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33 Cards in this Set
- Front
- Back
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STEMS |
serve as conduits for water and nutrients, and supporting structures for leaves |
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Phyllotaxy |
The arrangement of leaves on a stem, specific to each species |
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Angle that allows leaf to get maximum sun exposure? |
137.5º |
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Taproot System |
One long, major root. Anchor plants, characteristic to MOST trees. |
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Transport in Vascular plants occurs on three scales: |
1. Transport of water and solutes by individual cells, such as root hairs. 2. Short distance transport of substances from cell to cell at the levels of tissues and organs. 3. Long distance transport within xylem and phloem of plant |
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Passive Transport |
diffuse down gradients across a membrane |
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Specific transport proteins enable certain solutes to cross a membrane |
DUH LEARN IT |
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Co-transport |
A transport protein couples the passage of one solute (downhill) to the passage of another (uphill) |
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Osmosis |
Balances water uptake and loss Osmosis determines the net uptake or water loss by a cell and is affected by solute concentration and pressure Water will normally move by osmosis from solution with lower solute to solution with higher solute Plants have a cell wall which adds another factor – physical pressure |
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Water potential |
Measures combined effects of solute concentration and water pressure. Determines movement of water. |
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Potential |
Water's capactiy to perform work when it moves from a region of higher concentration to lower concentration |
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Formula for water pressure
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Water potential = Water solute + Water pressure |
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The addition of solutes _________ water pressure |
REDUCES |
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Physical pressure ___________ water pressure. |
INCREASES |
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Negative pressure __________ water pressure. |
DECREASES |
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Aquaporins |
transport proteins in the cell membrane that allow the passage of water - increase the rate water diffuses down its water potential gradient |
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In most plant tissues, the ___________ and the _____________ are continous from cell to cell. |
cell walls and cytosol |
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Plasmodesmota |
connect the cytosolic compartments of neighboring cells |
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Symplast |
Cytoplasmic continuum |
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Apoplast |
the continuum of cell walls and extracellular spaces |
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Water and minerals can travel through a plant by three routes |
Transmembrane route: out of one cell, across a cell wall, and into another cell Symplastic route: via the continuum of cytosol Apoplastic route: via the the cell walls and extracellular spaces |
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Bulk Flow |
The movement of fluid driven by pressure |
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Endodermis |
innermost layer of cells in the root cortex surrounds the vascular cylinder, and is last checkpoint for selective passage of minerals from the cortex into vascular tissue
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Apoplast |
free diffusional space outside the plasma membrane. It is interrupted by the Casparian strip in roots, by air spaces between plant cells and by the plant cuticle. |
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Casparian Strip |
a belt made of suberin, a waxy material impervious to water and dissolved minerals blocks transfer of minerals (decides what gets through) |
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Is the sap pushed upward from the roots, or is it pulled upward by the leaves? |
Mostly pulled upwards by negative pressure (but there are exceptions -- those plants with dots of water at the top) |
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Name of mechanism that moves sap against gravity |
Transpiration - cohesion - tension mechanism |
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Xerophytes |
plants adapted to arid climates |
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Modifications of xerophytes |
Thick cuiticle Highly reflective leaves Hairy leaves - to trap water Stomata concentrated on lower surface to protect from dry wind |
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Phloem sap |
an aqueous solution that is mostly sucrose – may contain minerals, amino acids, and hormones It travels from a sugar source to a sugar sink |
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Sugar source |
Organ that is a net producer of sugar (mature leaves) |
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Sugar sink |
Organ that is a net consumer of sugar (tuber, bulb) |
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Plasmodesmota can..... |
Can change permeability and number Can open and close based on pH, calcium levels, or turgor pressure Can lose function during differentiation |
