Question

Which of the following are mechanisms by which enzymes lower the energy of activation for a particular reaction? Click all that apply.

The enzyme's active site may provide a template upon which substrates can come together in the proper orientation for a reaction to occur between them.

The enzyme may stretch its substrate(s) toward their transition-state form, stressing and bending critical bonds that must be broken during the reaction.

The enzyme decreases the free energy in the reactants, thereby decreasing the energy of activation as well.

The enzyme increases the free energy in the reactants, thereby decreasing the energy of activation.

The enzyme's active site may provide a microenvironment that is more conducive to the reaction taking place (e.g., a pH that differs from the pH in the cytosol).

The enzyme may participate directly in the reaction - e.g., by forming a temporary covalent bond with one or more of the substrates.

Answer 1

Enzymes lower the activation energy by providing an active site for substrates, distorting substrate bonds, creating an optimal microenvironment, and temporarily forming covalent bonds, without changing the overall free energy of reactants or products.

Step-by-step explanation:

Enzymes are biological catalysts that lower the activation energy of a reaction through several mechanisms. One of the ways enzymes lower the activation energy is by providing an active site that serves as a template for substrates to come together in the correct orientation for a reaction. Furthermore, an enzyme might stress and bend the substrates, distorting critical bonds to facilitate their breaking. These distortions bring the substrates closer to their transition-state form, thereby lowering the activation energy. Another mechanism involves enzymes creating a unique microenvironment within the active site, such as a specific pH level that is optimal for the reaction. Lastly, enzymes may form temporary covalent bonds with the substrates, altering the reaction pathway and reducing the energy barrier. However, enzymes do not alter the overall free energy of the reactants or the products; they only make it easier for the reaction to proceed.