( Boundary and permeability barrier ② Organization and localization of function Nucleus 人 D Cell-to-cell communication (Transport processes ● Nutrients ④ Signal detection
av4 I 5a3 Iigure 430 The plasma membrane ef the human crythroote li Sanmin trophonsis(SDs- PAGE) used to fractionate the protrins of the erythmcyte sk of the gel. The ge has ben stained DorI 和出 Vard RckanlF Aka, a Hare wra cen B eL 4391. 1971: k ceney R加为都知k
Hypotonic medium xidase 一7 Figure 7-24 A Method For Labeling Proteins Exposed on One or oth Surfaces of a Membrane Vesicle. (a)When lactoperoxidase (LP) and 125) are present in the solution outside a membrane vesicle, LP catalyzes the labeling of membrane proteins exposed on the outer membrane surface (i.e. proteins A and B). If membrane vesicles are (b) first incubated in a hypotonic medium to make them permeable to LP and (c) then transferred to an isotonic solution containing 12I but no external LP proteins exposed on the inner membrane surface(i.e proteins B and C)become labeled
1) glycocalyx糖萼 (1)糖萼由细胞包被( cell coat- carbohydrate portions of membrane glycoproteins and glycolipids)和细胞外表面粘 附物质( extracellular surface adherent materials- proteoglycans, and a variety of glycoproteins)组成。前者 是指质膜糖蛋白或糖脂伸向胞外部分的糖链部分,虽然它们 是质膜的一个结构部分,但是它们在细胞外侧并且能够用糖 苷酶等将其移去而不使质膜或细胞受到致命性的损伤。后者 是处于包被外而又与包被紧密粘附的胞外基质(主要包括蛋 白多糖、糖蛋白等),实际上这两层结构界限不清,用钌红 染色时,染成一片,不易分辨开,因此细胞膜外缘的两层复 合物整体上称为糖萼( glycocalyx) (2)glycocalyx functions glycocalyx is thought to mediate cell-cell and cell- substratum interactions, provide mechanical protection to cells, and as a barrier to particles moving toward the plasma membrane
1) glycocalyx 糖萼 (1) 糖萼由细胞包被(cell coat – carbohydrate portions of membrane glycoproteins and glycolipids) 和细胞外表面粘 附 物 质 (extracellular surface adherent materials-- proteoglycans, and a variety of glycoproteins) 组成。前者 是指质膜糖蛋白或糖脂伸向胞外部分的糖链部分，虽然它们 是质膜的一个结构部分，但是它们在细胞外侧并且能够用糖 苷酶等将其移去而不使质膜或细胞受到致命性的损伤。后者 是处于包被外而又与包被紧密粘附的胞外基质（主要包括蛋 白多糖、糖蛋白等），实际上这两层结构界限不清，用钌红 染色时，染成一片，不易分辨开，因此细胞膜外缘的两层复 合物整体上称为糖萼(glycocalyx)。 (2) glycocalyx functions glycocalyx is thought to mediate cell-cell and cellsubstratum interactions,provide mechanical protection to cells, and as a barrier to particles moving toward the plasma membrane
J 糖被