the bilayer is different on each side. Cell has proteins that are designed to maintain the asymmetry.
