Aerobic cellular respiration uses oxygen to produce ATP.
Aerobic metabolism uses oxygen to extract energy from glucose and stores it in a biological molecule called adenosine triphosphate (ATP). ATP is the human body’s source of energy, and the breakdown of ATP molecules releases energy that is used for a variety of biological processes, including the movement of molecules across membranes. Aerobic metabolism is also called aerobic respiration, cellular respiration, and aerobic cellular respiration. Anaerobic metabolism is another form of metabolism, but it takes place without oxygen, but the human body is not designed to sustain anaerobic respiration for a long time, and that causes great stress.
Glucose is broken down for energy in aerobic glycolysis.
The first stage of aerobic metabolism is called glycolysis. Glycolysis occurs in the cytoplasm of the cell. Complex sugars are broken down into glucose by a variety of enzymes, and this glucose is then broken down into two molecules of pyruvic acid, also known as pyruvate. The energy released by this decomposition is stored in two ATP molecules. Glycolysis is unique in that it is the only stage of metabolism that occurs in the cytoplasm and the other two stages occur within the mitochondria.
Aerobic metabolism occurs primarily within the mitochondria.
In the second stage of aerobic metabolism, called the citric acid cycle, the two pyruvate molecules are used to create energy-rich reducing molecules that are used later in the respiration process. Some of these molecules can be converted directly to ATP if necessary, although this is not always the case. Water and carbon dioxide are produced as waste products of this cycle, which is why humans inhale oxygen and exhale carbon dioxide. The citric acid cycle, like glycolysis, produces 2 ATP.
The final stage of aerobic metabolism is called the electron transport chain and takes place in the inner membrane of the mitochondria. In this step, energy-rich molecules derived from the citric acid cycle are used to maintain a positive charge gradient, called the chemiosmotic gradient, which is used to generate many ATP molecules. This step generates most of the ATP from the aerobic metabolism process, creating an average of about 32 ATP molecules. After the electron transport chain has generated ATP, the energy-rich molecules are free to be reused by the citric acid cycle.
Aerobic metabolism generates approximately 36 ATP molecules. Anaerobic respiration generates only about ten percent of that amount. Oxygen use is more important at the end of the electron transport chain as it helps in the chemiosmotic gradient. The existence of an oxygen-dependent metabolism is the reason why mitochondria are commonly known as the engine of the body.