Jan 12th - The Plasma Membrane & Cellular Transport

Jan 12th The - The Plasma Membrane Cellular Transport Jan 12th Fluid mosaic model of membrane structure Plasma Membrane defines extent of cell

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Jan 12 th Fluid mosaic model of membrane structure Plasma Membrane - defines extent of cell; fragile selective, semi-permeable barrier. Phospholipid layer – has phospholipid hairs on the outside of the cells, and the heads on the inside of the side (they are hydrophobic: scared of water, move away from water) Plasma membrane considered a fluid Phospholipids o Glyercol backbone with two fatty acids+phosphate containing groups o Made of glycerol, long chain fatty acids: most of them are poly unsaturated fatty acids, with at least 2 or more double bonds o Poly unsaturated fatty acids = increase membrane fluidity o Saturated fatty acids = more stable, less fluid, involved in cell signaling ( lipid rafts) o Lipid rafts involved in receptor mediated signal transduction o Cholesterol Mosaic structure of plasma membrane – proteins dispersed in the lipid bilayer those that are no anchored constantly change their position. Proteins Two classes of membrane proteins 1. Integral membrane proteins – embedded within 2. Perpherial membrane protein – loosely attached Function Transport Enzymatic activity Receptors for signal transduction – cannot bind to the cell Intercellular joining – form hooks to make sure they are attached, glycoproteins works like Velcro Cell-cell recognition Attachment to the cytoskeleton and extracellular matrix Carbohydrates Located primarily on membrane outer surface Overall function of membrane Protects cells from external environment, cell barrier only letting some things in and some things out Cellular joining, attachment and communication Transport, membrane semi-permeable – lipid layer, fat acids, and vitamins (A,C,K,D) can move through the phospholipid bilayer easily
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This note was uploaded on 02/27/2012 for the course ANP 1105 taught by Professor Carnegie during the Winter '08 term at University of Ottawa.

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Jan 12th The - The Plasma Membrane Cellular Transport Jan 12th Fluid mosaic model of membrane structure Plasma Membrane defines extent of cell

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