Cellular respiration is the process by which cells convert glucose and oxygen into energy in the form of ATP (adenosine triphosphate). This energy is then used for cellular processes and maintaining the body's functions.
The three stages of cellular respiration are glycolysis, the citric acid cycle, and oxidative phosphorylation. In glycolysis, glucose is broken down into pyruvate. In the citric acid cycle, pyruvate is further broken down and carbon dioxide is released. Finally, oxidative phosphorylation uses electron transport to produce ATP.
Cellular respiration takes place in the mitochondria of cells. Mitochondria are known as the "powerhouses" of the cell because they produce most of the cell's energy.
Aerobic respiration requires oxygen, while anaerobic respiration does not. Aerobic respiration produces much more ATP and is the preferred method of respiration for most organisms. Anaerobic respiration produces less ATP and can only sustain cells for a short period of time.
Cellular respiration and photosynthesis are essentially opposite processes. While cellular respiration converts glucose and oxygen into energy, photosynthesis uses sunlight, water, and carbon dioxide to produce glucose and oxygen. Together, these processes maintain the balance of oxygen and carbon dioxide in the Earth's atmosphere.