Na+-K+-ATP酶的作用原理 OUTSIDE Oligosaccharides OF CELL INSIDE Binding site OF CELL Na Na for ATP Na+ Figure 8-10 The Na/K+Pump.The Na+/K+pump found in most animal cells consists of two a and two B subunits.The o subunits are transmembrane proteins,with binding sites for ATP on the cytoplasmic side.The B subunits are located on the outer side of the membrane and are glycosylated.The pump is shown in the E conformation,which is open to the inside of the cell.Binding of sodium ions causes a conformational change to the E2 form,which opens to the outside
Na+ -K+ -ATP酶的作用原理
ADP ATP EXTRACELLULAR SPACE CYTOSOL phosphate in high-energy linkage
钠钾泵对维持渗透平的意义 low concentration high concentration of solute of solute outside cell inside cell WATER CELL MOVES BURSTS INTO CELL BY OSMOSIS, SWELLING osmotic pressure THE CELL H,c Figure 12-15 Osmosis.If the concentra- tion of solutes inside a cell is higher than that outside,water will move in by osmo- sis,causing the cell to swell.If the differ- ence in solute concentration is great enough,the cell will burst
钠钾泵对维持渗透平衡的意义
water discharging nucleus ions cell wall contractile vacuole vacuole A ANIMAL CELL (B) PLANT CELL (C PROTOZOAN Figure 12-16 Three ways in which cells avoid osmotic swelling.The animal cell keeps the intracellular solute concentra- tion low by pumping out ions (A).The plant cell is saved from swelling and burst- ing by its tough wall(B).The protozoan avoids swelling by periodically ejecting the water that moves into the cell(C)
2.协同主动运输（cotransport)) 动物细胞：Na+-葡萄糖运输，Na-氨基酸运输 ■植物细胞和细菌：H+.糖、H氨基酸的运输 方式 同向转运(symport)：物质运输方向与离子转移方向 相同 。反向转运（antiport):物质运输方向与离子转移方向 相反
2. 协同主动运输（cotransport) ◼ 动物细胞：Na+ - 葡萄糖运输，Na+ - 氨基酸运输 ◼ 植物细胞和细菌：H+ - 糖、 H+ -氨基酸的运输 ◼ 方式 ⚫ 同向转运（symport）：物质运输方向与离子转移方向 相同 ⚫ 反向转运（antiport）：物质运输方向与离子转移方向 相反