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26 Cards in this Set
- Front
- Back
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Define traspiration
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Transpiration is the loss of water vapour from the leaves and stems of plants
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What are the key features of a monocotyledonous plant?
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1) Parallel veins,
2) Flower organs are in multiples of 3 3) One cotyledons 4) Fibrous, highly branching root structure |
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What are the key features of a dicotyledonous plant?
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1) Net-like ventration/veins,
2) Flower organs are in multiples of 4 or 5 3) two cotyledons 4) Tap root structure with lateral roots |
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What are the three ways plants uptake water?
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1) Mass flow/apoplast pathway - the water travels in the free space between the cell wall and the plasma membrane, this is the main pathway
2) Diffusion/symplast pathway - the water travels through the cytoplasm and cytoplasmic connections. This is not a main pathway because the organelles create resistance against water flow. 3) Osmosis- how individual plant cells absorb water. The water travels from vacuole to vacuole and is driven by the gradient in osmotic pressure. |
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How do terrestrial plants support themselves?
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1) Cell strength (parenchyma and collenchyma)
2) Cell turgidity 3) Lignified xylem vessels - (walls of xylem vessels are strengthened by the chemical lignin) |
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What regulates the opening and closing of stomatal pores?
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Guard cells
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Which hormone causes the closing of stomata?
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Abscisic acid
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What are the abiotic factors that affect the rate of transpiration?
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1) Light
2) Temperature 3) Wind 4) Humidity |
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What is the effect of light on the rate of transpiration?
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Increased light intensity increases the rate of transpiration because it opens the stomatal pores wider allowing water vapour diffuse out more easily.
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What is the effect of temperature on the rate of transpiration?
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Higher temperatures increase the rate of transpiration because it increases the rate of evaporation which creates a higher vapour potential in the free air space of the leaf.
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What is the effect of increased wind speed on the rate of transpiration?
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Increased wind speed increases the rate of transpiration. The wind moves any water vapour that was accumulating around the exterior of the leaf. This enhances the difference in the concentration gradient between the inside and the outside of the leaf.
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What is the effect of decreased humidity on the rate of transpiration?
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Decreased humidity increases the rate of transpiration because there is less water vapour in the area surrounding the leaf. This means that there is a higher concentration gradient between the inside and outside of the leaf.
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What is the effect of decreased humidity on the rate of transpiration?
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Decreased humidity increases the rate of transpiration because there is less water vapour in the area surrounding the leaf. This means that there is a higher concentration gradient between the inside and outside of the leaf.
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What are the adaptations of xyerophytes that help reduce transpiration?
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- A thick, waxy cuticle helps prevent water loss
- Deep roots exploit a deep water table in the soil - A reduced number of stomata reduces the outlets through which water vapour can diffuse - Layer of hairs on epidermis traps moist air and reduces the rate of diffusion |
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What is translocation?
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Translocation is the movement of sugars and amino acids in the phloem.
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What are the structures in an flowering plant (angiosperm)?
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Stigma, style, ovary, sepal, petals, anthem and filament.
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What it pollination?
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Pollination is the transfer of pollen from the anther to the stigma
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What is fertilisation?
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Fertilisation is the fusion of a male gamete (pollen grain) and a female gamete (ovary) to form a zygote.
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What is seed dispersal?
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Seed dispersal is the carrying of the seed (product of fertilised ovary) away from the vicinity of the parent plant for reasons to do with competition.
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Why may dormancy be imposed on a seed?
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- Incomplete seed development
- The presence of plant growth regulators - An impervious seed coat which is eventually made permeable (e.g. through abrasion) |
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What are the conditions required for the germination of a typical seed?
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- Oxygen for aerobic respiration
- Water to metabolically activate cells - Temperature for the optimal functions of enzymes. |
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What is phytochrome?
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Phytochrome is a highly reactive blue-green pigment (photoreceptor). There are two types: phytochrome-red (blue pigment, 660nm) and phytochrome-far-red (blue-green pigment, 730nm).
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What is seed dispersal?
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Seed dispersal is the carrying of the seed (product of fertilised ovary) away from the vicinity of the parent plant for reasons to do with competition.
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Why may dormancy be imposed on a seed?
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- Incomplete seed development
- The presence of plant growth regulators - An impervious seed coat which is eventually made permeable (e.g. through abrasion) |
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What are the conditions required for the germination of a typical seed?
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- Oxygen for aerobic respiration
- Water to metabolically activate cells - Temperature for the optimal functions of enzymes. |
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What is phytochrome?
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Phytochrome is a highly reactive blue-green pigment (photoreceptor). There are two types: phytochrome-red (blue pigment, 660nm) and phytochrome-far-red (blue-green pigment, 730nm).
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