BIOB10H3 Lecture Notes - Lecture 5: Electrochemical Gradient, Fluid Mosaic Model, Glycosylphosphatidylinositol
4 Oct 2016
School
Department
Course
Professor
Document Summary
Functions of the plasma membrane (5-10 nm thick): compartmentalization- encloses and protects contents of the cell, scaffold for biochemical activities- for enzyme and signalling proteins. Lipid bilayer : danielli and davson (1930"s)- proposed proteins were in lipid bilayer. Globular proteins lining surfaces and lining channels to form pores: electron microscopy (1950"s)- confirmed proteins in the bilayer, singer and nicolson (1972)- fluid mosaic model . Composition of the plasma membrane: membrane lipids 2) membrane carbohydrates 3) membrane proteins, membrane lipids: a) phospholipids b) sphingolipids c) cholesterol, phospholipids: glycerol + 2 fatty acids + phosphate group + polar group. Phosphate and polar group make the head phosphoglycerides have an additional group linked to the phosphate, most commonly either choline (forming phosphatidylcholine, pc), ethanolamine (forming phosphatidylethanolamine, pe), serine (forming phosphatidylserine, ps), or inositol (forming phosphatidylinositol, pi). Pi3 kinase converts pi to pi3p: sphingolipids- single fatty acid chain. Sugar added (glycolipid) eg. cerebroside - has an insulating function.
