Catalase Enzyme Lab
Name: ____________________________________
Biology 6.0
Date: ____________________
Period: _____
PRELAB:
1.
2.
3.
4.
Write the objective of the experiment.
Write a procedure summary. You may include diagrams/drawings.
Create data tables for Procedure A and B.
Answer the following questions:
a. What is a catalyst?
b. Catalysts increase / decrease the rate of the reaction without being used up. Explain.
c. What is a substrate?
d. Identify three factors that affect/influence enzyme activity.
e. In your lab notebook, rewrite the equation and identify the reactants, the products and the enzyme in
the reaction by writing R, P or E over the substances in the reaction.
catalase
2 H 2O2 
2 H 2O  O2
Introduction to catalase and hydrogen peroxide: Some cells in your body can produce hydrogen peroxide
(H2O2) to help fight infections. Hydrogen peroxide is one of many chemicals that can help cells at low levels
and harm them at high levels. The level of hydrogen peroxide (H2O2) in a cell must be controlled. Hydrogen
peroxide can break down into water (H2O) and oxygen gas (O2). An enzyme called CATALASE helps speed
up this reaction. Catalase is a biological (organic) catalyst. Hydrogen peroxide is the substrate for catalase.
catalase
2 H 2O2 
2 H 2O  O2
The schematic model below shows how an enzyme like catalase works to break down a molecule like hydrogen
peroxide into smaller molecules. Label the following: Catalase, H2O2, H2O, and O2
PROCEDURE:
A. What is the effect of pH on Catalase Activity?
1. Add approximately 2 mL of hydrogen peroxide to each of 5 clean test tubes.
Tube 1 – add 4 drops of HCl
Tube 2 – 1 drop of HCl and 3 drops of water
Tube 3 – 4 drops of water
Tube 4 – 1 drop of NaOH / 3 drops of water
Tube 5 – add 4 drops of NaOH
2. Record the pH of each test tube by using the pH paper. Do not drop pH paper into the test tube!
3. Now add a piece of liver to each of the test tubes and record how much of a reaction is occurring. Try to do
it all at the same time, so you can easily compare. Rate the reaction on a scale of 0 to 5 where 0 is no
reaction and 5 is an extreme reaction.
4. Clean test tubes. Do not put liver in the sink. Be sure to throw ALL solids away in the trash can.
B. What is the effect of temperature on Catalase Activity?
1. Put a small piece of liver into the bottom of a clean test tube (test tube 1) and cover it with a small amount
of water. Place this test tube into a boiling water bath for 5 minutes.
a. After five minutes, remove the test tube from the boiling water bath.
b. Allow it cool in the test tube rack for 4 minutes.
c. Drain the water from the test tube (not the liver).
d. Add 2 mL of hydrogen peroxide.
e. Observe the reaction and rate level of activity.
2. While test tube 1 is in the boiling water bath, put a small piece of liver into 2 clean test tubes (test tube 2 &
test tube 3). Put 2 mL hydrogen peroxide into 2 other test tubes (test tube 4 & test tube 5).
a. Put one test tube of liver (test tube 2) & one of hydrogen peroxide (test tube 4) in an ice bath for 3
minutes.
b. Place the other set (test tube 3 & test tube 5) in a warm water bath (not boiling) for 3 minutes.
c. After three minutes, pour the hydrogen peroxide from test tube 4 into test tube 2. Observe the
reaction and rate level of activity.
d. Pour the hydrogen peroxide from test tube 5 into test tube 3. Observe the reaction and rate level of
activity.
Observations and Analysis Questions:
1. What effect does boiling have on an enzyme?
2. What happens to an enzyme (protein) that has lost its active conformation?
3. Hydrogen peroxide can undergo the chemical reaction WITHOUT the use of catalase. All it needs is a little
bit of energy to proceed to product. This process will just occur at a slower rate than with the catalase
present. Explain why companies that make hydrogen peroxide need to store the solution in the dark bottle.
4. Under which conditions (pH and temperature) does the catalase enzyme work the best? (Examine your
data from Part A and B to answer the question.)
5. List 2 errors that could have occurred in the lab. Do not use human error as a source of error. Be specific
and describe how it could affect the objective of the lab.