BIOL 1020 Lecture Notes - Lecture 9: Hydrophile, Endomembrane System, Histocompatibility

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 1020
• Professor: Michael P.Shaw

Document Summary

Biology 1020- lecture 9 plasma membrane structure and function. Early model of plasma membrane structure: sandwich model (davson and danielli 1930s) Membranes were found to contain protein and lipids and were chemically analyzed. Knew through other methods that it was a phospholipid bilayer. Davson and danielli (1930s: they thought that the lipid bilayers were sandwiched between proteins so hydrophilic proteins then could interact with the aqueous extracellular space and with the cytoplasm which is also aqueous. Plasma membrane: fluid mosaic model (singer and nicolson, 1972) Evidence: freeze fracture of the membrane. This method splits the membrane in half alone the middle of the phospholipid bilayer: take a cell, freeze it in ice, you will then have an extracellular layer and the cytoplasmic layer. Membrane proteins in the two layers: extracellular has less than the cytoplasmic layer the fluid in the fluid mosaic model. Most of the lipids, and some proteins, drift laterally.