| A | B |
|---|
| active transport | movement of a substance across a biological membrane against its concentration with the help of energy input and specific transport proteins |
| apoplast | continuum of cell walls plus the extracellular spaces |
| aquaporin | transport protein in the plasma membrane that specifically facilitates the diffusion of water across the membrane |
| bulk flow | movement of water due to a difference in pressure between two locations |
| Casparian strip | water-impermeable ring of wax in the endodermal cells of plants that blocks the passive flow of water and solutes into the stele by way of cell |
| chemiosmosis | energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work |
| circadian rhythm | physiological cycle of about 24 hours |
| cotransport | coupling of the downhilldiffusion of one substance to the uphilltransport of another |
| endodermis | cylinder one cell thick that forms the boundary between the cortex and the vascular cylinder |
| flaccid | cell is limp in surroundings where there is no tendency for water to enter |
| guttation | exudation of water droplets caused by root pressure in certain plants |
| megapascal (MPa) | unit of pressure equivalent to 10 atmospheres of pressure |
| membrane potential | charge difference between a cell’s cytoplasm and the extracellular fluid due to the differential distribution of ions |
| mycorrhizae | mutualistic associations of plant roots and fungi |
| osmosis | diffusion of water across a selectively permeable membrane |
| osmotic potential | measures the effect of solutes on the direction of water movement it is proportional to the number of dissolved solute molecules in a solution |
| plasmolyze | protoplast pulls away from the cell wall as a result of water loss |
| pressure potential | consists of the physical pressure on a solution which can be positive zero or negative |
| proton pump | uses ATP to force hydrogen ions out of a cell generating a membrane potential in the process |
| root pressure | upward push of xylem sap in the vascular tissue of roots |
| solute potential | measures the effect of solutes on the direction of water movement is proportional to the number of dissolved solute molecules in a solution |
| sugar sink | organ that is a net consumer or storer of sugar |
| sugar source | organ in which sugar is being produced by either photosynthesis or the breakdown of starch |
| symplast | continuum of cytoplasm connected by plasmodesmata between cells |
| tonoplast | membrane that encloses the central vacuole in a plant cell separating the cytosol from the vacuolar contents |
| transfer cell | cell with numerous ingrowths of its wall increasing surface area enhancing the transfer of solutes between apoplast and symplast |
| translocation | movement of organic nutrients in the phloem of vascular plants |
| transpiration | evaporative loss of water from a plant |
| transport protein | protein helps a substance or class of substances to cross the membrane |
| turgid | cell become turgid if it has a greater solute concentration than its surroundings resulting in entry of water |
| turgor pressure | force directed against a cell wall after the influx of water |
| vacuolar membrane | encloses the central vacuole in a plant cell |
| water potential | physical property predicting the direction in which water will flow governed by solute concentration and applied pressure |
| wilting | drooping of leaves and stems as a result of plant cells becoming flaccid |
| xerophyte | plant adapted to an arid climate |
