BI111 Lecture Notes - Lecture 19: Water Potential, Electrochemical Gradient, Passive Transport
Document Summary
Simple difusion is simplest form of passive transport: requires no metabolic energy, substances moves down concentraion or electrochemical gradient. How eicient: not over long distances, 10 um in 0. 1 sec, 100 um in 1 sec, 1 mm in 100 secs. Acive transport requires metabolic energy: based on h+ pumps, h+ gradient maintained through atp use, h+ difusion into cell powers uptake of solutes. Symport: material transported in same direcion as movement of h+ and solute, organic uptake. Aniport: material transported in opposite direcion to movement of h+ and solute, na export. Difusion: the spontaneous movement of molecules of paricles along the concentraion gradient. Water molecules difuse across a selecively permeable membrane from an area of higher water concentraion to a lower water concentraion. Hypertonic: higher concentraion of solutes outside the cell, cell shrinks. Isotonic: equal concentraion solutes inside and outside the cell. Hypotonic: lower concentraion of solutes outside the cell.