What are the reactants and products of photosynthesis?

The reactants of photosynthesis are water, light and carbon dioxide, while the products are oxygen and sugars. Cellular respiration occurs in direct synchronicity with this process, using the products of photosynthesis as its reactants and producing its reactants.

Photosynthesis occurs in most plant life but may differ in some. Algae and related organic life perform a differentiated process which leads to similar results: the breakdown of carbon dioxide and the production of oxygen. It is a relatively simple process at its core.

1. Absorbing light
The first part of the process of photosynthesis occurs when energy from radiant light is absorbed into proteins where chlorophyll is contained inside chloroplasts. These proteins occur in large numbers in most plants. They begin to break down this energy into a form usable by the plant.
2. Repurposing the energy
Water drawn in from the ground and contained in the plant's makeup is stripped of its electrons during the reaction. This produces pure oxygen gas, which is then disseminated from the plant. Other substances are created within the plant, most importantly adenosine triphosphate or ATP, the basic unit of energy used by most cells for sustenance.
3. The Calvin Cycle
Independent of light, glucose and other simple sugars form within the plant as a byproduct of it taking in carbon dioxide and the ATP-dependent process of reducing and stripping it of many of its component parts. This process is directly integral in creating Earth's breathable atmosphere and maintaining a habitable state.