BIOL 1090 Lecture Notes - Lecture 4: Glycolipid, Apoptosis, Integral
3 Dec 2014
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Lecture 4 - sept. 17, 2014: dynamic nature of biological membranes, transmembrane substance movement. Lipid-anchored proteins attach to a lipid in the bilayer. Peripheral membrane proteins associate with the surfaces of the lipid bilayer. Fig 4. 4: two leaflets have distinct lipid composition, in many plasma membranes, the outer leaflet contains glycolipids and glycoproteins (lipids and proteins with carbohydrate attached) Saturated lipids reduce fluidity: nature of lipids in membrane, temperature. Cell function: balance between ordered (rigid) structure and disordered structure allows: Dynamic interactions between membrane components (e. g. proteins can come together reversibly) liquid crystal state crystalline gel state. Ruffles on the plasma membrane of a moving cell. Membrane fluidity is crucial to cell function: membrane fluidity must be maintained, in response to changes in temperature*, lipid composition of membranes can be changed by, desaturation of lipids, exchange of lipid chains. Cholesterol regulates membrane fluidity: lipids move easily, laterally, within leaflet, lipid movement to other leaflet is slow.
