电压门控离子通道:铰链维胞失水 charged ions channel tectorial membrane closed channel orting ce filament stereocilia MA basilar membrane auditory nerve fibers BUNDLE NOT BUNDLE TILTED TILTED 应力激活的离子通道:2X1013N,004a
电压门控离子通道：铰链细胞失水 应力激活的离子通道：2X1013N，0.04nm
3. Active transport: Carrier protein mediated movement up the gradient A. This process differs from facilitated diffusion in two crucial aspects s Active transport maintains the gradients for potassium sodium calcium. and other ions across the cell membrane Always moves solutes up a concentration or electrochemical gradient Active transport couples the movement of substances against gradients to ATP hydrolysis. i.e Always requires the input of energy
3. Active transport: Carrier proteinmediated movement up the gradient A. This process differs from facilitated diffusion in two crucial aspects: ❖Active transport maintains the gradients for potassium, sodium, calcium, and other ions across the cell membrane. Always moves solutes up a concentration or electrochemical gradient; ❖Active transport couples the movement of substances against gradients to ATP hydrolysis. i.e Always requires the input of energy
B. Cells carry out active transport in three main ways LIGHT electrochemical gradient TP ADP +P COUPLED ATP-DRIVEN LIGHT-DRIVEN TRANSPORTER PUMP PUMP 8 Couple the uphill transport of one solute across membrane to the downhill transport of another. ouple uphill transport to the hydrolysis ofATP. .o Mainly in bacteria, couple uphill transport to an input of energy from light
B. Cells carry out active transport in three main ways ❖ Couple the uphill transport of one solute across membrane to the downhill transport of another. ❖ Couple uphill transport to the hydrolysis of ATP. ❖ Mainly in bacteria, couple uphill transport to an input of energy from light
C Direct active transport depends on four types of transport ATPases Exterior T T Cytosol r E ATP-binding region ATP-binding region P-class pump Fand V-class pump ABC superfamily The four classes ofATP-powered transport proteins P" type stands for phosphorylation ABC(ATP-binding Cassette)superfamily, bacteria--humans Two transmembrane(t) domains and two cytosolic ATP-binding(a)domains
C. Direct active transport depends on four types of transport ATPases The four classes of ATP-powered transport proteins: “P” type stands for phosphorylation; ABC (ATP-binding Cassette) superfamily, bacteria—humans. Two transmembrane (T) domains and two cytosolic ATP-binding (A) domains
今 The na+-K+ ATPase A coupling active transport to ATP hydrolysis. OUTSIDE >The Na*-Kt ATPase requires Kt outside. Nat and ATP inside, and is inhibited by ouabain OF CELL >The ratio of Na: K pumped Figure 8-10 The Na /K Pump. The Nat/ K pump found in mast animal calis consists of two c and twa B souns. The a subunits are 3: 2 for each ATP hydrolvzed transmembrane pens, with binding sites for AlP en the cytoplasmic side. The B subunits are located on the outer side of the membrane and are ghcosvlatsd. The pump is shown in the E, conformation, which is open ta the inside f Ue cell Binding of sodium ions causas a >The Na*-K+ ATPase is a P-type coformational change to the E, tarm, what opens to the outside pump. This ATPase seruentially phosphorylates and dephosphory- 器 K -and ouabain. lates itself during the pumping cycl electrochemical >The Nat-K ATPase is found CYTOSOL la· binding only in aniimals ADP-P 2
❖The Na+ -K+ ATPase ---A coupling active transport to ATP hydrolysis. ➢The Na+ -K+ATPase requires K+ outside, Na+ and ATP inside, and is inhibited by ouabain. ➢The ratio of Na+ :K+ pumped is 3:2 for each ATP hydrolyzed. ➢The Na+ -K+ATPase is a P-type pump.This ATPase seruentially phosphorylates and dephosphorylatesitself during the pumping cycle. ➢The Na+ -K+ATPase is found only in aniimals