Skip to main content
Pearson+ LogoPearson+ Logo

Phototropism quiz #2 Flashcards

Phototropism quiz #2
Control buttons has been changed to "navigation" mode.
1/15
  • What do phototropism and geotropism enable plants to do?
    Phototropism and geotropism enable plants to grow towards light and respond to gravity, respectively, optimizing their growth and survival.
  • Why is phototropism beneficial to plants?
    Phototropism is beneficial because it allows plants to maximize light absorption for photosynthesis, enhancing their energy production and growth.
  • What is phototaxis?
    Phototaxis is the movement of organisms towards or away from a light source, often seen in microorganisms like algae.
  • Which of the following plant growth responses is primarily due to the action of auxins? A) Phototropism B) Geotropism C) Phototaxis D) Circadian rhythm
    A) Phototropism
  • Why is phototropism important for plants?
    Phototropism is important because it directs plant growth towards light, ensuring efficient photosynthesis and survival.
  • How is phototropism beneficial to a plant?
    Phototropism benefits a plant by directing its growth towards light sources, optimizing photosynthesis and energy acquisition.
  • Which pigment is responsible for detecting the photoperiod of a plant?
    Phytochromes are responsible for detecting the photoperiod, influencing flowering and other seasonal responses.
  • What role do phytochromes play in plant growth?
    Phytochromes detect light wavelengths and influence processes like flowering and circadian rhythms in plants.
  • How do auxins contribute to phototropism?
    Auxins facilitate asymmetric growth by concentrating on the shaded side of the plant, causing it to bend towards the light.
  • What is the acid growth hypothesis related to auxins?
    The acid growth hypothesis suggests that auxins promote cell elongation by increasing proton concentration in cell walls, allowing water to enter and expand cells.
  • What is phototropism and how does it benefit plants?
    Phototropism is the growth of a plant toward or away from light. It benefits plants by allowing them to maximize light absorption for photosynthesis, which is essential for their survival.
  • Describe the acid growth hypothesis and its role in phototropism.
    The acid growth hypothesis states that auxin stimulates proton pumps to release protons into the cell wall, loosening cellulose bonds and allowing water to enter. This causes cell elongation, especially on the shaded side, leading to bending toward light.
  • How do phytochromes help plants detect shade and regulate growth?
    Phytochromes exist in two forms that switch based on red or far-red light absorption. In shade, far-red light predominates, triggering phytochromes to induce stem elongation or branching, helping the plant reach better light.
  • What is the function of cryptochromes in plant light responses?
    Cryptochromes are blue light photoreceptors that help regulate circadian rhythms and influence plant behaviors such as leaf opening and closing in response to day-night cycles.
  • What is photomorphogenesis, and how does it differ from phototropism?
    Photomorphogenesis is the growth and development of plants in response to different light spectra, affecting overall form and structure. Phototropism specifically refers to directional growth toward or away from light.