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23 Cards in this Set
- Front
- Back
Hormones are ________.
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chemical signals that coordinate different parts of an organism.
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What do plant hormones affect?
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Cell division, elongation and differentiation
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Tropism is _______.
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Any result in curvature of organs toward or away from a stimulus.
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Auxin does what?
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Triggers cell elongation by the loosening of cellulose in the cell walls due to hydrogen
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How does auxin produce phototropism?
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Auxin accumulates in cells on the side of the plant opposite the source of light and stimulates their elongation.
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When auxin is produced in seeds, what happens?
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Promotes fruit development
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Cytokinins do what?
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Work together with auxin to control cell division and differentiation
And slow the aging of certain plant organs |
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What produces cytokinins?
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actively growing tissues such as meristems, embryos, and fruits
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Where does the majority of stem growth in a plant occur?
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Apical Meristem
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Apical dominance- what is it and what causes it?
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Prevents a plant from becoming "bushier"
Cytokinins, auxin and other factors |
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Gibberellins-
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Stem elongation, fruit growth and seed germination
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How does GA work in seeds?
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It is released once water is absorbed, and it triggers germenation
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What hormone slows growth?
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Absisic Acid (ABA)
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How does ABA play a major role in drought tolerance?
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ABA accumulates in the leaves and causes stomata to close when plants begin to wilt
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Ethylene mediates what?
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Triple Response
Cell Death Leaf Abscission Fruit Ripening |
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What is the Triple response?
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Slowing of stem elongation,
A thickening of the stem, and horizontal growth |
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True or False? Plants display daily circadian rhythms, indicating an internal, biological clock
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True
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Short Day Plants are what?
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plants that flower when days are short and nights are long
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Long Day plants are what?
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plants that flower when days are long and nights are short
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Flowering is a response to day lenght or night lenght?
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Night lenght
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Gravitopism is ?
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Plants response to gravity
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How does auxin produce gravitropism in a plant that is placed on its side?
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Auxin accumulates on the lower surface of the root and inhibits elongation of cells in that region.
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Thigmotropism is?
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Directional growth in response to touch
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