Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Cell Membrane Haixu Tang School of Informatics Membrane Lipids Are Amphipathic Molecules hydrophilic and hydrophobic molecules interact differently with water Packing arrangements of lipid molecules The spontaneous closure of a phospholipid bilayer Phospholipid mobility The other composition of membrane Cholesterol and glycolipids It inhibits possible phase transitions: (1) decreases the permeability of the bilayer to small water-soluble molecules; (2) prevents the hydrocarbon chains from coming together and crystallizing. Cholesterol Glycolipid Four major phospholipids in mammalian plasma membranes Cell wall Lipid raft The asymmetrical distribution of phospholipids and glycolipids Functions of phospholipids in cell signaling Membrane proteins Membrane attachment of Water soluble proteins Transmembrane polypeptide chain crossing the lipid bilayer Using hydropathy plots to localize potential ahelical membrane-spanning segments b-barrels (occasionally) Solubilizing membrane proteins with a mild detergent Two detergent Reconstituting functional membrane protein system Red cell membrane Preparing red cell ghosts SDS polyacrylamide-gel electrophoresis pattern of the proteins in the human red blood cell membrane Three major ways of proteins association with membranes • Noncovalently Associated with the Cytosolic Side: Spectrin • Extends Through the Red Blood Cell Lipid Bilayer as a Single a Helix: Glycophorin • Multipass Membrane Protein: Band 3 protein Spectrin: cytoskeleton protein Spectrin-based cytoskeleton Glycophorin: single pass membrane proteins Band 3: Anion Transporter The polypeptide chain (about 930 amino acids long) is thought to extend across the bilayer 12 times. Photosynthetic reaction center The Cell Surface Is Coated with Sugar Residues Carrier proteins and channel proteins A typical ion channel The gating of ion channels Potassium ion gate Passive and active transport Three ways of driving active transport