1、Chapter 4: Cell Membrane and Cell SurfaceI. Cell MembraneII. Cell Junctions III. Cell Adhesion IV. Extracellular Matrix http:/ Biomembranes: Their Structure, Chemistry and Functions Learning objectives:1. A brief history of studies on the structrure of the plasma membrane2. Model of membrane structu
2、re: an experimental perspective3. The chemical composition of membranes4. Characteristics of biomembrane5. An overview of the functions of biomembranes 1.1. A brief history of studieson the structrure of the plasmic membraneA. Conception:Plasma membrane(cell membrane),Intracellular membrane,Biomembr
3、ane.B. The history of studyOverton(1890s): Lipid nature of PM; J.D.Robertson(1959):The TEM showing:the trilaminar appearance of PM;Unit membrane model; S.J.Singer and G.Nicolson(1972): fluid-mosaic model; K.Simons et al(1997): lipid rafts model;Functional rafts in Cellmembranes. Nature 387:569-5722.
4、 Singer and Nicolsons Model of membrane structure: The fluid-mosaic model is the “central dogma” of membrane biology. A.The core lipid bilayer exists in a fluid state, capable of dynamic movement.B. Membrane proteins form a mosaic of particles penetrating the lipid to varying degrees.The Fluid Mosai
5、c Model, proposed in 1972 by Singer and Nicolson, had two key features, both implied in its name.3. The chemical composition of membranesA. Membrane Lipids: The Fluid Part of the ModelPhospholipids:Phosphoglyceride and sphingolipidsGlycolipidsSterols ( is only found in animals)vMembrane lipids are a
6、mphipathic.vThere are three major classes of lipids:Figure 10-2. The parts of a phospholipid molecule. Phosphatidylcholine, represented schematically (A), in formula (B), as a space-filling model (C), and as a symbol (D). The kink due to the cis-double bond is exaggerated in these drawings for empha
7、sis. Figure 10-3. A lipid micelle and a lipid bilayer seen in cross-section. Lipid molecules form such structures spontaneously in water. The shape of the lipid molecule determines which of these structures is formed. Wedge-shaped lipid molecules (above) form micelles, whereas cylinder-shaped phospholipid molecules (below) form bilayers.
