How do enzymes affect reaction rates and energy barriers?

Enzymes lower activation energy, increasing reaction rates.

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur. Activation energy is the energy required to break the bonds in the reactants and initiate the reaction. Enzymes achieve this by binding to the reactants, which lowers the activation energy required for the reaction to occur. This reduces the amount of energy needed to start the reaction, making it easier for the reaction to take place.

Enzymes also affect reaction rates by increasing the frequency of successful collisions between reactant molecules. Enzymes do this by bringing the reactants into close proximity and orienting them in a way that makes it easier for them to react. This increases the likelihood of successful collisions, which in turn increases the reaction rate.

Enzymes can also affect the energy barriers of reactions by stabilising the transition state of the reaction. The transition state is the high-energy intermediate state that the reactants must pass through in order to form the products. Enzymes can stabilise this transition state by forming temporary covalent bonds with the reactants, which reduces the energy required to reach the transition state. This makes it easier for the reaction to proceed, and increases the reaction rate.

In summary, enzymes lower activation energy, increase the frequency of successful collisions between reactants, and stabilise the transition state of reactions. These effects all contribute to increasing reaction rates.