ATP hydrolysis releases energy by breaking what kind of bond?

• A. High-energy phosphate bond
• B. Hydrogen bond
• C. Carbon-carbon bond
• D. Peptide bond

Answer: (A)

ATP hydrolysis releases energy when the phosphoanhydride bond linking the terminal phosphate to the rest of the molecule is broken. This bond is called a high-energy phosphate bond because its cleavage yields a large amount of free energy under cellular conditions, which powers many cellular reactions. The energy comes from factors like relief of electrostatic repulsion among the negatively charged phosphate groups, plus greater resonance stabilization of the products (inorganic phosphate and ADP or AMP) and increased system entropy. Hydrogen bonds, carbon–carbon bonds, and peptide bonds are not the bonds being cleaved in this reaction, so they don’t account for the energy released during ATP hydrolysis.