A set of metabolic processes by which cells extract usable energy from nutrients and transfer much of that energy into ATP.
In human cells, cellular respiration primarily involves the breakdown of molecules such as glucose and the transfer of their chemical energy into ATP. It includes glycolysis, the citric acid cycle, and oxidative phosphorylation. When oxygen is available, most ATP from glucose metabolism is produced through processes associated with mitochondria.
Cellular respiration does not mean breathing. Breathing brings oxygen into the body and removes carbon dioxide, while cellular respiration refers to the chemical reactions inside cells that extract and transfer energy.
QUICK FACT
Cellular respiration can occur without oxygen in certain metabolic pathways, but aerobic cellular respiration uses oxygen and produces much more ATP from a molecule of glucose.
COMMONLY CONFUSED WITH
Breathing: Breathing is the physical movement of air into and out of the lungs; cellular respiration is the series of chemical reactions cells use to obtain usable energy.
SEE ALSO
- Metabolism
- Catabolism
- ATP
- Mitochondria
- Glucose
- Metabolic pathway