The synthesis of atp by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of

It is an example of coupling an exogenic reaction to an endogenic reaction.

Explanation:

The endergonic reaction is typically being pushed by coupling it to strongly exergonic reaction. This is in most cases via shared intermediates. Most chemical reactions are endergonic in nature. In other word, the are not spontaneous (i.e ΔG>0). Energy must also be applied externally to initiate the reactions. The reactions can also be coupled to exergonic reactions (with  ΔG<0) to initiate them through a process known as share intermediate. Because Gibbs Energy can be summed up (i.e is a state function), the combined  ΔG  of the coupled reaction will be thermodynamically favorable.  The decomposition of calcium carbonate is a typical example.