北京大学：《分子细胞生物学》课程教学资源（PPT课件讲稿，英文版）Chapter 4 Cell Membrane and Cell Surface

Chapter 4: Cell Membrane and Cell Surface I. Cell membrane I. Cell Junctions II. Cell adhesion IV. Extracellular matrix http://www.cbi.pku.edu.cn/chinese/documents/chenjg

Chapter 4: Cell Membrane and Cell Surface I. Cell Membrane II. Cell Junctions III. Cell Adhesion IV. Extracellular Matrix http://www.cbi.pku.edu.cn/chinese/documents/chenjg/

(Boundary and permeability barrier (2 Organization and localization of function Nucler ⑤ Cell-to-cell communication Transport processes Nutrients (4) Signal deter

I Biomembranes: Their Structure Chemistry and functions Learning obiectives: a brief history of studies on the structrure of the plasma membrane 2. Model of membrane structure: an experimental perspective 3. The chemical composition of membranes 4. Characteristics of biomembrane 5. An overview of the functions of biomembranes

I. Biomembranes: Their Structure, Chemistry and Functions Learning objectives: 1. A brief history of studies on the structrure of the plasma membrane 2. Model of membrane structure: an experimental perspective 3. The chemical composition of membranes 4. Characteristics of biomembrane 5. An overview of the functions of biomembranes

1. 1. A brief history of studies on the structrure of the plasmic membrane 的 A. Conception: Plasma membrane(cell membrane), Intracellular membrane, Biomembrane B. The history of study ◇ Overton(1890s 200 Lipid nature of PM

1. 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;

◆ J.D. Robertson(1959) The TEM showing the trilaminar appearance of PM Unit membrane model: oS.J. Singer and GNicolson(1972) fluid-mosaic model ◆ K. Simons et a(1997) 办办的 lipid rafts model Functional rafts in Cell membranes Nature387:569-572 n4 Ahif hiskey af the sttu te ad t pena awarau MIA ler wwn se an)

 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 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. 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. (outside of cell) membrane protein The fluid mosaic glycoprotein Model, proposed in cholesterol 1972 by Singer and phospholipid Nicolson had two key features, both plasma membrane implied in its name. (cytoplasm inside of cell)

2. Singer and Nicolson’s 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 Mosaic Model, proposed in 1972 by Singer and Nicolson, had two key features, both implied in its name

3. The chemical composition of membranes A. Membrane Lipids: The Fluid Part of the model x Membrane lipids are amphipathic. .There are three major classes of lipids: Phospholipids: Phosphoglyceride and sphingolipids Glycolipids Sterols( is only found in animals)

3. The chemical composition 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:

CHOLINE polar hydrophilic) PHOSPHATE head group H head CH CH nonpolar CHs hydrophobic cis-double band 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 (). The kink due to the cis double bond is exaggerated in these drawings for emphasis

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

micelle water 0000000 balayer 0000000 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

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