Biology Lab: Investigating the Properties of Enzymes
Name: ____________________________
ACTIVITY 1: ARE ENZYMES SPECIFIC?
DATA TABLE: Activity 1 (Specificity of Enzymes)
Test Tube
Description of Results with Liver
Homogenate
Description of Results with pure
Catalase (optional)
A: distilled water
B: hydrogen peroxide
C: acetic acid
D: carbonic acid
ANALYSIS
1. Which substances appeared to react with the liver homogenate?
2.
The formula for hydrogen peroxide is H2O2. What are the breakdown products?
3.
What kind of biological molecule is an enzyme?
4.
Describe all four levels of the structure of an enzyme.
5.
How do you account for the differences in the reactions with liver homogenate and the reactions with pure catalase.
ACTIVITY 2: ARE ENZYMES REUSABLE?
DATA TABLE: Activity 2 (Reusability of Enzymes)
Time for
Reaction Letter
complete
reaction (Trail 1)
Time for
complete
reaction (Trial 2)
Comparative Description of Reactions
A: liver piece + peroxide
B: new liver + old peroxide
C: old liver + new peroxide
ANALYSIS
1. Which substance is reusable – the substrate or the enzyme from the liver? Support your answer with evidence.
2.
In part B, what is the “old peroxide?”
ACTIVITY 3: HOW DOES TEMPERATURE AFFECT ENZYME FUNCTION?
DATA TABLE: Activity 3 (Temperature and Enzyme Action)
Test Tube
Time for Complete
Time for Complete
Reaction (Trial 1)
Reactions (Trial 2)
Comparative Description of Reactions
A: liver on ice
B: liver room temp.
C: liver boiled
ANALYSIS
1. What is the relationship between temperature and enzyme activity? Use evidence from your experiments to
support your statement.
2.
What happens to enzyme molecules in extreme temperatures?
3.
Were any of your results surprising? Explain.
4.
What might happen to the human being if a fever gets too high?
ACTIVITY 4: HOW DO CHANGES IN Ph AFFECT ENZYME FUNCTION?
DATA TABLE: Activity 4 (pH and Enzyme Activity)
Test Tube
pH
Time for Complete
Reaction (Trial 1)
Time for Complete
Reaction (Trial 2)
Comparative Description of Reactions
A: 3 drops HCl
B: no acid/no base
C: 3 drops NaOH
ANALYSIS
1. What is the relationship between pH and enzyme activity?
2.
Stomach enzymes work best at a pH of 2, how might a pH of 4 in the stomach affect digestion?
CONCLUSION
 Write a clear, well-supported paragraph describing everything you have learned about
enzymes in this lab activity. USE A SEPARATE SHEET OF PAPER.