 Two phosphoanhydride bonds ( those that connect adjacent phosphates ) in an ATP molecule are responsible for the high energy content of this molecule . In the context of biochemical reactions , these anhydride bonds are frequently – and sometimes controversially – referred to as high @-@ energy bonds ( despite the fact it takes energy to break bonds ) . Energy stored in ATP may be released upon hydrolysis of the anhydride bonds . The primary phosphate group on the ATP molecule that is hydrolyzed when energy is needed to drive anabolic reactions is the γ @-@ phosphate group . Located the farthest from the ribose sugar , it has a higher energy of hydrolysis than either the α- or β @-@ phosphate . The bonds formed after hydrolysis – or the phosphorylation of a residue by ATP – are lower in energy than the phosphoanhydride bonds of ATP . During enzyme @-@ catalyzed hydrolysis of ATP or phosphorylation by ATP , the available free energy can be harnessed by a living system to do work . 
