Biochemistry 2280A Lecture Notes - Lecture 9: Lipid Bilayer, Passive Transport, Cholesterol

• School: Western University
• Department: Biochemistry
• Course: Biochemistry 2280A
• Professor: Derek Mc Lachlin

Document Summary

Biochemistry lecture 9 october 1, 2018. Cholesterol can help with packing of the lipid bilayer. At low temperatures, cholesterol can inhibit the packing and make the membrane more. If a membrane has more cholesterol than another; it will be less fluid. Whe(cid:374) we say (cid:858)asy(cid:373)(cid:373)etrical(cid:859) we (cid:373)ea(cid:374) the identity of the polar head groups. Enzymes can be used to flip lipids back. Glycolipids are facing away from the cytosol: composition of membranes, by mass. Usually about 50% lipids and 50% proteins (with a sliver of carbohydrates: functions of membrane proteins. Transporters and channels moving things across the membrane. Receptors a cell can detect signals from outside and send them across the membrane into the cell, respond to specific signals. Membranes are not passive barriers: facilitated transport. Transporters specific binding site, conformational changes during transport. Channels open pathway, discriminating based on size and charge: active vs passive transport. Concentration gradients (electrochemical gradients) are driving forces behind passive transport.