3.2 Flashcards
Secondary active transport
-goes against the gradient
-driven by cotransport with an ion moving with its gradient
-has 2 transporters
Primary active transport
-goes against the gradient
-is driven by ATP hydrolysis
Uniporters
Carries 1 substrate
Cotransporters
-couple transport of 2 substrates together
Symporters
Carries 2 substrates in the SAME direction
Antiporters
Carries 1 substrate in 1 direction and the other in the OPPOSITE direcction
GLUT1
-transports D-glucose into erythrocytes with the gradient
-uniporter
-integral membrane protein
-changes conformation–>T1 = D-glucose binding site on outside
T2 = binding site on cytoplasm/inside
4 steps of D-glucose transport
- D-glucose binds to T1 sute of GLUT1
- Intermolecular interactions T1 into T2 which causes transit of D-glucose through the bilayer
- D-glucose is released from T2 GLUT1 into cytoplasm
- GLUT1 turns back into T1
NO ATP IS REQUIRED TO CHANGE CONFORMATION
4 hallmarks of passive transport
- Greatly increases diffusion rate
- Transports with concentration gradient
- Saturability
- Specificity
what kind of transport is GLUT1
Uniporter
What kind of transport is Lactose permease
-Symporter
-Imports lactose against gradient = Secondary active transport
What kind of transport is chloride-bicarbonate exchanger
-Antiporter
-bicarbonate goes in and out of erythrocyte with Cl- ion
-bicarbonate goes 1 direction and Cl- goes the opp direction
What kind of transport is SERCA, Na+ K+ pump
P-type ATPase active transport
What kind of transporter is CFTR
ABC-type ATPase active transporter
What does transporter 1 and 2 do in lactose permease
-Transporter 1: Uses ATP to establish gradient
-Transporter 2: Uses energy of H+ to transport lactose against gradient
-Secondary transporter relies on energy used by primary transporter
