Question

Explain the process photolysis. In the process of photolysis what is the role of 4 electrons and why are they necessary?

Answer 1

Photolysis is a chemical reaction where a chemical compound is broken down by photons. ​It happens during the light reaction of photosynthesis. A photon strikes an electron in the chlorophyll molecule and the electron is passed down through a chain where its energy is utilised. Photolysis therefore takes electrons from water and uses them to replace the lost electron in the chlorophyll. This gives rise to an oxygen molecule and two hydrogen ions. The former pairs with another oxygen forming O₂ which then leaves the plant and the hydrogen ions bond with the electron and NADP⁺ to form NADPH.