Biology 2581B Study Guide - Quiz Guide: Biological Membrane, Choline, Glycerol
3 Jun 2020
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Biological membranes consists of mainly lipids for structure and proteins. Biological membranes are a bilayer(= 2 layers of lipids) Transporter = binds molecules on the outside, changes form and then releases, this is against the concentration gradient and needs atp. Channel protein = requires no energy, goes with the gradient, ions (with a charge) Polar head group (choline(e. g. )(positively charged) and phosphate(negatively charged) Increase stability bilayer (cholesterol stiffens the lipid, is hydrophobic) Phospholipids have a natural tendency to form a bilayer, the hydrophobic parts get together and the polar parts sit in the water. Enzymes help with flipflopping, once in a while they need to switch places. Functions of these proteins are: transporters and channels (ions in nerve cells, communication between outside and intracellular (hormones, localization of proteins at cell surface (antibodies, localization of proteins at membrane in cytosol (enzymes) -helix, 20 amino acids through the membrane, can be more than 1 helix.
