Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Phototropins are a type of blue light receptor proteins found in plants. They play a crucial role in mediating various light-dependent processes such as phototropism, chloroplast movement, and stomatal opening.
5 Must Know Facts For Your Next Test
Phototropins absorb blue light using flavin chromophores.
They are primarily involved in the phototropic response, causing plants to grow towards light.
Phototropins consist of two domains: LOV (Light, Oxygen, or Voltage) domains for sensing light and a kinase domain for signal transduction.
In addition to phototropism, they regulate chloroplast positioning within cells to optimize photosynthesis.
They also help control the opening and closing of stomata, thus influencing gas exchange and water regulation.
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Related terms
Phytochromes: Red/far-red light receptors that regulate plant development and circadian rhythms.
Chloroplast Movement: The process by which chloroplasts position themselves within plant cells to maximize photosynthetic efficiency under varying light conditions.
Stomatal Opening: The mechanism through which stomata open to facilitate gas exchange and transpiration in plants.