Bond Energy and ATP question!

[shetalweapon]

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Hi guys,
I'm a little confused and hope someone can help me out.

If energy must be ADDED to break bonds and enery is RELEASED when bonds are formed, then why does breaking a bond from ATP release heat/energy?

Thanks in advance guys! I appreciate any input!

 

[bubbachuck]

courtesy of http://en.wikipedia.org/wiki/Adenosine_triphosphate:

The system of ATP and water under standard conditions and concentrations is extremely rich in chemical energy; the bond between the second and third phosphate groups is loosely said to be particularly high in energy. Strictly speaking, the bond itself is not high in energy (like all chemical bonds it requires energy to break), but energy is produced when the bond is broken and water is allowed to react with the two products. Thus, energy is produced from the new bonds formed between ADP and water, and between phosphate and water.[4] The net change in enthalpy at Standard Temperature and Pressure of the decomposition of ATP into hydrated ADP and hydrated inorganic phosphate is −20.5 kJ / mole, with a change in free energy of 3.4 kJ/mole.[5] This large release in energy makes the decomposition of ATP in water extremely exergonic, and hence useful as a means for chemically storing energy. The energy is released by cleaving either a phosphate (Pi) or pyrophosphate (PPi) unit from ATP, in hydrated conditions:

ATP + H2O → ADP(hydrated) + Pi(hydrated) + H+(hydrated) ΔG˚ = -30.54 kJ/mol (−7.3 kcal/mol)
ATP + H2O → AMP(hydrated) + PPi(hydrated) + H+(hydrated) ΔG˚ = -45.6 kJ/mol (−10.9 kcal/mol)

(Note the values given for the Gibbs free energy for this reaction are dependent on a number of factors, including overall ionic strength and the presence of alkaline earth metal ions such as Mg2+ and Ca2+. Under typical cellular conditions, ΔG is approximately −50 kJ/mol (−12 kcal/mol).) [6]