Chap 36 Transport in Vascular Plants Flashcards
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| 411095186 | active transport | The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins | |
| 411095187 | apoplast | In plants, the continuum of cell walls plus the extracellular spaces | |
| 411095188 | aquaporin | A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis). | |
| 411095189 | bulk flow | The movement of water due to a difference in pressure between two locations | |
| 411095190 | Casparian strip | A 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 walls | |
| 411095191 | chemiosmosis | An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Most ATP synthesis in cells occurs by chemiosmosis | |
| 411095192 | circadian rhythm | A physiological cycle of about 24 hours that is present in all eukaryotic organisms and that persists even in the absence of external cues | |
| 411095193 | cotransport | The coupling of the downhilldiffusion of one substance to the uphilltransport of another against its own concentration gradient. | |
| 411095194 | endodermis | The innermost layer of the cortex in plant roots; a cylinder one cell thick that forms the boundary between the cortex and the vascular cylinder. | |
| 411095195 | flaccid | Limp. A walled cell is flaccid in surroundings where there is no tendency for water to enter | |
| 411095196 | guttation | The exudation of water droplets, caused by root pressure in certain plants | |
| 411095197 | megapascal (MPa) | A unit of pressure equivalent to 10 atmospheres of pressure | |
| 411095198 | membrane potential | The charge difference between a cell's cytoplasm and the extracellular fluid, due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances | |
| 411095199 | mycorrhizae | Mutualistic associations of plant roots and fungi | |
| 411095200 | osmosis | The diffusion of water across a selectively permeable membrane | |
| 411095201 | osmotic potential | A component of water potential that is proportional to the number of dissolved solute molecules in a solution and measures the effect of solutes on the direction of water movement; also called solute potential, it can be either zero or negative. | |
| 411095202 | plasmolyze | To shrink and pull away from a cell wall, or when a plant cell protoplast pulls away from the cell wall as a result of water loss. | |
| 411095203 | pressure potential (??????p) | A component of water potential that consists of the physical pressure on a solution, which can be positive, zero, or negative | |
| 411095204 | proton pump | An active transport mechanism in cell membranes that uses ATP to force hydrogen ions out of a cell, generating a membrane potential in the process. | |
| 411095205 | root pressure | The upward push of xylem sap in the vascular tissue of roots. | |
| 411095206 | solute potential (??????s) | A component of water potential that is proportional to the number of dissolved solute molecules in a solution and measures the effect of solutes on the direction of water movement; also called osmotic potential, it can be either zero or negative. | |
| 411095207 | sugar sink | A plant organ that is a net consumer or storer of sugar. Growing roots, shoot tips, stems, and fruits are sugar sinks supplied by phloem | |
| 411095208 | sugar source | A plant organ in which sugar is being produced by either photosynthesis or the breakdown of starch. Mature leaves are the primary sugar sources of plants. | |
| 411095209 | symplast | In plants, the continuum of cytoplasm connected by plasmodesmata between cells | |
| 411095210 | tonoplast | A membrane that encloses the central vacuole in a plant cell, separating the cytosol from the vacuolar contents, called cell sap; also known as the vacuolar membrane. | |
| 411095211 | transfer cell | A companion cell with numerous ingrowths of its wall, increasing the cell's surface area and enhancing the transfer of solutes between apoplast and symplast | |
| 411095212 | translocation | (1) An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients in the phloem of vascular plants. | |
| 411095213 | transpiration | The evaporative loss of water from a plant. | |
| 411095214 | transport protein | A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane | |
| 411095215 | turgid | Very firm. A walled cell become turgid if it has a greater solute concentration than its surroundings, resulting in entry of water. | |
| 411095216 | turgor pressure | The force directed against a cell wall after the influx of water and the swelling of a walled cell due to osmosis | |
| 411095217 | vacuolar membrane | A membrane that encloses the central vacuole in a plant cell, separating the cytosal from the vacuolar contents, called cell sap; also known as the tonoplast | |
| 411095218 | water potential | The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure | |
| 411095219 | wilting | The drooping of leaves and stems as a result of plant cells becoming flaccid. | |
| 411095220 | xerophyte | A plant adapted to an arid climate |