Where is ATP produced?

ATP is produced in the mitochondria in three phases – Glycolysis, Krebs or Citric Acid Cycle, and Electron Transport Chain (ETC).  Because of the importance of ATP, the body uses several different systems to produce ATP. All of these systems work together in the same three phases. Digestion of glucose in the intestines initiates the ATP production process. Cells take up the digested glucose and convert it to pyruvate, which travels to the mitochondria of the cell, where the production of ATP occurs. When cells need energy to perform certain tasks. ATP cleaves a phosphate bond releasing the energy stored within and gets converted to ADP. When the cell no longer needs the energy, the cleaved phosphate bond is restored, converting ADP back to ATP. Once ATP is produced, it can be produced and used repeatedly.