Question

Oxygen is evolved in photosynthesis during:

• A. Light independent reactions
• B. Light dependent reactions
• C. Calvin cycle
• D. C${}_4$ cycle

Answer 1

The correct option is B Light dependent reactions

The evolution of oxygen during photosynthesis occurs during light dependent reactions. To compensate the electrons lost from PS-II during non-cyclic photophosphorylation, the water splits and it leads to evolution of electrons, protons and oxygen.

Carbon dioxide fixation occurs during light independent reactions and synthesis of sugars takes place.

Calvin cycle and C${}_4$ cycle are pathways of synthesis of glucose.