In the presence of oxygen, the three-carbon compound pyruvate can be catabolized (broken down) in the citric acid cycle. First, however, the pyruvate 1. loses a carbon, which is given off as a molecule of CO2, 2. is oxidized to form a two-carbon compound called acetate, and 3. is bonded to coenzyme A. These three steps result in the formation of

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.