Procedure:

After preparing and filtering a red potato, (as previously described) pour approximately 20 ml of the liquid into each of five test tubes, labeled A-E. The five test tubes should be placed in water baths at or near the following temperatures:

1. 5 degrees Celsius
2. 20 degrees Celsius
3. 37 degrees Celsius
4. 65 degrees Celsius
5. 98 degrees Celsius

Now, set up five more test tubes, labeled A-E, in a test tube rack; to each, add 20 ml H₂O₂.

After each of the first five test tubes — containing the enzyme — have sat at their temperatures for at least ten minutes, dump their contents into the second set of test tubes. Make sure you dump the enzyme from A into the other A, B into B, C into C, etc.

After a minute or two, use a ruler to measure the height of the foam produced. Record these amounts.

Analysis:

1. At which temperature was the enzyme most active? (Which one produced the most foam?)
2. At which temperature was the enzyme least active?
3. Construct a line or bar graph, temperature (x-axis) vs. foam height (y-axis).
4. What does your graph say about enzyme activity? Be specific as to temperatures.

Conclusion:

Are enzymes equally effective at all temperatures? Explain your answer.

Developed for SWBIC by John Palmer, Gadsden High School.