[Campbell Biology P.200] Which statement accurately describes the energy release from ATP hy... | Practice Question

Which statement accurately describes the energy release from ATP hydrolysis or related concepts, according to the provided text?

  • A: Under typical cellular conditions, ATP hydrolysis releases more free energy (ΔG is about -13 kcal/mol) than under standard conditions (ΔG = -7.3 kcal/mol).
  • B: The term 'high-energy phosphate bonds' accurately describes the unusually strong nature of the bonds between phosphate groups in ATP.
  • C: The release of energy during ATP hydrolysis primarily comes from the breaking of the strong phosphate bonds themselves.
  • D: The actual ΔG for ATP hydrolysis is always -7.3 kcal/mol, irrespective of cellular conditions.

Explanation

The text clarifies that while the standard ΔG for ATP hydrolysis is -7.3 kcal/mol, under typical cellular conditions, it's about -13 kcal/mol, primarily due to differing reactant and product concentrations. It also emphasizes that the energy comes from the chemical change to a lower free energy state, not from unusually strong phosphate bonds.