Question

Why is water present as both reactant and product molecules in the overall equation for photosynthesis?

Answer 1

The reactants for photosynthesis are light energy, water, carbon dioxide and chlorophyll, while the products are glucose (sugar), oxygen and water. The reactant water molecule is taken up from the soil by the roots for splitting and producing oxygen. Water is also a product of photosynthesis. This water is produced from the oxygen atoms in the carbon dioxide molecules. The oxygen molecules released into the atmosphere come exclusively from the original water molecules, not from the carbon dioxide molecules.