[Campbell Biology P.893] Which of the following statements about phytochrome and its role in... | Practice Question

Which of the following statements about phytochrome and its role in light reception during de-etiolation is most accurate?

  • A: Phytochrome, like most plant receptors, is embedded in the plasma membrane.
  • B: Phytochrome is activated by light, leading to the inhibition of de-etiolation.
  • C: Phytochrome is a type of photoreceptor located in the cytoplasm that detects light signals.
  • D: De-etiolation only occurs when light levels are very high, not low.

Explanation

The 'Reception' section clearly states that phytochrome, unlike most receptors built into the plasma membrane, is located in the cytoplasm and is the receptor involved in de-etiolation. It is activated by light to initiate the de-etiolation response. The 'Transduction' section also notes that de-etiolation can be triggered by extremely low levels of light.