How many electrons, protons and photons are involved in the lysis of water to evolve one molecule of oxygen?
4e–,4H+ and 4 photons
4e–,4H+ and 8 photons
2e–,2H+ and 8 photons
2e–,2H+ and 4 photons
The correct option is B4e–,4H+ and 8 photons Four electrons must be moved through the photosynthetic electron transport pathway to convert two water molecules into one O2 molecule (plus 4 hydrogen ions), and each electron requires two photons (one at each reaction centre) to traverse the pathway. Therefore, the quantum of light required in photosynthesis is 8 photons for one molecule of oxygen to be evolved. 2×2H2O→4H++O2+4e−