ANSC 3301 Lecture Notes - Lecture 3: Active Transport, Atp Synthase, Electrochemical Gradient
Document Summary
Uses atp to move protons through the f- pore. Works as atp synthase in mitochondria and chloroplast. Mdr (multidrug resistance) transport protein- transports many different drugs out of tumor cells. Will kick drugs out of cells, such as with cancer patients. Cftr- cystic fibrosis transmembrane conductance regulator (the mutated protein in cystic fibrosis) Uses the energy from a steep concentration gradient, like the na gradient established across cell membrane by the na-k atpase, to transport other molecules against their concentration gradient. Cotransporters (symporters) move molecules in the same direction. Countertransporters (antiporters or exchangers) move molecules in opposite directions. Sometimes, primary and secondary active transporters are coupled. Ex: a proton pump uses atp to pump protons to the extracellular side, establishing a proton gradient across the cell membrane. Electroneutral carriers: transport uncharged molecules or exchange an equal number of charged particles. Proton pump in stomach (no net charge movement) Electrogenic carriers: transfer a charge, eg. na+/k+atpase exchanges 3na+ for 2k+
