BIOL 2070H Lecture Notes - Lecture 2: Micelle, Cell Signaling, Oligosaccharide
Document Summary
Development of plasma membrane pivotal moment in evolution of cells. But without a plasma membrane around it it"s not really considered a cell. Semipermeable membrane that takes advantage of amphipathic phospholipids to restrict charged or large particles through the membrane. Variety of proteins embedded that allow controlled movement. Lipid bilayer acts as a 2d solvent for membrane proteins. Arranged so tails are together and heads are around them interacting with the aqueous environment. Membrane is fluid so materials embedded can move around. Most common phospholipid in cell membranes is phosphatidylcholine. Other important phospholipids are phosphatidylserine, cholesterol, galactocerebroside. Cholesterol fills in gaps that are formed by unsaturated fatty acid chains and helps provide stability. Usually a difference between the outer side of the membrane and the inner side of the membrane. Phosphatidylcholine and sphingomyelin are mostly found on the outside. Phosphatidylserine, phosphatidylethanolamine, and phosphatidylinositol are mostly on the inside.
