Photosynthesis is the process by which atmospheric carbon dioxide is assimilated and converted to glucose and oxygen is released. CO2 and H2O are utilised in the process. In the cellular respiration, glucose is broken down to CO2 and energy is released in the form of ATP, which is utilised in performing various metabolic processes. Oxygen is utilised in the process. Energy is stored in the process of photosynthesis, whereas it is released in the process of cellular respiration. The process of cellular respiration and photosynthesis complement each other. These processes help cells to release and store the energy respectively. They are required to keep the atmospheric balance of carbon dioxide and oxygen concentrations.