BSC 2010 Chapter Notes - Chapter 5: Peripheral Membrane Protein, Lipid Bilayer, Membrane Fluidity
15 Feb 2016
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Document Summary
Unsaturated fatty acids make for a less dense, fluid packing. Membrane fluidity is affected by: lipid composition. Cholesterol and long-chain saturated fatty acids pack tightly and make the membrane less fluid: temperature. All biological membranes contain proteins: about 1 protein for every 25 phospholipid molecules. Peripheral membrane proteins: lack exposed hydrophobic groups, not embedded in the bilayer, have polar regions that interact with exposed parts of integral membrane proteins. Integral membrane proteins: partly embedded in the bilayer, have hydrophilic and hydrophobic regions, transmembrane protein- protrudes on both sides of the bilayer. Membrane proteins and lipids generally interact only noncovalently. Glycolipid- carb covalently bonded to a lipid. Glycoprotein- one or more carb chains covalently bonded to a protein. Proteoglycan- protein with even more carb molecules attached to it; carb chains are usually longer than in glycoproteins. Speed of diffusion depends on 3 factors: diameter of molecule, temperature of the solution, concentration gradient in the system.
