The same chemical reaction is graphed twice on the activation energy diagram. Examine the activation energy (Eₐ) diagram below. Potential energy is shown on the y-axis, and reaction progress is shown on the x-axis of an activation energy diagram. For the first curve, the initial energy is labeled X, Y. It curves to a peak at the top and then drops below the initial energy level to a final energy state that is labeled with the letter Z. For the second curve, the initial energy is labeled X, Y. It curves to multiple shorter peaks that appear below the original peak of the first curve. The peak drops below the initial energy level to the same final energy state as the first curve. The energy level at the end of the reaction is labeled Z. © Public Domain Explain the role of enzymes that result in the differences seen in the diagram.