Cellular Respiration and the Photosynthesis co-exist as the paired metabolic processes. Photosynthesis utilizes light energy to transform carbon dioxide into glucose, a simple sugar, in two steps, the light dependent and light independent reactions. Oxygen is generated as a by product at the time of photosynthesis. This reaction stores the energy in chemical bonds of the glucose.

Sugar and other carbohydrates are utilized as fuel sources by cells. At the time of process of Aerobic Cellular Respiration, glucose is broken down utilizing the oxygen. This reaction liberates energy that is used to form ATP molecules, the energy carrier molecule of cells. The process also liberates Carbon Dioxide as a by product.