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Tropisms and Hormones quiz #2

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  • Which response occurs because of the hormone auxin?
    Auxin causes roots to bend toward higher concentrations of the hormone, influencing growth direction.
  • What is the external stimulus in thigmotropism?
    The external stimulus in thigmotropism is touch, which causes plants to respond by growing and wrapping around objects.
  • Which situation most likely involves the hormone gibberellin?
    Gibberellin is involved in stem elongation, fruit growth, and seed germination.
  • How do statoliths help plants sense gravity?
    Statoliths are dense amyloplasts that sink to the bottom of cells, activating sensory signals to help plants sense gravity.
  • What role does ethylene play in plant senescence?
    Ethylene triggers enzymes that degrade cell walls, leading to leaf abscission and fruit ripening.
  • How do plants use action potentials in thigmotropism?
    Plants use action potentials to rapidly respond to touch, allowing movements like the closing of a Venus flytrap.
  • What is the function of cytokinins in plant growth?
    Cytokinins regulate growth by influencing the cell cycle and promoting cell division.
  • How does abscisic acid affect seed dormancy?
    Abscisic acid inhibits germination, maintaining seed dormancy until favorable conditions arise.
  • What is the effect of gibberellins on internode length?
    Gibberellins increase internode length, leading to longer stems in plants.
  • How do plants respond to wind as a physical stimulus?
    Plants restrict vertical growth in response to wind to prevent damage and maintain stability.