Question

Discovery of Emerson effect showed the existence of

• A. Photorespiration
• B. Light and dark reaction in photosynthesis
• C. Photophosphorylation
• D. Two distinct photochemical reactions

Answer 1

Answer: (D)

Two distinct photochemical reactions

Emerson effect was discovered by Robert Emerson in 1957. He observed that when 700 nm wavelength is used for photosynthesis then it proceeds very slowly, but when light of shorter wavelength (650 nm) is used then it proceeds very fast. It means when higher wavelength of light is simultaneously supplied with shorter wavelength, then rate of photosynthesis increased. So, the discovery of Emerson effect showed the existence of two distinct reaction centres and photochemical reactions. It showed the existence of Photosystems I and II.