Almost all reactions necessary for life are catalyzed by enzymes. Answer the following questions
about enzymes to improve your understanding.
1. What does it mean that enzymes catalyze chemical reactions?
2. What is an active site?
3. Enzymes work as a ‘lock and key’ mechanism. What does this mean?
4. What molecule does the enzyme lactase break down? Can lactase catalyze any other reaction?
5. Draw a diagram to represent the 4 steps in an enzymatic reaction.
6. What does it mean to denature an enzyme?
7. What conditions can result in denaturing of an enzyme?
8. Look at the graph to the right. What is the optimal (best)
temperature for enzymes to control the rate of
9. Pepsin and trypsin are both enzymes that digest proteins, but one works in the stomach and the other in the small intestines. The pH of the stomach is between 1.5 and 3, and the pH of the small intestine is ~8. Use the graph below to answer the questions.
a. Which enzyme, trypsin or pepsin, digests proteins in the stomach? How did you know?
b. Which enzyme digests proteins in the small intestine? How did you know?