Download Graph Enzymes and Metabolism

Enzymes and Metabolism
Name: ____________________________
Much of the human digestive process takes place in the stomach and small intestine. Glands secrete enzymes
that break down protein chains by chemical reactions. Two important digestive enzymes for proteins are pepsin
and trypsin. The effect of the pH on the activity of these enzymes can be determined by analyzing the data
below. Plot the data from the data tables on the graph below and then analyze the activity of the two enzymes
to answer the questions. Use two different colors for your lines and label accordingly. Make sure that your
graph has the axes appropriately labeled and has a descriptive title.
Table 1: Activity of Digestive Enzymes Pepsin and Trypsin
pH
0.9
1.5
3.0
5.0
5.1
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pH
4.0
5.0
6.5
7.5
9.0
Activity of Pepsin-% of
maximum
0
65
100
20
0
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Activity of Trypsin-% of
maximum
0
75
100
90
0
Graph 1: ____________________________________________________
Analysis Questions
1. At which pH is pepsin the most active? Trypsin?
2. If pepsin and trypsin had to function together, which pH would produce the highest activity?
3. What do you think would happen if you took an antacid prior to eating a hamburger? Think about this
in terms of what buffers do.
4. The stomach is a highly acidic environment. Once food leaves the stomach, it enters the small intestine,
where it is neutralized by sodium bicarbonate. Where do you think pepsin and trypsin are the most
active individually? Explain.
5. What happens to the enzymes after they have catalyzed their respective reactions under normal
environmental conditions?
6. What would happen to the enzymes if the pH or even temperature of the environment totally caused the
enzyme to “stop” working? Explain in terms of the active site and what is happening to the enzymes
“shape”.