Question

Which of the following do not evolve $O_2$?

• A. green algae
• B. blue-green algae
• C. autotrophic plants
• D. photosynthetic bacteria

Answer 1

Answer: (D)

photosynthetic bacteria

Answer 2

Photosynthetic bacteria are of 2 types - phototrophs and chemotrophs . Phototrophs carry out photoprepare their food using chemicals from surrounding medium. Photosynthetic bacteria shows only cyclic photophosporylation where splitting (photolysis) of water does not take place. Hence, $O_{2}$ is not released.