Phototropism exam Flashcards
Phototropism exam
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Phototropism Growth of a plant towards or away from light. What is the role of auxin in phototropism? Auxin facilitates growth towards light by creating asymmetric growth patterns. Phytochromes Photoreceptors that detect red and far-red light, influencing processes like flowering and circadian rhythms. How do plants detect light? Plants use photoreceptors such as phytochromes and cryptochromes to detect light wavelengths. Photomorphogenesis Plant growth in response to different spectrums of light. What is the acid growth hypothesis? It explains how auxin causes cell elongation by pumping protons into the cell wall, allowing water to enter and expand the cell. Etiolation Plant responses to the absence of sunlight, such as growing towards the sun and having longer internodes. What is the function of cryptochromes? Photoreceptors that detect blue light and influence circadian rhythms in plants. Phototropins Blue light photoreceptors involved in phototropism and stomata opening and closing. What is the role of phytochromes in shade avoidance? Phytochromes detect far-red light, causing plants to lengthen stems or induce branching to grow into direct light. Signal Transduction The process by which a signal is carried through the cell, leading to a response. What is the Colin D. Wendt hypothesis? It states that auxin moves from the light side to the shade side of the plant, causing asymmetric growth. Photoperiodism Physiological responses of plants to the lengths of day and night. What is vernalization? A pretreatment with cold necessary for some plants to bloom in response to photoperiod. Florigen The hypothetical hormone believed to induce flowering in plants. What is the role of second messengers in signal transduction? Intracellular signaling molecules that carry the signal within the cell. Chlorosis A lack of chlorophyll in plants, often due to an absence of sunlight. What is the function of expansins? Proteins that loosen hydrogen bonds in cellulose, allowing water to enter the cell wall. Circadian Rhythms Daily cycles in plants that influence hormone concentration and other physiological processes. What is the red-far red switch? A mechanism where phytochromes switch between forms in response to red and far-red light, helping plants detect light and shade. Auxin A plant hormone responsible for growth towards light and other functions. What is the role of photoreceptors in phototropism? Photoreceptors detect light and initiate the growth response towards or away from it. Phyllotaxy The arrangement of leaves on a stem. What is the role of hormones in plant signaling? Hormones affect gene expression, cell division, and growth, mediating plant responses to environmental stimuli. Apical Dominance The phenomenon where the central stem of the plant is dominant over other side stems. What is the function of proton pumps in the acid growth hypothesis? Proton pumps concentrate protons in the cell wall, leading to water entry and cell elongation. Photoreceptors Proteins that respond to light and initiate plant responses. What is the role of blue light in phototropism? Blue light is detected by phototropins and is crucial for phototropism and photosynthesis. Signal Amplification A process where a few signaling molecules have a large effect, amplifying the signal.