Question

the two graphs shown here represent a reaction that proceeds without an enzyme (left) and with an enzyme (right). according to the information shown here, what is the most likely role of enzymes in a chemical reaction?
a the enzyme allows the reaction to occur forwards or backward.
b the enzyme reduces the level of product that is made from the original reactants.
c the enzyme reduces the amount of activation energy required for the reaction to proceed.
d the enzyme reduces the number of reactants required to make the same amount of product.

Explanation:

Enzymes are biological catalysts. Catalysts lower the activation energy (the energy required to start a reaction) of a chemical reaction. In the graphs, the red arrow likely points to the activation - energy barrier. Option C is incorrect because enzymes do not change the amount of product (the yield of the reaction) but only the rate at which the product is formed. Option B is incorrect as enzymes do not affect the level of product made from reactants (the equilibrium of the reaction in terms of product - reactant ratio, assuming a reversible reaction). Option D is incorrect because enzymes do not reduce the number of reactants required to make a given amount of product. They just make the reaction (with the same amount of reactants) proceed faster by lowering the activation energy.

Answer:

C. The enzyme reduces the amount of activation energy required for the reaction to proceed.