Photosynthesis and respiration are chemical reactions that are interrelated and essential for life. Photosynthesis occurs in plants and algae and uses carbon dioxide, water, and sunlight to produce oxygen and energy in the form of glucose. The glucose is then used as fuel for cellular respiration, which takes place in all living cells and uses glucose and oxygen to produce carbon dioxide, water, and energy to power cellular functions. These two processes are vital as they provide organisms with energy and oxygen while removing carbon dioxide from the environment.