文档介绍：Chapter 4: Cell Membrane and Cell Surface
I. Cell Membrane
II. Cell Junctions
III. Cell Adhesion
IV. Extracellular Matrix
.cn/chinese/documents/chenjg/
I. Biomembranes: Their Structure, Chemistry and Functions
Learning objectives:
A brief history of studies on the structrure of the plasma membrane
Model of membrane structure: an experimental perspective
The position of membranes
Characteristics of biomembrane
An overview of the functions of biomembranes
1. A brief history of studies
on the structrure of the
plasmic membrane
A. Conception:
Plasma membrane(cell membrane),
Intracellular membrane,
Biomembrane.
B. The history of study
Overton(1890s):
Lipid nature of PM;
(1959):
The TEM showing:the trilaminar appearance of PM;
Unit membrane model;
and (1972):
fluid-mosaic model;
et al(1997):
lipid rafts model;
Functional rafts in Cell
membranes.
Nature 387:569-572
2. Singer and Nicolson’s Model of membrane structure: The fluid-mosaic model is the “central dogma” of membrane biology.
The core lipid bilayer exists in a fluid state, capable of dynamic movement.
Membrane proteins form a mosaic of particles rating the lipid to varying degrees.
The Fluid Mosaic Model, proposed in 1972 by Singer and Nicolson, had two key features, both implied in its name.
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 emphasis.
3. The position of membranes
A. Membrane Lipids: The Fluid Part of the Model
Phospholipids:
Phosphoglyceride and sphingolipids
Glycolipids
Sterols ( is only found in animals)
Membrane lipids are amphipathic.
There are three major classes of lipids:
Figure 10-3. A lipid micelle and a lipid bilayer seen in cross-section. Lipid molecules form such structures spontaneously in water. The shape