PHGY 209 Lecture Notes - Lecture 3: Cell Adhesion, Osmosis, Cytoskeleton
14 Oct 2017
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Document Summary
> bimolecular phospholipid layer molecules exhibit lateral mobility. Phospholipid = hydrophilic head (charged) + hydrophobic tail (uncharged) * both tails point towards each other in cell membrane. * phospholipids amphipathic: molecule with charge at one end (head) and no charge on the other end (tail) Cholesterol: strengthens and contributes to impermeability of membrane; provides stability and rigidity (inserted in phospholipid layer) * adds flexibility to membrane by interfering with the crystallization of phospholipid tails. * forms lipid rafts where complex functional groups and ion channels congregate in cell membrane. * integral closely associated with phospholipids; mostly across the membrane (transmembrane) * peripheral more loosely associated; mostly on cytoplasmic side. Glycocalyx: composed of carbohydrates and glycoproteins on outer side of membrane. Ion channels allows ions to move across cell membrane (diffusion) Transporters moves molecules across cell membrane (conformational change) Transmembrane transport pathways: via phospholipid bilayer, via interaction with protein cluster (channel or carrier)
