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21 Cards in this Set
- Front
- Back
1. What is the definition of a hormone?
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substance produced in 1 part of the body and transported to another where it causes physiological effects
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2. Name 3 major functions of Gibberellins.
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seed germination, fruit development, stem growth
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3. Describe the mechanism of seed germination involving gibberellins. What is the economic significance of this?
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Embryo releases hormone
Causes aleurone layer in seed coat to release enzymes: breaks down starch into sugars Becomes nutrient for the seed Used in alcohol production |
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4. Why are gibberellins often sprayed onto seedless fruits?
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causes fruit development so it helps enlarge fruits
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5. What is "bolting" and what hormone functions in this process?
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Gibberellins; a quick elongation of a flowering stem
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6. Name 3 functions of the plant hormone auxin.
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phototropism, gravitropism, apical dominance
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7. What is phototropism?
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-movement toward light
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8. How is phototropism accomplished in plants?
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auxin concentrates on the dark side os a shoot, causes cells to elongate, pushes stem toward light
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9. What is gravitropism and how is it accomplished in plants?
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movement relative to gravity; auxin pushes the shoot towards light (same way as photo)
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10. How do roots and shoots function differently with respect to gravitropism?
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roots: positively gravitrophic
shoots: negatively gravitrophic |
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11. How does auxin work to expand/elongate cells?
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loosens cellulose microfibrils, causes rapid expansion
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12. What is apical dominance and what controls it?
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-auxin inhibits growth of lateral branches--
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13. What is the function of "releasing" apical dominance?
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a damaged apical meristem stops auxin production, allows for growth of branches
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14. Name one function of cytokinins?
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balance of cytokinins & auxins regulates plant growth
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15. Name two functions of ethylene (as a plant hormone).
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fruit ripening, apical hook
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16. How is ethylene used commercially?
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sprayed on fruit to help ripen it
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17. What is an apical hook and where does it occur?
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? (12/21)
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18. What are phytochromes, what are the 2 chemical forms, and how are these forms induced?
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photoreceptor proteins:
Pr absorbs red light Pfr Pfr absorbs far red light Pr |
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19. What is a major function of phytochromes?
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induces germination (only Pfr form after exposure to red light)
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20. What is the name of the mechanism that explains water transport in plants?
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Transpiration Cohesion Tension Model
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21. What is the name of the mechanism that explains sugar transport in plants?
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Pressure Flow (from high concentration to low concentration)
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