Which of the following best characterizes the role of ATP in cellular metabolism?

• A. The release of free energy during the hydrolysis of ATP heats the surrounding environment.
• B. It is catabolized to carbon dioxide and water.
• C. The DG associated with its hydrolysis is positive.
• D. The charge on the phosphate group of ATP tends to make the molecule very water-soluble.
• E. The free energy released by ATP hydrolysis may be coupled to an endergonic process via the formation of a phosphorylated intermediate.

Answer: (E)

Verified step by step guidance

1. Understand the role of ATP in cellular metabolism: ATP (adenosine triphosphate) is the primary energy carrier in cells. It provides energy for various cellular processes by undergoing hydrolysis.
2. Explore the concept of ATP hydrolysis: ATP hydrolysis involves the breakdown of ATP into ADP (adenosine diphosphate) and an inorganic phosphate (Pi), releasing free energy that can be used by the cell.
3. Consider the coupling of ATP hydrolysis to endergonic processes: In cellular metabolism, the energy released from ATP hydrolysis is often used to drive endergonic reactions, which require an input of energy. This is achieved through the formation of a phosphorylated intermediate.
4. Examine the formation of phosphorylated intermediates: During the coupling process, the phosphate group released from ATP can be transferred to another molecule, creating a phosphorylated intermediate. This intermediate is often more reactive and can participate in subsequent reactions.
5. Recognize the importance of energy coupling: The ability to couple ATP hydrolysis with endergonic processes is crucial for maintaining cellular functions, as it allows cells to perform work and synthesize necessary compounds efficiently.