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AP Bio Chapter 36
Word | Definition |
---|---|
transport proteins | embedded in cell membranes, allows most solutes to pass quickly |
selective channels | selective passageways across the membrane |
proton pump | important active transporter which hydrolyzes ATP and uses the released energy to pump hydrogen ions out of the cell generating membrane potential |
cotransport | the coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient |
chemiosmosis | the production of ATP using the energy of hydrogen ion gradients across a membrane to phosphorlate ADP, powers ATP synthesis in most cells |
osmosis | the passive transport of water across a membrane |
water potential | combination of solute concentration and pressure |
megapascals (MPa) | unit for water potential |
tension | negative pressure on water or solutions |
plasmolyze | shrink or pull away from cell wall |
turgor pressure | the cell begins to swell and push against cell wall |
turgid | the pressure that keeps it firm |
aquaporin | water specific transport proteins, do not actively transport water, facilitate water diffusion across a lipid bi-layer |
tonoplast | regulates molecular traffic between the cytosol land vacuolar contents |
symplast | cytoplasmic continuum connected by the plasmodemata between cells |
apoplast | a compartment in the continuum of cell walls |
bulk flow | the movement of fluid driven by pressure |
mycorrhizae | "infected" roots, the term for the symbiotic structures consisting of the plant's roots intermingled with with hyphae (filaments) |
endodermis | the innermost layer of cells in the root cortex, surrounds the stele and functions as the checkpoint for the selective passage of minerals from the cortex into the vascular cylinder |
Casparian Strip | a belt made of suberin, a waxy material that is impervious to water and dissolved minerals |
root pressure | the upward push of xylem sap |
guttation | caused by root pressure, the exudation of water droplets that can be seen in the morning on the tips of grass blades or on the leaf margins of some herbaceous dicots |
transpiration to photosynthesis ratio | the amount of water lost per gram of CO2 assimilated into organic material by photosynthesis |
circadian rhythms | cycles that have intervals of approximately 24 hrs |
transloctaion | the transport of food in the plant |
a sugar source | a plant organ in which sugar is being produced by either photosynthesis or the break down of starch |
sugar sink | an organ that consumes or stores sugar |
transfer cells | modified cells to enhance the transfer of solutes between apoplast and symplast |