0Enzymes: Temperature, pH, and Specificity
Hands-On Labs, Inc. Version 42-0054-00-01
Lab Report Assistant This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.
Exercise 1: Enzyme Specificity
Observations
Data Table 1: Glucose Concentration
Wells Concentration of Glucose
a
b
c
d
e
Questions
A. What determines a person’s ability to digest lactose?
B. Which of the wells showed a positive result for glucose? Explain the results.
C. Explain why testing for glucose is used to determine the activity of the enzyme lactase.
D. Explain the experimental conditions for the five different wells.
Data Table 2: Presence of glucose in wells indicating lactase activity at various temperatures
Well Time (min) Concentration of Glucose
a 5
10
15
20
b 5
10
15
20
c 5
10
15
20
Exercise 2: Enzymes and Temperature
Observations
Questions:
A. Graph the effect of temperature on the activity of the enzyme lactase.
B. What happens when an enzyme is boiled? Is this effect reversible?
C. Based on your experiment results, what is the optimal temperature for lactase function?
D. Explain what happens as far as the effectiveness of the enzyme at the freezing temperature. Can this effect be overcome when the temperature rises?
Exercise 3: Enzymes and pH
Observations
Data Table 3: Glucose in wells a-d indicates enzyme activity at various pH levels
Well pH Concentration of Glucose
a 3.5
b 5.0
c 6.8
d 11.0
Questions
A. Graph the data placing glucose concentrations on the y-axis and the pH values on the x-axis.
B. What was the effect of pH on the enzyme lactase? Is this true for all enzymes?
