Cellular respiration is the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. It can occur in the presence of oxygen (aerobic) or in the absence of oxygen (anaerobic). Mitochondria, which are organelles found in cells, play a crucial role in cellular respiration. The primary purpose of cellular respiration is to produce ATP, which is the main source of energy for cells. The inputs or reactants of cellular respiration are glucose and oxygen, while the outputs or products are ATP, carbon dioxide, and water. The entire equation of cellular respiration is: glucose + oxygen -> ATP + carbon dioxide + water.