BIOL 200 Lecture Notes - Lecture 6: Phosphatidylcholine, Flippase, Phosphatidylserine
Document Summary
Topic 2. 2 the lipid bilayer (cid:862)the (cid:373)e(cid:373)(cid:271)ra(cid:374)e is a bilayer(cid:863) Phospholipids are amphipathic and have the right shape (two tails) to form bilayers. Hydrophilic head: polar group + phosphate + glycerol. Two hydrophobic fatty acid tails (cid:862)the (cid:373)e(cid:373)(cid:271)ra(cid:374)e is organized but fluid(cid:863) Membrane anchor protein graph shows no recovery (not going anywhere) Freely diffused protein graph would show steeper recovery. At cold temperatures: (cid:373)e(cid:373)(cid:271)ra(cid:374)e (cid:271)ilayers (cid:858)freeze(cid:859, assume a more ordered, crystalline-like state, very low fluidity, very fragile. At warmer temperatures, the structure will be more fluid (creates holes/pores). A cell could change its lipids to maintain appropriate fluidity: degree of unsaturation of lipids less saturated tails (=more double bonds) increase fluidity, fatty acid tail length, amount of sterol in the membrane. Important note: plant and fungi use these tactics far more than animals. Fatty acid tail length: fa tail length: 14-24c m, most common: 18-20c, shorter tails (<18c) more fluid.
