LIFE 102 Lecture Notes - Lecture 5: Lipid Raft, Lipid Bilayer, Biological Membrane
19 Sep 2016
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Document Summary
Concepts: biological membranes consist of a lipid bilayer along with many membrane proteins. Biological membranes are selectively permeable with membrane proteins determining what moves across membranes. Diffusion of water across (osmosis) can affect cell structure and variability. Amphipathic: a hydrophilic and a hydrophobic region (molecular bipolar syndrome). Form lipid bilayers with charged heads oriented toward water, hydrophobic tails on the inside. Lipids and proteins can move laterally (in the plane of, in 2 dimensions) in membranes. Lipids can also move in membranes - how fast they move depends on the degree of saturation of the fatty acids in the lipids. Cell membrane: (ecm on outside (has lots of carbohydrates and collagen) cytoskeleton on inside) Membrane proteins: (amphipathic due to polar and charged amino acids) Aquaporin: a protein that forms a water channel in a membrane. Integral proteins: pass through the membrane = transmembrane. Cholesterol serves to stabilize membrane fluidity; a fluidity buffer.
