| A | B |
|---|
| ABC Transporters have two | transport domains, two cytosolic ATP binding domains |
| MDR Transporters | Multidrug-resistance pumps and MDR pumps “send” noxious molecules out of cell |
| Flippase Model of Activity of ABC Transporters | Facilitates movement of lipid from one leaflet to another |
| The membrane resting potential of most animal cells is mediated by movement | of K+ ions down their concentration gradient—out of the cell. |
| The movement of an ion across a membrane is governed by both the | concentration gradient of the ion and electrical potential |
| Chemical free energy change with movement of ion | ΔGC = RT ln[ioninside]/[ionoutside] |
| Electrical free energy change | ΔGE = FE (for resting cells ~-70 mV) |
| Antiporters and Symporters—Cotransporters | Use the movement of a molecule (Na+ or H+) |
| Antiporters and Symporters | movement is always coupled |
| Cotransporters Regulate | Cytosolic pH |
| Transepithelial Transport | Differential transport of molecules across polarized epithelial cells |
| Intestinal Epithelia | Aborption of nutrients and ions from intestinal contents at apical aspect |
