Transcript Transport of Ion & Small Molecules Across Cell Membranes

Transport of Ion & Small
Molecules Across Cell
Membranes
Mina Pakzad
ATP powered pump: Pumps utilize the energy released by ATP hydrolysis to power movement of
specific ion against its concentration gradient.
Ion channels: They move ions down their concentration gradient.
Transporters:
another
Uniporters- moves one ion down the concentration gradient
Symporter, Antiporter_ AKA cotransporter, they couple the
movement of one type of ion against concentration gradient with movement of
down its concentration gradient.
Model of uniport transport by GLUT 1
1. Glucose binds to the outward-facing site.
2. Conformational change results in binding site’s facing
inward towards the cytosol.
3. Glucose releases in the cell.
4. Reverse conformational change.
Operational model of the calcium ATPase in the SR
membrane of skeletal muscle cells
Operational model of the Na/K ATPase in the
plasma membrane