BI111 Lecture Notes - Casparian Strip, Water Potential, Turgor Pressure
Document Summary
Membrane potential: an electrical voltage that measures the potential inside a cell membrane relative to the fluid just outside; it is negative under resting conditions and is positive during an action potential. Water potential: the potential energy of water, representing the difference in free energy between pure water and water in cells an solutions; it is the driving force for osmosis. Solute potential: the effect of dissolved solutes on water potential. Osmosis: the passive transport of water across a selectively permeable membrane in response to solute concentration or pressure gradients. Tonoplast: the membrane that surround the central vacuole in a plant cell. Guttation: the exudation of water from leaves as a result of strong root pressure. Translocation: the long distance transport of substances by xylem and phloem. Passive transport: substances move with their concentration gradient the cells do not need to expend energy. (simple and facilitated diffusion)
