Catalysts Quiz Attempt 1

Which statement best describes how a catalyst can speed up a chemical reaction? The catalyst decreases the activation energy needed. The catalyst increases the concentration of products. The catalyst binds to enzymes to release substrates. The catalyst increases the concentration of reactants.

a. The catalyst decreases the activation energy needed.

Which two substances bind using a lock-and-key mechanism? enzyme and substrate reactant and substrate substrate and product reactant and product

a. enzyme and substrate

If the activation energy required for a chemical reaction were reduced, what would happen to the rate of the reaction? The rate would increase. The rate would decrease. The rate would remain the same. The rate would be zero.

a. The rate would increase.

The lock-and-key mechanism refers to the complementary shapes of an enzyme and a substrate. the attractive forces between an enzyme and a substrate. the ability of an enzyme to lower the activation energy of a reaction. the ability of an enzyme to "unlock" the products of a reaction.

a. the complementary shapes of an enzyme and a substrate.

Which component is released from the active site of an enzyme during a chemical reaction? reactant product substrate protein

b. product

Which statement correctly describes a chemical reaction? Reactants come out of a reaction. Energy is always released. Bonds between atoms break and reform. Products go into a reaction.

c. Bonds between atoms break and reform.

Which statement best describes the amount of catalyst that remains at the end of a reaction? More catalyst is present at the end than at the beginning of the reaction. Less catalyst is present at the end than at the beginning of the reaction. The amount of catalyst is the same at the end as at the beginning of the reaction. The catalyst is consumed by the reaction, so none remains at the end of the reaction.

c. The amount of catalyst is the same at the end as at the beginning of the reaction.

What is a substrate? a molecule that acts as a catalyst a place where the reaction occurs a place on the product where the enzyme fits a reactant that is catalyzed by an enzyme

d. a reactant that is catalyzed by an enzyme

How does a catalyst work? by increasing the temperature of a chemical reaction by decreasing the pressure of a chemical reaction by increasing the concentration of reactants in a reaction by decreasing the activation energy of a reaction

d. by decreasing the activation energy of a reaction

Which is the best definition of activation energy? the energy required to end a chemical reaction the energy required to bind a substrate to an active site the energy required to form or break the bonds of reactant molecules the energy required to re-form bonds in product molecules

c. the energy required to form or break the bonds of reactant molecules