Final answer:
Enzymes reduce the activation energy required for a chemical reaction, allowing the reaction to occur more quickly and efficiently, as depicted by lower energy peaks in a reaction coordinate diagram; however, they do not alter the overall free energy of the reaction.
Step-by-step explanation:
The question concerns the energy required to reach the intermediate state with and without an enzyme in a chemical reaction. In the absence of an enzyme, a higher activation energy is needed for a reaction to begin. This is depicted as a higher peak in a reaction coordinate diagram. In the presence of an enzyme, however, the reaction requires a lower activation energy to reach the intermediate state, which is shown as a lower peak in the diagram. Enzymes achieve this by binding to the substrate to form an enzyme-substrate complex, thereby lowering the energy barrier needed for the reaction to proceed. While enzymes alter the activation energy, they do not change the overall free energy of the reaction. Essentially, enzymes accelerate reactions and allow them to occur more efficiently by providing an alternative reaction pathway with a lower activation energy.
The provided figures and explanations demonstrate that enzymes play a crucial role in facilitating biochemical reactions by creating a more energetically favorable environment for the reaction to proceed, which generally leads to a faster reaction rate.