Respiration is an energy producing process but ATP is being used in some steps of this process also. In fact, ATP is used so that some important intermediates could be formed during the process. During respiration, ATP is utilized twice. Once, it is utilized to convert glucose into glucose 6-phosphate. ATP is also utilized to convert fructose 6 - phosphate into fructose 1,6 - biphosphate. Finally, when respiration of one molecule of glucose is complete; there is a net gain of 36 molecules of ATP. It is the net gain of ATP which is more important and which shows that respiration is an energy yielding process.