BIOL 112 Lecture Notes - Sucrose, Lipid Bilayer, Cell Membrane

• School: McGill University
• Department: Biology (Sci)
• Course: BIOL 112
• Professor: Frieder Schoeck

Document Summary

Membrane structure: leaflet - describes one layer of the bilayer. Cholesterol - inside lipid bilayer: solidifies the cell membrane, decreases fluidity. Bilayer: self assembles since it is energetically favourable, self assemble into a cell. Transmembrane proteins: have hydrophobic regions of amino acids, cross phospholipid bilayer, have a specific orientation - 2 different faces on each side of membrane bilayer. Peripheral membrane proteins: not hydrophobic, not embedded in bilaryer, covalently attached to lipids or bind non-covalently to other transmembrane proteins. These function as transportation of molecules, signal transduction, energy generation, and cell adhesion. Diffusion: passive mixing of substances across a concentration gradient: due to brownian motion - randomly distribute - and a concentration gradient, determined by distance, temperature, size and steepness of concentration gradient. Osmosis: diffusion of water across a selectively permeable membrane, water will move to right until there is an equilibrium, form low conc. to high conc.