The molecule that is a key source of energy for living organisms is adenosine triphosphate (ATP). ATP serves as the primary energy currency in cells, supplying the necessary energy for various biochemical reactions, including muscle contraction, nerve impulse propagation, and biosynthesis. When ATP is hydrolyzed, it releases energy by breaking the high-energy phosphate bonds, which can be utilized by enzymes and proteins to perform work. The regeneration of ATP from adenosine diphosphate (ADP) is critical for sustaining cellular functions.