What effect does breaking down reactants have on energy?

Breaking down reactants primarily involves a process known as catabolism, where complex molecules are broken down into simpler ones. During this breakdown, the energy that was stored in the chemical bonds of the reactants is released. This is a fundamental concept in biochemistry and metabolism, as the energy released can then be harnessed by the organism to perform work, such as fueling cellular processes or movement.

When bonds between atoms are broken, the potential energy that was held in those bonds is unleashed. This energy is often captured in the form of ATP (adenosine triphosphate), the energy currency of the cell. Therefore, the correct answer indicates that breaking down reactants leads to a release of energy that was previously stored within them. This principle is crucial for understanding how cells metabolize nutrients and utilize energy for various biological functions.