The channel proteins. in contrast, interact with the solute to be transported much more weakl The channel proteins facilitate diffusion by forming ydrophilic transmembrane channels x Transport through channel proteins occurs at a much faster rate than transport mediated by carrier proteins
vThe channel proteins,in contrast, interact with the solute to be transported much more weakly. The channel proteins facilitate diffusion by forming hydrophilic transmembrane channels vTransport through channel proteins occurs at a much faster rate than transport mediated by carrier proteins
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 e Always requires the input of energy
3. Active transport: Carrier protein- mediated movement up the gradient A. This process differs from facilitated diffusion in two crucial aspects: vActive transport maintains the gradients for potassium, sodium, calcium, and other ions across the cell membrane. Always moves solutes up a concentration or electrochemical gradient; vActive 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 ATP ADP+P COUPLED ATP-DRIVEN LIGHT-DRIVEN TRANSPORTER PUMP PUMP .o Couple the uphill transport of one solute across membrane to the downhill transport of another. .o Couple uphill transport to the hydrolysis of ATP Mainly in bacteria, couple uphill transport to an input of energy from light
B. Cells carry out active transport in three main ways v Couple the uphill transport of one solute across membrane to the downhill transport of another. v Couple uphill transport to the hydrolysis of ATP v Mainly in bacteria, couple uphill transport to an input of energy from light
C. Direct active transport depends on four types of transport ATPases Exoplasmic CIcc 4H- Cytosolic A ATP ADP rB/a BF B/A BVV,ATP ADP +P ADP+Pi ATP ATP ADP +P class F-class V-class ABC-class The four classes ofATP-powered transport proteins: “P” type stands for phosphorylation; ABC (ATP-binding Cassette)supe milv, 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
P class: become phosphorylated as part of the transport cycle F class: synthesize ATP by movement of H down an electrochemical gradient V class: hydrolyze ATP to pump H* from cytosol to organelle for acidification ABC claSs couple atP hydrolysis to solute movement