Final answer:
ATP hydrolysis releases energy to drive both endergonic and exergonic reactions, playing a key role in cellular metabolism and functioning as the cell's energy currency.
Step-by-step explanation:
ATP hydrolysis is an exergonic reaction that releases energy, which powers both endergonic and exergonic reactions in cells, and it is indeed the energy source for various cellular processes including catabolism of nutrients.
The hydration of an ATP molecule to ADP and inorganic phosphate (Pi) releases free energy. This energy is critical for metabolic processes, acting as the energy currency within the cell. The AG (free energy change) of this reaction is negative, which implies that ATP hydrolysis is spontaneous under cellular conditions and provides the energy necessary for various cellular functions like muscle contractions, nerve impulse transmission, and active transport such as the sodium-potassium pump operation.
The process of energy coupling uses the energy from ATP hydrolysis to fuel endergonic reactions that would otherwise not occur spontaneously. This coupling is fundamental to the cell's ability to perform work, such as moving substances against their concentration gradients, in the case of the sodium-potassium pump.