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291 Cards in this Set
- Front
- Back
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hydroponic culture
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growing plants by bathing them in nutrient solutions that are aerated as opposed to soil; can be used as a method to determine which of the mineral elements are essential nutrients to a plant; a control plant is bathed in a solution of minerals and an experimental plant is bathed in a solution of the minerals minus the one to be tested; if it wilts then the mineral is essential
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Name nine macronutrients essential to plants
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carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorous, potassium, calcium, magnesium
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Why is nitrogen essential to plants?
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Component of nucleic acids, proteins, hormones and coenzymes
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Why is sulfur essential to plants?
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Component of proteins, coenzymes
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Why is potassium essential to plants?
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Cofactor that functions in protein synthesis; major solute functioning in water balance; operation of stomata
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Why is calcium essential to plants?
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Important in formation and stability of cell walls and in maintenance of membrane structure and permeability; activates some enzymes; regulates many responses of cells to stimuli
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Why is magnesium essential to plants?
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Component of chlorophyll; activates many enzymes
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eight micronutrients essential to plants
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chlorine, iron, boron, manganese, zinc, copper, molybdenum, nickel
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Why is chlorine essential to plants?
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Required for water-splitting step of photosynthesis; functions in water balance
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Why is iron essential to plants?
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Component of cytochromes; activates some enzymes
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Why is boron essential to plants?
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cofactor in chlorophyll synthesis; may be involved in carbohydrate transport and nucleic acid synthesis
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Why is manganese essential to plants?
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Active in formation of amino acids; activates some enzymes; required for water-splitting step of photosynthesis
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Why is zinc essential to plants?
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Active in formation of chlorophyll; activates some enzymes
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Why is copper essential to plants?
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Component of many redox and lignin-biosynthetic enzymes
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Why is molybdenum essential to plants?
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Essential for nitrogen fixation; cofactor that functions in nitrate reduction
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Why is nickel essential to plants?
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Cofactor for an enzyme functioning in nitrogen metabolism
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chlorosis
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the yellowing of leaves caused by an inability to synthesize chlorophyll
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What do mineral deficiency symptoms depend on?
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The role of the nutrient in the plant and also its mobility within the plant
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humus
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a residue of partially decayed organic material
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topsoil
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a mixture of particles derived from rock, living organisms, and humus
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horizons
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distinct soil layers
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loams
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the most fertile soils, made up of roughly equal amounts of sand, silt and clay
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What does the presence of clay in a soil help to do?
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Prevent leaching of mineral nutrients during heavy rain or irrigation because materials bind to it
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cation exchange
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when plants secrete H+ to displace positively charged minerals so that it can absorb them
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phytoremediation
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when a plant is able to uptake heavy metals and other pollutants and concentrate them in easily harvest portions of the plant; used to detoxify soils
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nitrogenase
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an enzyme complex that catalyzes nitrogen fixation
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Plants acquire their nitrogen mainly from what form of nitrogen?
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Nitrate, created by nitrification
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nodules
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swellings in a legume’s roots composed of plant cells that contain nitrogen-fixing bacteria
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rhizobium
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bacteria that fix nitrogen
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bacteroids
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the form Rhizobium bacteria assume inside a nodule
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Why do some root nodules have a reddish color?
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Molecules called leghemoglobin inside the nodules act as an oxygen “buffer”
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What do legumes secrete to initiate communication with a Rhizobium?
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Flavonoids
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What do bacteria respond to flavonoids with?
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Secreting enzymes that catalyze production of species-specific molecules called Nod factors
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chlorophyll
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the green pigment located within chloroplasts
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mesophyll
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the tissue in the interior of the leaf
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Where are chloroplasts mainly found?
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In the cells of the mesophyll
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How many chloroplasts does a typical mesophyll cell have?
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30 to 40
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thylakoid space/lumen
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the space inside a thylakoid
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thylakoid
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the site of the light reactions
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stroma
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the site of the Calvin reactions
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grana
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stacks of thylakoids
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Where is the oxygen given off by plants derived from?
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water
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Who proposed that plants split water instead of carbon dioxide?
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van Niel
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What are the two stages of photosynthesis?
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light reaction and Calvin cycle
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photophosphorylation
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the addition of a phosphate group to ADP from light reactions
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NADP+
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the molecule that temporarily stores energized electrons in the light reaction
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carbon fixation
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incorporation of carbon into organic compounds
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wavelength
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the distance between the crests of electromagnetic waves
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pigments
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substances that absorb visible light
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spectrophotometer
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measures the ability of a pigment to absorb various wavelengths of light
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absorption spectrum
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a graph plotting a pigment’s light absorption
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Who first demonstrated the action spectrum for photosynthesis?
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Thomas Engelmann
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Chlorophyll a
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the main pigment in photosynthesis; the only kind that can participate directly in the light reactions; is blue-green
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Chlorophyll b
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an accessory pigment; is yellow-green
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carotenoids
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an accessory pigment that are various shades of yellow and orange
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What are the two important functions of carotenoids?
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Absorbing a broader spectrum of colors and photoprotection; dissipating excessive light energy
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What atom does chlorophyll have at its center?
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Magnesium
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What is the afterglow caused by excited electrons falling back to ground state called?
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Fluorescence
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photosystem
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systems that package together chlorophyll, proteins, and other kinds of smaller organic molecules in the thylakoid membrane
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antenna complex of a photosystem
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a cluster of a few hundred chlorophyll a, chlorophyll b, and carotenoid molecules
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reaction center
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the region of the photosystem where the first light-driven chemical reaction of photosynthesis occurs; contains a special chlorophyll a molecule
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primary electron acceptor
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a special molecule in the reaction center that gets reduced (gains an electron) by the chlorophyll a
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photosystem I
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the photosystem that is best at absorbing light of wavelength 700 nm (the far-red part)
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photosystem II
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the photosystem that is best at absorbing light of wavelength 680 nm (red part)
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What causes the difference in the absorption spectra of photosystem I and photosystem II?
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The chlorophyll are associated with different proteins in the thylakoid membrane
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noncyclic electron flow
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the predominant route during the light reaction
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When does the water-splitting step of photosynthesis occur?
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In noncyclic electron flow, when Photosystem II gets excited and after needs to be reduced; water is split up to get electrons
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What are the molecules in the first electron transport chain for photosynthesis?
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Plastoquinone (electron carrier), a complex of two cytochromes, and plastocyanin (a copper-containing protein)
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What are the molecules in the second electron transport chain for photosynthesis?
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Ferredoxin (iron-containing protein), cytochromes, plastoquinone
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NADP+ reductase
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an enzyme that transfers electrons from Fd to NADP+
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What does the first electron transport chain for photosynthesis create?
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ATP
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What does the second electron transport chain for photosynthesis create?
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NADPH
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Explain the steps of noncyclic electron flow briefly:
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light excites both photosystem II and photosystem I. In photosystem II, the electron is carried through a transport chain that produces ATP and reduces photosystem I back to ground state. A water is split to get its electrons to reduce photosystem II back to ground state. In photosystem I, the electron is carried through another transport chain that produces NADPH.
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cyclic electron flow
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when Fd cycles back to the cytochrome complex and back onto photosystem I, thus generating more ATP but no O2 or NADPH
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why is cyclic electron flow sometimes necessary?
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The Calvin cycle consumes more ATP than it does NADPH, so more ATP needs to be made than NADPH
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What is the function of the thylakoid space?
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As an H+ reservoir for chemiosmosis
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What is the carbohydrate produced directly from the Calvin cycle called?
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G3P (glyceraldehydes-3-phosphate)
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What does G3P stand for?
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Glyceraldehydes-3-phosphate
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What is the molecule that CO2 is attached to in the Calvin cycle?
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Ribulose bisphosphate (RuBP)
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rubisco
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the enzyme that catalyzes the incorporation of carbon
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What does rubisco stand for?
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RuBP carboxylase
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What is the most abundant protein in chloroplasts?
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rubisco
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What is the second carbon product formed in the Calvin cycle?
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1,3 bisphosphoglycerate
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What is formed immediately after CO2 is fixed?
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Two molecules of 3-phosphoglycerate
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What does the net synthesis of one G3P molecule take?
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9 molecules of ATP and 6 molecules of NADPH
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C3 plants
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plants in which the first organic product of carbon fixation is a 3 carbon compound 3-phosphoglycerate
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photorespiration
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when plants use Rubisco to break down O2 to make CO2; generates no ATP and produces no food
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C4 plants
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plants in which the first organic product of carbon fixation is a four-carbon compound
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Examples of C3 plants
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rice, wheat, soybeans
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Examples of C4 plants
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sugarcane, corn, grass
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What are the two distinct types of photosynthetic cells in C4 plants?
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Bundle-sheath cells and mesophyll cells
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bundle-sheath cells
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cells that are arranged into tightly packed sheaths around the veins of the leaf
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Mesophyll cells (C4 plants)
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loosely arranged cells between the bundle sheath cells and the leaf surface
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Where is the Calvin cycle confined to in C4 plants?
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The chloroplasts of the bundle sheath
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What does PEP stand for?
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Phosphoenolpyruvate
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PEP carboxylase
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the enzyme that adds CO2 to PEP
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What is the first product created in C4 photosynthesis?
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Oxaloacetate
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Why do C4 plants make a 4-carbon compound?
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This compound releases CO2 to be reassimilated into organic material, thus keeping the CO2 levels high
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What are the four main groups of land plants?
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Bryophytes, pteridophytes, gymnosperms, angiosperms
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What are the most common bryophytes?
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Mosses
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How are bryophytes distinguished from algae?
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Offspring develop from multicellular embryos that remain attached to the “mother” plant
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bryophytes
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mosses
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How are bryophytes distinguished from other land plants?
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Bryophytes have no vascular tissue
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vascular plants
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plants with vascular tissue; includes gymnosperms, pteridophytes and angiosperms
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vascular tissue
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when cells are joined into tubes that transport water and nutrients throughout the plant body
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pteridophytes
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have spores instead of seeds; includes ferns
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seed plants
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plants that reproduce with seeds, includes gymnosperms and angiosperms
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seed
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a plant embryo packaged along with a food supply within a protective coat
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When did the first vascular plants with seeds occur?
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Near the end of the Devonian period about 360 million years ago
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When did flowering plants occur?
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In the early Cretaceous period about 130 million years ago
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gymnosperms
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conifers
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Angiosperms
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flowering plants
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What algae did plants evolve from?
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Charophyceans
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rosette cellulose-synthesizing complex
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rose-shaped arrays of proteins that synthesize the cellulose microfibrils of cell walls; distinguishes them from algae
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phragmoplast
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an alignment of cytoskeletal elements and Golgi-derived vesicles that occurs during cross-wall synthesizing in cell division
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What four features link plants to charophyceans?
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Rosette cellulose-synthesizing complexes, presence of peroxisomes, similar sperm cell structures, similar details of cell division
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What five features distinguish plants from charophyceans?
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Apical meristems; multicellular, dependent embryos; alternation of generations; walled spores produced in sporangia; multicellular gametangia
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apical meristems
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localized regions of cell division at the tips of shoots and roots
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embryophytes
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the characteristic of a multicellular, dependent embryo
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alteration of generations
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the alternation of two multicellular body forms, each form producing the other
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gametophyte
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haploid generation that undergoes mitosis to produce gametes
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sporophyte
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diploid generation from the mitotic division of a zygote that divides meiotically to produce haploid spores
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spore
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a reproductive cell that can develop into a new organism without fusing with another cell; divides mitotically to produce gametophytes
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What distinguishes alternation of generations as a special type of haploid-diploid sexual cycle?
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BOTH stages are represented by multicellular bodies
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sporopollenin
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a polymer that makes the walls of plant spores very tough and resistant to harsh environments
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What is the most durable organic material known?
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Sporopollenin
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sporangia
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multicellular organs found on the sporophyte that produce the spores
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gametangia
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multicellular organs that produces gametes
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archegonia
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female gamentangia
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ectomycorrhizae
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when the mycelium of a fungus forms a dense sheath over the surface of the root
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What are ectomycorrhizae common in?
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woody plants
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endomycorrhizae
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when the mycelium of a fungus actually extend inward into the cell wall
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What percentage of mycorrhizae are endomycorrhizaes?
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90%
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arbuscles
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dense knotlike structures that endomycorrhizae form once they have penetrated the cell wall
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epiphyte
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an autotrophic plant that nourishes itself but grows on the surface of another plant
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flowers
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specialized shoots bearing the reproductive organs of the angiosperm sporophyte
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What are the four kinds of floral organs?
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Sepals, petals, stamens, carpels
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receptacle
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where the floral organs are attached to
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stamen
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the male reproductive organ
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carpel
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the female reproductive organ
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sepals
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floral nonreproductive organs that enclose and protect the floral bud before it opens; green and more leaflike in appearance than other floral organs
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petals
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floral nonreproductive organs that advertise the flower to pollinators
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What does a stamen consist of?
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Filament (stalk) and anther
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anther
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part of the stamen, produces pollen
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What does a carpel consist of?
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An ovary and a style (middle neck)
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stigma
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a sticky structure at the top of the carpel that serves as a landing platform for pollen
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ovary
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a structure within the carpel that contains ovules
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ovule
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structure within ovary, is basically the egg
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pollen grains
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male gametophytes
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embryo sacs
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female gametophytes
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What part of an angiosperm develops into a fruit?
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ovary
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What part of an angiosperm develops into a seed?
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ovule
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complete flowers
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flowers that have all four floral organs
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incomplete flowers
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flowers that lack one or more of the four floral parts
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bisexual flower
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a flower that has both stamens and carpels
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unisexual flower
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a flower that is missing either stamens or carpels
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staminate
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a unisexual flower that is missing a carpel
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carpellate
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a unisexual flower that is missing a stamen
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monoecious
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when staminate and carpellate flowers are located on the same individual plant
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dioecious
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when staminate flowers and carpellate flowers are on separate plants
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microsporocytes
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the diploid cells within the sporangia (pollen sacs) of an anther
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microspores
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the haploid cells that eventually give rise to a male gametophyte
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How many microspores are formed from a microsporocyte?
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4
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What two cells does the microspore produce from mitosis?
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generative cell and tube cell
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generative cell
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a cell produced from the microspore by mitosis, will eventually produce sperm
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tube cell
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a cell produced from the microspore by mitosis, will develop into the pollen tube
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megaspore
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the haploid product of the sporangium of the ovule (megasporocyte); typically are four of them
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What happens to the four megaspores?
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Only one survives
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micrpyle
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a gap in the integument of the ovule
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endosperm
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a food-storing tissue of the seed
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What process gives rise to the endosperm?
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one sperm combining with the two polar nuclei in an ovule to form a triploid (3n) nucleus
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double fertilization
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the union of two sperm cells with different nuclei of the embryo sac
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hypocotyl
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the embryonic axis below the point where cotyledons are attached
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radicle
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embryonic root
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epicotyl
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portion of the embryonic axis above the cotyledons
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plumule
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shoot tip with a pair of miniature leaves
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greening
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when potatoes that have dark-sprouted start to grow like a normal plant
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phytochrome
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the receptor involved in greening in plants
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Where does the phytochrome that functions in greening occur?
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cytoplasm
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aurea
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a tomato mutant that demonstrated the requirement for phytochrome in greening
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second messengers
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small, internally produced chemicals that transfer and amplify the signal from the receptor to proteins that cause the specific response
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auxin
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hormone that stimulates stem elongation, root growth, cell differentiation and braniching
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Where is auxin produced?
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in the embryo of a seed, meristems of apical buds, young leaves
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What was the first plant hormone to be discovered?
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auxin
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What is the natural auxin occuring in plants also known as?
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indoleacetic acid (IAA)
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cytokinin
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hormone that affects root growth and differentiation, stimulates cell division and growth, germination, delays senescence
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gibberellins
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promotes seed and bud germination, stem elongation and leaf growth; stimulates flowering and development of fruit, affects root growth and differentiation
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Where is gibberellin produced?
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meristems of apical buds and roots, young leaves, embryo
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abscisic acid
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hormone that inhibits growth; closes stomata during water stress; counteracts breaking of dormancy
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Where is abscisic acid produced?
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leaves, stems, roots, green fruit
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ethylene
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hormone that promotes fruit ripening, opposes some auxin effects; promotes or inhibits growth and development of roots, leaves, flowers
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Where is ethylene found?
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tissues of ripening fruits, nodes of stems, aging leaves and flowers
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brassinosteroids
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inhibits root growth; retards leaf abscisssion; promotes xylem differentiation
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synergids
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two cells that flank the egg cell and function in the attraction and guidance of the pollen tube
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polar nuclei
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two nuclei in an embryo sac that share the cytoplasm of the large central cell
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integument
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protective layers of sporophytic tissue
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What cells are in the embryo sac?
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One egg cell, two synergids, three antipodal cells, two polar nuclei
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self-incompatibility
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the ability of a plant to reject its own pollen and the pollen of closely related individuals
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eudicots
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largest class of angiosperms
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amorella
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oldest angiosperm
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three basic organs of plants:
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roots, stems, leaves
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cotyledons
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seed leaves
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monocots
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orchids, bamboos, palms, lilies, yucca, grasses
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dicots
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roses, beans, sunflowers, oaks
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differences between monocots and dicots:
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Monocots: one cotyledon, parallel leaf veins, vascular bundles arranged in stems, fibrous root system, floral parts in multiples of three
Dicots: two cotyledons, veins usually netlike, vascular bundles arranged in ring, taproot present, floral parts in multiples of four or five |
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root system
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subterranean
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shoot system
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ground level, stems and leaves
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terminal bud
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shoot apex
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fibrous root systems
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monocots, mat of thin roots
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taproot system
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dicots, one large, vertical root w/ smaller lateral roots
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root hairs
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increases surface area of root enormously
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adventitious
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Any plant part that grows in an atypical location (some plants have orots rising aboveground from stems or even leaves, i.e. corn)
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vegetative shoot system
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leaf bearing
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reproductive shoot system
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flower bearing
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stem
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an alternating system of nodes and internodes
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nodes
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points at which leaves are attached
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internodes
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stem segments between nodes
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axil
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angle formed by each leaf and stem
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axillary bud
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structure that has the potential to form a vegetative branch; most are dormant
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apical dominance
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phenomenon where presence of the terminal bud is partly responsible for inhibiting the growth of axillary buds
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modified shoots
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stolons, rhizomes, tubers, bulbs
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stolons
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grow on surface of ground and enable a plant to colonize large areas asexually when the single parent plant fragments into many smaller offspring, i.e. “runners” of strawberry plants
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rhizomes
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horizontal stems similar to stolons but underground, i.e. ginger plants
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tubers
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swollen ends of rhizomes specialized for storing food, i.e. potatoes
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bulbs
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vertical, underground shoots mostly of swollen bases of leaves that store food, i.e.. onions
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leaves
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main photosynthetic organ of most plants, consist of blade and petiole
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petiole
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stalk of leaf, joins leaf to node of stem; many monocots lack petioles
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how to classify plants:
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leaf shape, spatial arrangement of leaves on a stem pattern of leaf’s veins
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tissue systems of plant organs:
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dermal, vascular, ground
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dermal tissue
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aka epidermis, single layer of tightly packed cells that covers and protects all young parts of the plant
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cuticle
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waxy coating of epidermis of leaves and most stems
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vascular tissue
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is continuous throughout the plant, involved in transport of materials between roots and shoots; consists of xylem, and phloem
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xylem
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conveys water and dissolved minerals upward from roots into shoots
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phloem
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transports food made in mature leaves to roots and nonphotosyntehtic parts of shoot system
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tracheids and vessel elements
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water-conducting elements of xylem, elongated cells that are dead at functional maturity
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pits
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thinner regions where only primary walls are present
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xylem vessels
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long micropipes that are composed of vessel elements aligned end to end
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sieve-tube members
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tubes that transport sucrose and other organic compounds through the phloem; alive at functional maturity, but lack organelles
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sieve plates
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end walls b/w sieve-tube members in angiosperms; have pores that facilitate flow of fluid from cell to cell along sieve tube
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companion cell
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nonconducting cell alongside each sieve-tube member, has organelles like nucleus and ribosome to serve sieve-tube members
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ground tissue
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simply tissue that is neither dermal tissue nor vascular tissue, divided into pith and cortex in dicot stems, has diverse functions
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pith
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part of ground tissue, internal to vascular tissue
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cortex
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part of ground tissue, external to vascular tissue
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three basic types of plant tissue:
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parenchyma, collenchyma, sclerenchyma
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protoplast
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cell contents exclusive of the cell wall
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parenchyma cells
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have relatively thin and flexible primary walls, lack secondary walls, protoplast has large central vacuole, least specialized (known as “typical” plant cells), perform most metabolic functions of plant
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collenchyma cells
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thicker uneven primary walls, grouped in strands or cylinders, support young parts of plant shoot without restraining growth
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sclerenchyma cells
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supporting cells, but have thick secondary walls strengthened by lignin, cannot elongate and occur in regions of plants that have stopped growing; many are dead at functional maturity, xylem components are sclerenchyma cells, also fibers and sclereids
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fibers
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type of sclerenchyma cell, specialized entirely in support, long, slender, tapered, i.e. hemp and flax
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sclereids
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type of sclerenchyma cell, shorter and irregular in shape, i.e. nutshells and seed coats
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biennial
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A plant whose life span is two years, mostly those with intervening cold period (Winter) b/w vegetative growth (spring/summer) and flowering (2nd spring/summer)
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perennials
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Plants that live many years
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meristems
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perpetually embryonic tissues
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initials
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Cells that remain as wellsprings of new cells in the meristem
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derivatives
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new cells that are displaced form the meristem, continue to divide until they are specialized
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apical meristems
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located at tips of roots and in buds of shots, supply cells for plant to grow in length
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primary growth
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elongation of apical meristems
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secondary growth
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woody plants only, progressive thickening of the roots and shoots formed earlier by primary growth, product of lateral meristems
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lateral meristems
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cylinders of dividing cells extending along the length of roots and shoots
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primary plant body
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parts of the root and shoot systems produced by apical meristems
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root cap
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thimblelike, physically protects meristem of root, secretes polysaccharide slime that lubricates soil around growing root tip
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zones of cells at successive stages of primary growth:
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zone of cell division, zone of elongation, zone of maturation
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zone of cell division
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includes apical meristem and derivatives, concentrates on mitosis
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quiescent center
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population of cells near center of apical meristem that divide much more slowly than other meristematic cells, relatively resistant to damage from radiation and toxic chemicals
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protoderm
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first circle of cells just above apical meristem, will produce dermal tissues
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procambium
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2nd circle of cells just above apical meristem, will produce vascular tissue
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ground meristem
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third circle of cells just above apical meristem, will produce ground tissues
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zone of elongation
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zone where cells elongate, pushes root tip ahead
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zone of maturation
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where tissue systems become functionally mature
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stele
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central cylinder of vascular tissue where xylem and phloem develop, produced by procambium
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endodermis
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cylinder one cell thick forms boundary between cortex and stele in roots of both monocots and dicots; innermost layer of cortex
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lateral roots
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arise from pericycle in established roots
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pericycle
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layer of cells that may become meristematic and begin dividing again
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vascular bundles
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strands of vascular tissue in length of stem
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stomata
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tiny pores flanked by guard cells; allows gas exchange between surrounding air and photosynthetic cells inside leaf, major avenues for transpiration
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guard cells
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specialized epidermal cells that border stomata
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mesophyll
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region between upper and lower epidermis where ground tissue of a leaf is centered; consists mainly of parenchyma cells equipped with chloroplasts and specialized for photosynthesis
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palisade parenchyma
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mesophyll on upper part of leaf in dicots, cells are columnar in shape
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spongy parenchyma
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below palisade region, gets name from labyrinth of air spaces through which carbon divide and oxygen circulate around the irregularly shaped cells
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secondary plant body
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consists of tissues produced during secondary growth (diameter growth)
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vascular cambium
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lateral meristem that functions in secondary growth, produces secondary xylem (wood) and secondary phloem
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cork cambium
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produces tough, thick covering for stems and root that replaces epidermis
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ray initials
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alternating regions of cambium cells that produce radial files of parenchyma cells known as xylem rays and phloem rays, separate wedge-shaped sections of secondary vascular tissue
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fusiform initials
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cambium cells within vascular bundles, produce new vascular tissue, forming secondary xylem to the inside of the vascular cambium and forming secondary phloem to the outside
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wood consists mainly of:
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tracheids, vessel elements (angiosperms only), and fibers
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characteristics of early wood:
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relatively large diameters and thin walls, produced during spring
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characteristics of late wood:
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relatively small diameters and thick walls, produced during summer
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suberin
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waxy material that cork cells deposit in walls after they mature and before they die; makes up the Casparian strips
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periderm
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layers of cork and cork cambium; protective coat of secondary plant body that replaces epidermis of primary body
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lenticels
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region where periderm has split open, make cellular respiration for trunk cells possible
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bark
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all tissues external to vascular cambium
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