Phototropism quiz #3 Flashcards
Phototropism quiz #3
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Which plant hormone is primarily responsible for phototropic responses, and how does it function?
Auxin is the primary hormone responsible for phototropism. It accumulates on the shaded side of the plant, causing those cells to elongate more than those on the light side, resulting in the plant bending toward the light. What are photoreceptors, and which types are involved in detecting light for phototropism?
Photoreceptors are proteins that detect specific wavelengths of light. Phototropins detect blue light and are crucial for phototropism, while phytochromes detect red and far-red light and are involved in other light responses. Explain the role of auxin distribution in the bending of plant stems toward light.
Auxin moves from the light-exposed side to the shaded side of the stem, causing greater cell elongation on the shaded side. This uneven growth bends the stem toward the light source. How do plants use photoreceptors to distinguish between direct sunlight and shade?
Plants use phytochromes to detect the ratio of red to far-red light. High far-red light indicates shade, prompting the plant to adjust growth patterns to seek more direct sunlight. Why is auxin transport described as polar, and what is its significance in plant development?
Auxin transport is polar because it moves in one direction, from shoots to roots, regardless of gravity. This unidirectional movement is crucial for coordinating growth and developmental processes in plants. Which plant hormone is primarily responsible for phototropic responses, and how does it function?
Auxin is the primary hormone responsible for phototropism. It accumulates on the shaded side of the plant, causing those cells to elongate more than those on the light side, resulting in the plant bending toward the light. What are photoreceptors, and which types are involved in detecting light for phototropism?
Photoreceptors are proteins that detect specific wavelengths of light. Phototropins detect blue light and are crucial for phototropism, while phytochromes detect red and far-red light and are involved in other light responses. Explain the role of auxin distribution in the bending of plant stems toward light.
Auxin moves from the light-exposed side to the shaded side of the stem, causing greater cell elongation on the shaded side. This uneven growth bends the stem toward the light source. How do plants use photoreceptors to distinguish between direct sunlight and shade?
Plants use phytochromes to detect the ratio of red to far-red light. High far-red light indicates shade, prompting the plant to adjust growth patterns to seek more direct sunlight. Why is auxin transport described as polar, and what is its significance in plant development?
Auxin transport is polar because it moves in one direction, from shoots to roots, regardless of gravity. This unidirectional movement is crucial for coordinating growth and developmental processes in plants.
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