Photosynthesis is the process by which plants make glucose. Light energy is absorbed by chorophyll which is a green substance found in chloroplasts in some plant cells and algae. This light energy is used to convert carbon dioxide from the air and water from the soil into a sugar called glucose. Oxygen is released as a by-product. The process can be summarised using the following equation: Carbon Dioxide + Water ----(LIGHT ENERGY)----> Glucose + Oxygen