The Respiratory Balance Sheet

It is possible to make calculations of the net gain of ATP for every glucose molecule oxidised, but in reality this can remain only a theoretical exercise. These calculations can be made only on certain assumptions:

• There is a sequential, orderly pathway functioning, with one substrate forming the next, and with glycolysis, the TCA cycle and the ETS pathway following one after another.
• The NADH synthesised in glycolysis is transferred into the mitochondria and undergoes oxidative phosphorylation.
• None of the intermediates in the pathway are utilised to synthesise any other compound.
• Only glucose is being respired, with no other alternative substrates entering the pathway at any of the intermediary stages. …