BIOCH200 Lecture Notes - Lipid Bilayer, Flippase, Cholesterol

• School: University of Alberta
• Department: Biochemistry
• Course: BIOCH200
• Professor: Walter Dixon

Document Summary

Bioch 200 biological membranes (con"t) (march 14, 2014) *cholesterol helps maintain both fluidity and stability of the lipid bilayer: *help maintain rigidity: by reducing rotational capabilities of the acyl tails at high temperatures, *help maintain fluidity: by preventing close chain-packing between acyl chains in cold temperatures. *transition temperature temperature at which the lipid membrane turns from a crystalline state to a more fluid state: *remember, the lipids are held together by hydrophobic interactions . *takes a lot of energy to transport the hydrophilic head through the hydrophobic region to the other membrane: membrane bilayer exhibits lipid asymmetries due to the nature in which they were transported there from the er. *types of membrane proteins: 1) integral membrane protein. Ex. ion channels: 2) peripheral membrane protein. *not actually incorporated with the membrane, just closely associated to it. Ex. spectrin proteins that provide membrane stability in rbc: 3) lipid-linked proteins. Lipid anchored so it can move laterally across membrane.