Aerobic System
Physical activity lasting more than a few minutes requires the presence of oxygen. Oxygen is not immediately abundant to the muscles when we begin exercise; rather, it gradually becomes available as the oxygen-rich blood fillsthe muscle cells. This allows the third energy pathway, called the aerobic pathway to become the predominant supplier of ATP. This process of fuel degradation is sometimes called aerobic metabolism.
The aerobic system can be divided into three main parts:
- aerobic glycolysis – glucose is broken down into pyruvic acid then converted into a specialised enzyme called acetyl-coenzyme A (acetyl-CoA)
- the Krebs cycle – acetyl-CoA enters a series of reactions in which it is broken down to produce AT
- the electron transport system – another series of reactions where hydrogen, leftover from the Krebs cycle, splits into protons and electrons and the electrons undergo more reactions to allow ADP and P to resynthesise to form ATP.Each part plays a significant role in the resynthesis of a large
amount of ATP.
The major fuels for the aerobic system are:
- glucose (from glycogen stored in the muscle tissue or the liver)
- fatty acids (from triglycerides in adipose tissue and blood
- amino acids (from proteins stored in muscles or the liver; but these are not used for energy production to the extent of the two sources
above).
The aerobic system can be divided into three main parts:
- aerobic glycolysis – glucose is broken down into pyruvic acid then converted into a specialised enzyme called acetyl-coenzyme A (acetyl-CoA)
- the Krebs cycle – acetyl-CoA enters a series of reactions in which it is broken down to produce AT
- the electron transport system – another series of reactions where hydrogen, leftover from the Krebs cycle, splits into protons and electrons and the electrons undergo more reactions to allow ADP and P to resynthesise to form ATP.Each part plays a significant role in the resynthesis of a large
amount of ATP.
The major fuels for the aerobic system are:
- glucose (from glycogen stored in the muscle tissue or the liver)
- fatty acids (from triglycerides in adipose tissue and blood
- amino acids (from proteins stored in muscles or the liver; but these are not used for energy production to the extent of the two sources
above).