Question

Phytochrome is sensitive to

• A. Red light
• B. Far red light
• C. Green light
• D. Both (A) and (B)

Answer 1

The correct option is D Both (A) and (B)

The change in absorbance of phytochromes is caused by the conversion of a photoreceptor from one structural form to another. The red-absorbing form changes to the far-red absorbing form when it absorbs red light (660 nm) and back again when it absorb far red light (730 nm). The phytochrome molecule is the photoreceptor for red light responses. It exists in 2 forms: Pr and Pfr.