BIO270H1 Lecture : Lecture 3
Document Summary
Control of intracellular conditions: organize intracellular pathways into subcellular compartments, physical separation of processes requires transfer mechanisms. Polar head group varies (choline, inositol, ethanolamine, serine) Fatty acid tails vary in length, saturation. Glycolipids also play a role in communication between cells. Note: the type of fa tail also affects membrane fluidity. More pe and ps phosphoglycerides in inner leaflet. More pc phosphoglycerides in the outer leaflet. Thicker phospholipids with longer fa tails; proteins with longer tm domains. More rigid micro-compartments; can organize signalling complexes. E. g. low temperatures increase van der waals forces between lipids and restrict movement. Membrane fluidity is adjusted by altering the lipid profile. Can be more than half of the membrane mass. Embedded in bilayer or span entire membrane. Interact with integral membrane proteins of glycolipids. Distinguished by 1. molecule transported, 2. direction of transport: nature of the carriers, 4. role of energy in the process. High [ ] low [ ]
