BIOL 112 Lecture Notes - Lecture 5: Peripheral Membrane Protein, Integral Membrane Protein, Lipid Bilayer

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

Document Summary

Fluid mosaic o: can only move sideways, not up and down. Electro-microscopy o: the membrane splits because there is no hydrophobic interactions left, only van- der waals. Functions of membranes barrier transport: planar bilayers: artificial membranes o, artificial-membrane experiments. How rapidly can different solutes cross the membranes when: The passive mixing of substances resulting in transport along a concentration gradient. Random walk or brownian motion of individual molecules due to thermal motions and collisions: diffusion rates are determined by distance, temperature, molecule size and steepness of concentration gradient, osmosis. Diffusion of water across a selectively permeable membrane. Water moves from regions of low solute concentration to regions of high solute concentration. Why does drinking 200g of glucose doesn"t affect you like 200g of sodium chloride: glucose is a large molecule so the concentration gradient is much less steep, less individual ions. Passive transport: facilitated diffusion: facilitated diffusion depends on 2 types of membrane proteins.