ATP (Adenosine triphosphate) is the energy currency in living organisms. It is produced at the end of respiration and is produced in the mitochondria. It is produced during photosynthesis in the leaves (in chloroplast) in autotrophic nutrition. The released energy is utilized by the cells in making the chemical adenosine triphosphate (ATP) in a process of cellular respiration. Since energy is released during the process, it is an exothermic type of reaction. The cells break down the glucose to its original elements, which are carbon dioxide and water.