BIOL 2010 Lecture Notes - Lecture 8: Potential Gradient, Water Vapor, Manganese
Document Summary
Water and its movement through the plant. Transport of food substances (organic solutes) in solution. Large molecules move more slowly than small molecules. Solvent - liquid in which substances dissolve. Semipermeable membranes - membranes in which different substances diffuse at different rates. Osmosis - diffusion of water through a semipermeable membrane from a region where water is more concentrated to a region where it is less concentrated. Osmosis is a particular type of diffusion for water molecules. Osmosis stops if the concentration of water on both sides of he membrane becomes equal. Osmotic pressure - pressure required to prevent osmosis: osmotic potential balanced by resistance of cell wall. Pressure potential (turgor pressure) - pressure that develops against walls as result of water entering cell. Turgid cell firm cell due to water gained by osmosis: water potential of cell = osmotic pressure + pressure potential. Water moves from cell with higher water potential to cell with lower water potential.