Inputs in the light reaction of photosynthesis Inputs in the light reaction of photosynthesis Solution Inputs in the light reaction of photosynthesis are Light energy, ADP, Pi, NADP and H2O 2H2O + 2NADP+ + 3ADP + 3Pi O2 + 2NADPH + 3ATP These reactions begin with the absorption of light energy by pigments, and end with the production of stored chemical energy in the form of NADPH and ATP.