BI111 Lecture Notes - Phloem, Guttation, Desiccation
Document Summary
Simple diffusion is simplest form of passive transport. 10 m in 0. 1 sec; 100 m in1 sec; 1 mm in 100 sec. H+ diffusion into cell powers uptake of solutes. Material transported in same direction as movement of h+ and solute, organic uptake. Material transported in opposite direction to movement of h+ and solute, na+ export. Diffusion: the spontaneous movement of molecules or particle along a concentration gradient. Water molecules diffuse across a selectively permeable membrane to an area of higher water concentration 9low solute concentration), to a lower water concentration (high solute concentration). Hypertonic: higher concentration of solutes outside of the cell. Isotonic: equal concentration of solute inside and outside of the cell. Hypotonice: lower concentration of solutes outside of the cell. Water potential of pure water: =0 in open container under normal atmospheric pressure & temperature. Causes water to move across permeable membrane (into cell) from region of high water potential to low.
