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 through its hydrolysis.
2. Recognize the process of ATP hydrolysis: ATP is hydrolyzed to ADP (adenosine diphosphate) and an inorganic phosphate (Pi), releasing energy that can be used by the cell.
3. Identify the concept of coupling: The energy released from ATP hydrolysis is often used to drive endergonic reactions, which require an input of energy. This is achieved by coupling the exergonic hydrolysis of ATP with the endergonic process.
4. Understand phosphorylated intermediates: During coupling, the phosphate group from ATP can be transferred to another molecule, forming a phosphorylated intermediate. This intermediate is often more reactive and can participate in subsequent reactions.
5. Recognize the importance of free energy: The free energy released during ATP hydrolysis is crucial for driving cellular processes. It is not used to heat the environment but rather to perform work within the cell, such as muscle contraction, active transport, and biosynthesis.