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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.