Which one among the following is the source of energy in cells ?

Adenosine Triphosphate (ATP) is known as the "energy currency" of the cell. it is the primary molecule used by living organisms to store and transfer energy for various biological processes, including muscle contraction, nerve impulse propagation, and chemical synthesis.

• Mechanism: Energy is stored within the high-energy phosphate bonds of the ATP molecule. When the cell requires energy, the terminal phosphate bond is broken through hydrolysis, converting ATP into ADP (Adenosine Diphosphate) and releasing a significant amount of energy.
• Other Options: While ADP and AMP (Adenosine Monophosphate) are related molecules, they represent lower-energy states. NAD (Nicotinamide Adenine Dinucleotide) is a coenzyme that functions as an electron carrier in metabolic reactions like cellular respiration, rather than being the direct source of cellular energy.