Part 1. Photosynthesis is a means to transform light energy from the sun to stored chemical energy. This is done by converting CO2 that enters into the leaves of a plant with the addition of H2O to form sugar and O2. O2 is released as the by-product of photosynthesis. Sugar is where the chemical energy is stored.
This is the chemical equation of photosynthesis:
6CO2 + 6H2O → C6H12O6 + 6O2