第一篇细胞生理学 第一章生物膜的物质转运功能 第二章细胞的兴奋 第三章细胞间信息传递 第四章肌细胞的收缩功能
第一篇 细胞生理学 第一章 生物膜的物质转运功能 第二章 细胞的兴奋 第三章 细胞间信息传递 第四章 肌细胞的收缩功能
第一章生物膜的物质转运功能 Chap 1 Cellular Membranes and Trans membrane Transport of Solutes and Water from Berne Levy Principles of Physiology (4thed)2005
第一章 生物膜的物质转运功能 from Berne & Levy Principles of Physiology (4th ed) 2005 Chap. 1 Cellular Membranes and Transmembrane Transport of Solutes and Water
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 of particular biochemical processes in specific organelles
• 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 of particular biochemical processes in specific organelles
Singer流动镶嵌模型 Outer face Phospholipid Fatty acyl Carbohydrate moiety heads(polar)o tails (nonpolar Cholesterol glycoprotein 00 Lipid bilayer ab000 Q Peripheral protein Integral proteins Peripheral protein Inner face ith covalent lipid anchor
Singer 流动镶嵌模型
Simple Diffusion SMALL CO2 HYDROPHOBIC MOLECULES N2 benzene SMALL H2O UNCHARGED POLAR glycerol ethanol MOLECULES LARGER amino acids UNCHARGED POLAR glucose nucleotides MOLECULES H+, Na HCO, K- IONS Ca CI Mg synthetic lipid bilayer
➢ Simple Diffusion
Specificity: only molecules with the requisite chemical structure are transported Saturation: as the concentration of the transported compound is increased, the rate of transport at first increases, but eventually a concentrations reached after which the transport rate increases no further. Competitive inhibition: structurally related molecules may compete for transport
• Saturation: as the concentration of the transported compound is increased, the rate of transport 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. • Competitive inhibition: structurally related molecules may compete for transport