Question

question
which of the following statements about enzymes are true?
select all that apply:

enzymes increase reaction rates by lowering the energy of the products.

enzymes increase the rate at which products are created by preventing reactions from running backwards.

enzymes increase reaction rates by lowering the activation energy of a reaction.

enzymes increase reaction rates by interacting with the substrate molecules to facilitate the reaction, for example by contorting them to facilitate bond - breakage or orienting them to favor bond formation.

Explanation:

• Enzymes work by lowering the activation energy ($E_a$) of a reaction. The activation energy is the energy barrier that reactants must overcome to form products. By lowering $E_a$, more reactant molecules have sufficient energy to undergo the reaction, thus increasing the reaction rate. So, the statement "Enzymes increase reaction rates by lowering the activation energy of a reaction" is correct.
• Enzymes interact with substrate molecules. They can bind to substrates and induce conformational changes (contort them) that make it easier for bonds in the substrate to break (bond - breakage) or orient substrates in a way that favors bond formation between reactants. This interaction helps in facilitating the reaction and increasing the reaction rate. So, the statement "Enzymes increase reaction rates by interacting with the substrate molecules to facilitate the reaction, for example by contorting them to facilitate bond - breakage or orienting them to favor bond formation" is correct.
• Enzymes do not lower the energy of the products. The energy of the products is determined by the nature of the chemical reaction and the products themselves, not by the enzyme. So, the statement "Enzymes increase reaction rates by lowering the energy of the products" is incorrect.
• Enzymes do not prevent reactions from running backwards. In fact, many enzymatic reactions are reversible. Enzymes catalyze both the forward and reverse reactions (depending on the concentration of reactants and products). So, the statement "Enzymes increase the rate at which products are created by preventing reactions from running backwards" is incorrect.

Answer:

C. Enzymes increase reaction rates by lowering the activation energy of a reaction.
D. Enzymes increase reaction rates by interacting with the substrate molecules to facilitate the reaction, for example by contorting them to facilitate bond - breakage or orienting them to favor bond formation.