生理学教学课件：第一章生物膜对物质的通透和转运

1、第一篇第一篇 细胞生理学细胞生理学 第一章第一章 生物膜对物质的通透和转运生物膜对物质的通透和转运 第二章第二章 细胞的兴奋细胞的兴奋 第三章第三章 细胞间信息传递细胞间信息传递 第四章第四章 肌细胞的收缩功能肌细胞的收缩功能 第一章第一章 生物膜对物质的通透和转运生物膜对物质的通透和转运 from Berne & Levy Principles of Physiology (4th ed) 2005 Chap. 1 Cellular Membranes and Trans-membrane Transport of Solutes and Water Singer-Nicolson的流动镶嵌

2、模型的流动镶嵌模型 Cell membrane serves as a permeability barrier that allows the cell to maintain a cytoplasmic composition far different from the composition of the extracellular fluid. The membranes that enclose the various organelles divide the cell into discrete compartments and allow the localization o

3、f particular biochemical processes in specific organelles. p 隔室化隔室化（compartmentalization） Simple Diffusion p 选择性地实现对物质的选择性地实现对物质的 通透通透（permeation） 和和转运转运 （transportation） via carriers Facilitated Diffusion Saturation: as the concentration of the transported compound is increased, the rate of transpo

4、rt at first increases, but eventually a concentrations reached after which the transport rate increases no further. Specificity: only molecules with the requisite chemical structure are transported. Competition: structurally related molecules may compete for transport. water channel ion channels叶公杼和

5、詹裕农叶公杼和詹裕农 Shaker钾通道钾通道 Ionic selectivity: 离子通道的随机活动离子通道的随机活动 Activation: voltage-gated, ligand-gated, mechanosensitive or background current channel primary active transport has a direct link to metabolic energy, via pumps. Active Transport secondary active transport derives energy from the concent

6、ration gradient of another substance that is actively transported, via symporter or antiporter (exchanger). 钠钾泵钠钾泵 细胞的钙转运系统细胞的钙转运系统 Endocytosis and Exocytosis receptor mediated endocytosis phagocytosis fluid phase endocytosis simple diffusion primary active transport endocytosis & exocytosis facilitated diffusion pores io