The process of respiration takes place in a stepwise manner including steps like glycolysis, TCA cycle, ETS, and oxidative phosphorylation. During respiration, the production of ATP also in each phase takes place in a stepwise manner. The products formed in one step of respiration becomes the substrate of the other pathway. Various molecules produced during respiration are involved in other biochemical processes also. Different respiratory substrates enter and withdraw from the pathway on necessity. The ATP also gets utilized wherever required and the rate of reactions of enzymes are also controlled. Therefore, the stepwise release of energy makes the system more efficient in extracting as well as storing energy.