Cellular Respiration Cellular respiration can be described as a chemical process that breaks bonds in food molecules or transforms chemical energy from organic molecules into ATP. - Only 40% of food energy is extracted and used for cellular work where the other 60% leaves in the form of heat energy ATP= Provides chemical energy for cellular work/processes in the cell. Structure= Composed of complex organic molecule called adenosine with a tail of three phosphate groups and a ribose sugar- pentose (ADP+P=ATP) (ADP is a diphosphate with an adenosine) ATP is recycled from ADP and phosphate through cellular respiration, ADP and P are connected to create ATP to be used for cell processes, ATP is used for cellular work and ADP and P are extracted from food molecules to create ATP again.