Photolysis of water

• When light strikes chlorophyll, it loses electrons, and in order to continue absorbing light, the electrons must be replaced. These replacement electrons can come from water molecules that are split using light energy.
• The symbol equation for the photolysis of water is: 2H2O -> 4H+ + 4e- + O2
• The protons produced by photolysis exit the thylakoid space through ATP synthase channels, which are then taken up by NADP electron carriers, causing them to become reduced.
• The reduced NADP and electrons from the chlorophyll will then participate in the light-independent reaction.
• The products of the LDR are put to use in other regions of the plant. The reduced NADP is used as a further source of chemical energy in the plant, whilst the oxygen produced is used in respiration or diffuses out of the plant as a waste product.