Photosynthesis uses two main reactants: carbon dioxide (CO2) and water (H2O). Light energy captured by chlorophyll drives the reactions, but it is not listed as a reactant in the overall chemical equation; instead, light energy powers the process that splits water and reduces CO2 to organic molecules. Key points

• Overall reactants: CO2 and H2O. The water is split in the light-dependent reactions, releasing oxygen gas as a byproduct.
• Primary outputs: glucose (a carbohydrate) and oxygen, with ATP and NADPH generated to power carbon fixation in the later steps.
• Context: Photosynthesis occurs in two stages—the light-dependent reactions (which require light) and the Calvin cycle (which synthesizes sugars using the energy carriers ATP and NADPH from the first stage).

If you’d like, I can provide the balanced overall equation and a quick breakdown of the two stages with the main steps and enzymes involved.