ATP function as an energy currency of the living cells. The last two phosphate radicals in ATP are attached by bonds of high transfer potential. The bond between second and third phosphate radicals possess an energy equivalent of 8.15 kcal/mol. Whereas the bond linking the second phosphate radical with the first one has an energy equivalent of 6.5 kcal/mol. On hydrolysis, ATP forms ADP. ATP+H2oADP+H3PO4+Energy.NADH2 is an electron carrier in electron transport chain. In electron transport chain, one NADH2 provides three ATP molecules.