Oxygen is the final acceptor of electrons in the electron transport chain. Without oxygen, the electron transport chain becomes jammed with electrons. Consequently, NAD cannot be produced, thereby causing glycolysis to produce lactic acid instead of pyruvate, which is a necessary component of the Krebs Cycle. Thus, the Krebs cycle is heavily dependent on oxygen, deeming it an aerobic process, Dr Sircus writes.
We can literally force mitochondria to become active again and use the Krebs Cycle for energy if we ram enough oxygen into the cells. This process, called Anti-Inflammatory Oxygen Therapy, rockets oxygen into cancer cells so they stop being cancerous (anaerobic) and regain apoptosis, their programmable cell death. If you put enough oxygen into a cancer cell it will turn on the Krebs Cycle (the mitochondria) and this reignites the program for cell death.