Question

(01.02 mc)
which of the following best describes what happens to an enzyme after it catalyzes a chemical reaction?
○ a its mass decreases since part of the molecule is used up.
○ b it is unchanged and can be used again for the same chemical reaction.
○ c it becomes chemically bonded to the products of the reaction.
○ d its shape changes, giving it different chemical and physical properties.

question 16 (4 points)
(01.02 mc)
which of the following best describes the relationship between the shape of enzymes and the reactions they catalyze?
○ a the shape of an enzyme depends on the reaction that it needs to catalyze.
○ b enzymes with more active sites can catalyze several reactions at once.
○ c the shape of an enzyme determines which reaction it can catalyze.
○ d enzymes change shape after they catalyze a reaction and become waste products.

Explanation:

Enzymes are biological catalysts. Catalysts are substances that speed up a chemical reaction without being consumed or changed in the process. So, after catalyzing a reaction, an enzyme is unchanged and can be used again for the same chemical reaction. For the second question, the lock - and - key model (and induced fit model to some extent) explains enzyme - substrate interaction. The shape of the enzyme's active site (a specific part of the enzyme) is complementary to the shape of the substrate (the molecule on which the enzyme acts). So, the shape of an enzyme determines which reaction it can catalyze.

Answer:

First question: b. It is unchanged and can be used again for the same chemical reaction.
Second question: c. The shape of an enzyme determines which reaction it can catalyze.