The electron transport chain of the cellular respiration process produces maximum ATP.
There are three parts of cellular respiration:
Glycolysis, which produces 2 ATP.
Krebs cycle, which does not produce any ATP. It produces only the raw materials for ATP production.
Oxidative phosphorylation, which involves the electron transport chain that produces maximum ATP. It takes one NADH molecule via Channel 1 to produce 2.5 ATP and one FADH2 molecule via channel 2 to produce 1.5 ATP, for a total of 34 ATP.