Now for the forward reaction going this way, we see that the reactants are at a higher energy level than the products and that means this is an exothermic reaction. So going this way in the forward direction we have an exothermic reaction and energy is released into the surroundings. Now for the reactants to actually transform into the products, we have to input enough energy. Specifically, we have to input this amount of energy, which is our activation energy, it's the activation barrier. So basically, if we input this amount of energy, the reactants can basically reach the transition state and then convert to the product. And what protein enzymes do, what enzymes do is they basically bind to the reactants in some form or way and they actually lower the activation energy by basically providing a completely different reaction pathway.