In 1959, Nobel prize winner Severo Ochoa showed that as many as 38 molecules of ATP could be generated by respiration from a single molecule of glucose.
This means that oxygen respiration can produce 19 times more ATP per molecule of glucose than does fermentation.
ATP has been found in every type of cell ever studied, whether plant, animal, fungal, or bacterial.
However, one detail was troubling and nagged at the chemistry of respiration: the number of ATP molecules produced by each species varied.
Somewhere between 28 and 38 molecules of ATP are formed from a single glucose molecule.
The mitochondria is the only place in the cell where oxygen can be combined with by-products of digestive metabolism to keep the cell full of energy.
Glycolysis begins in the cytosol and pyruvate and is the fork in the road for which one of the fates of pyruvate will enter the mitochondrial matrix.
Here a set of reactions convert pyruvate to acetyl-CoA which starts the Krebs cycle.
Thus, it is the Krebs cycle that is responsible for energy production.
In the electron transport chain in Complex one also referred to as the NADH dehydrogenase complex, the chain removes 2 electrons from NADH and passes them through an iron-sulfur mineral complex to bind to a fat-carrying ubiquinone which is oxidized CoQ10 which will be reduced to ubiquinol resulting in 4 protons (H+) being pumped across the membrane, creating a protein gradient.
This is the primary site within the electron transport chain where electrons leak – producing superoxide free radicals.
This is certainly a complex process, and if not done by the body efficiently, it will result in an energy deficit that is felt by you as feeling fatigued or run down.
This is why it is so important to balance the biochemistry of the body in order for these processes to work efficiently.