And this means that to form a peptide bond we actually have to input a certain amount of energy and that energy comes from the ATP molecules found inside our body. Now the next question is if these products are higher in energy than these reactants here, why exactly do these bonds not spontaneously break inside our body? So why don't the bonds inside the protein holding our amino acids actually break spontaneously? And the answer is because of a high activation energy. So if we take a look at the following reaction going backwards, this here is the activation energy, the barrier energy that is needed, that we must overcome to actually go from the product side to the reactant side. So even though this reaction here, so going from the products to our reactants is thermodynamically favorable, it is not kinetically favorable.