According to Campbell, the definition of a catabolic reaction is:
Some metabolic pathways release energy by breaking down complex molecules to simpler compounds. these degradative processes are called catabolic pathways, or breakdown pathways. ... Energy released from downhill reactions of catabolic pathways can be stored and then used to drive uphill reactions of anabolic pathways.
The book also mentions that:
It is important to realize that the breaking of bonds does not release energy; on the contrary, as you will soon see, it requires energy. The phrase "energy stored in bonds" is short-hand for the potential energy that can be released when new bonds are formed after the original bonds breaking, as long as the products are of lower free energy than the reactants.
Can someone help me link these two ideas considering the apparent "contradiction"? How is it that catabolic pathways, which release energy, work on breaking bonds, which require energy? Are catabolic pathways energy-releasing because of the "net" energy difference because the heat required to break bonds exceeds the energy required to break them? And how are those bonds broken? I think the book was attempting to answer my question in that second excerpt, but I could not fully grasp it from their wording. Thank you!