第五章物质的跨膜榆 马信号传递 第一节物质的跨膜运输
第五章 物质的跨膜运输 与信号传递 第一节 物质的跨膜运输
Plasma Membrane lic portions of the re exposed to water Outside cell Proteins can move de of the membrane laterally through the Carbohydrate phospholipid bilayer. side chains hyd rophobic portions in the hydrophobic core me proteins receive channels through which of the membrane signals from the ions and molecules can enter and leave the cel outside the cell 0 and pass them on to the inside of the cell phospholipid while others extend Inside cell only part way into the bilayer
Plasma Membrane
被动运输 ■被动运输( passive transport)是指通 过简单扩散或协助(osue lipid-soluble molecules, 扩散实现物质由高 O2, CO2, H2O 浓度到低浓度方向 的跨膜转运。 (一)简单扩散 (inside)
一、被动运输 ◼ 被动运输（passive transport）是指通 过简单扩散或协助 扩散实现物质由高 浓度到低浓度方向 的跨膜转运。 ◼ （一）简单扩散
18 Water HO co N Small uncharged wrea polar Ethanol molccules Largest uncharged polar Glucose molecules K- M9+ Ca21: lons CHCO HPOs Charged Amino acids golar ATP molecules Glucose Bphasphate
(二)协助扩散 在协助扩散中,特异的膜蛋白“协助”物质转运使 其转运速率增加,转运特异性增强。 Transported Uniport molecules Carrier / Channel○ molecule Simple diffusion Facilitated diffusion Passive transport
（二）协助扩散 在协助扩散中，特异的膜蛋白“协助”物质转运使 其转运速率增加，转运特异性增强