click below
click below
Normal Size Small Size show me how
Biotest 10/13
Transpiration
Side 1 | Side 2 |
---|---|
Passive Transport | Tendency for solutes to diffuse down their gradients across a membrane without metabolic energy |
Active Transport | pumping of solutes across membranes against their electrochemical gradient, expends energy |
Transport Proteins | proteins that bind selectively to a solute on one side of the membrane and release it on the other side |
Proton Pump | active transport protein, uses ATP to pump H+ ions out of the cell |
Membrane Potential | Separation of opposite charges across a membrane. |
Cotransport | Transport protein couples downhill passage of H+ and the uphill passage of another solute (NO3) |
Chemiosmosis | Movement of ions across a semi-permeable membrane down a concentration gradient |
Osmosis | passive transport of water across a membrane |
Water potential | The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure. |
Megapascal (MPa) | A unit of pressure equivalent to 10 atmospheres of pressure. |
Solute/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; can be either zero or negative. |
pressure potential | A component of water potential that consists of the physical pressure on a solution, which can be positive, zero, or negative. |
Tugor Pressure | The force directed against a cell wall after the influx of water and the swelling of a walled cell due to osmosis. |
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. |
Turgid | Very firm. A walled cell becomes turgid if it has a greater solute concentration than its surroundings, resulting in entry of water. |
Flaccid | Limp. A walled cell is flaccid in surroundings where there is no tendency for water to enter. |
Wilting | The drooping of leaves and stems as a result of plant cells becoming flaccid. |
Aquaporins | A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis). |
Vacuolar Membrane/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 tonoplast. |
Symplast | In plants, the continuum of cytoplasm connected by plasmodesmata between cells. |
Apoplast | In plants, the continuum of cell walls plus the extracellular spaces. |
Plasmodesma | Connects cytosolic compartments of neighboring cells |
3 Compartments of plant cells | cell wall, cytosol, vacuole |
Transmembrane Route | Out of one cell, across cell wall, into another cell; repeated crossings of plasma membranes |
Symplastic Route | moves from cell to cell via plasmodesma; only has to pass through the first plasma membrane |
Apoplastic Route | short distance transport along the continuum of cell walls |
Bulk Flow | The movement of water due to a difference in pressure between two locations. (through xylem/phloem) |
Root Hairs | extension of the epidermis, bulk of surface area, dirt adhere's tightly |
Mycorrhizae | Mutualistic associations of plant roots and fungi. Helps absorb water/minerals |
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. |
Casparian strip | Water–impermeable ring of wax in the endodermal cells that blocks passive flow of water and solutes by way of cell walls. ensures that no minerals can reach the vascular tissue of the root without crossing a selectively permeable plasma membrane |
Transpiration | The evaporative loss of water from a plant. |
Root Pressure | The upward push of xylem sap in the vascular tissue of roots. |
Pushing Xylem Sap | Root Pressure: minerals accumulate lowering Water Potential, water flows in generating root pressure that pushes xylem sap upwards |
Guttation | exudation of water droplets |
Pulling Xylem Sap | The Transpiration–Cohesion–Tension Mechanism |
Stomata becoming Turgid | uptake of potassium ions by change in membrane potential from sending H+ ions out |
Stomata cues | Light stimulates accumulation of K+, blue light triggers activity of ATP. Depletion of CO2. Guard cells internal clock |
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. |
Xerophyte | A plant adapted to an arid climate. Thick cuticle, reduce respiration |
translocation | transport of organic nutrients in the plant |
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. |
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. |
Pressure Flow in Phloem | Phloem sap moves from source to sink down sieve tubes by positive pressure |
Hormones | In multicellular organisms, one of many types of circulating chemical signals that are formed in specialized cells, travel in body fluids, and act on specific target cells to change their functioning. |
Tropism | A growth response that results in the curvature of whole plant organs toward or away from stimuli owing to differential rates of cell elongation. |
Phototropism | Growth of a plant shoot toward or away from light. |
Auxin | A term that primarily refers to indoleacetic acid (IAA), a natural plant hormone that has a variety of effects, including cell elongation, root formation, secondary growth, and fruit growth, herbicide. |
expansins | Plant enzymes that break the cross–links (hydrogen bonds) between cellulose microfibrils and other cell wall constituents, loosening the wall′s fabric. |
Cytokinis | A class of related plant hormones that retard aging and act in concert with auxin to stimulate cell division, influence the pathway of differentiation, and control apical dominance, slow deterioration |
Gibberellins | A class of related plant hormones that stimulate growth in the stem and leaves, trigger the germination of seeds and breaking of bud dormancy, and stimulate fruit development with auxin. |
Brassinosteroids | Steroid hormones in plants that have a variety of effects, including cell elongation, retarding leaf abscission, and promoting xylem differentiation. |
Abscisic Acid | A plant hormone that slows down growth, often antagonizing actions of growth hormones. Two of its many effects are to promote seed dormancy and facilitate drought tolerance. |
Ethylene | The only gaseous plant hormone. Among its many effects are response to mechanical stress, programmed cell death, leaf abscission, and fruit ripening. |
Triple Response | A plant growth maneuver in response to mechanical stress, involving slowing of stem elongation, a thickening of the stem, and a curvature that causes the stem to start growing horizontally. |
Apoptosis | The changes that occur within a cell as it undergoes programmed cell death, which is brought about by signals that trigger the activation of a cascade of suicide proteins in the cell destined to die |
photomorphogenesis | Effects of light on plant morphology. |
action spectrum | A graph that depicts the relative effectiveness of different wavelengths of radiation in driving a particular process |
blue–light photoreceptors | A class of light receptors in plants. Blue light initiates a variety of responses, such as phototropism, slowing of hypocotyl elongation, stomata opening |
phytochromes | A class of light receptors in plants. Mostly absorbing red light, these photoreceptors regulate many plant responses, including seed germination and shade avoidance. |
Photoperiodism | A physiological response to photoperiod, the relative lengths of night and day. An example of photoperiodism is flowering. |
short–day plant | A plant that flowers (usually in late summer, fall, or winter) only when the light period is shorter than a critical length. |
long–day plant | A plant that flowers (usually in late spring or early summer) only when the light period is longer than a critical length. |
day–neutral plant | A plant whose flowering is not affected by photoperiod. |
vernalization | The use of cold treatment to induce a plant to flower. |
florigen | A flowering signal, not yet chemically identified, that may be a hormone or may be a change in relative concentrations of multiple hormones. |
gravitropism | A response of a plant or animal to gravity. |
statolith | a specialized plastid that contains dense starch grains and may play a role in detecting gravity. |
thigmomorphogenesis | A response in plants to chronic mechanical stimulation, resulting from increased ethylene production. An example is thickening stems in response to strong winds. |
thigmotropism | A directional growth of a plant in response to touch. |
action potential | A rapid change in the membrane potential of an excitable cell, caused by stimulus–triggered, selective opening and closing of voltage–sensitive gates in sodium and potassium ion channels. |
heat–shock protein | A protein that helps protect other proteins during heat stress. Heat–shock proteins are found in plants, animals, and microorganisms. |
jasmonic acid | An important molecule in plant defense against herbivores. |
virulent | A term describing a pathogen against which a plant has little specific defense. |
gene–for–gene recognition | A widespread form of plant disease resistance involving recognition of pathogen–derived molecules by the protein products of specific plant disease resistance genes. |
phytoalexin | An antibiotic, produced by plants, that destroys microorganisms or inhibits their growth. |
salicylic acid | A plant hormone that may be partially responsible for activating systemic acquired resistance to pathogens. |