Catalase Enzyme Lab
What would happen to your cells if they made a poisonous chemical? You might think they
would die. In fact, your cells are always making poisonous chemicals. They do not die because
your cells use enzymes to break down these poisonous chemicals into harmless substances.
Enzymes are proteins that speed up the rate of reactions that would otherwise happen more
slowly, without being altered by the reaction itself.
You have hundreds of different enzymes in each of your cells. Each one is responsible for one
particular reaction that occurs within the cell. In this lab, you will study an enzyme that is
found in the cells of many living tissues. The name of the enzyme is catalase; it speeds up a
reaction which breaks down hydrogen peroxide (H2O2), a toxic chemical, into two harmless
substances, water and oxygen.
2 H2O2  2H2O + O2
This reaction is important to cells because hydrogen peroxide is produced as a byproduct of
many normal cellular reactions. If the cells did not break down the hydrogen peroxide, they
would be poisoned and die. In this lab, you will study the catalase found in liver cells. Despite
the cells of the liver being dead the enzymes remain intact and active for several weeks if the
tissue remains refrigerated.
Part A: Normal Catalase Reaction
1. Place 2 mL of 3% hydrogen peroxide solution into a clean test tube.
2. Add a small piece of pre-cut liver into the test tube and push it into the hydrogen
peroxide using a stirring rod. Press start on your timer when the liver hits the hydrogen
peroxide and press stop when the reaction has come to an end.
3. Measure the height of the bubbles and record.
4. Feel the temperature of the test tube with your hand. Is the reaction endergonic or
exergonic? Explain how you know. Record your answer in Part A, Question 1.
5. After the reaction has stopped pour off the liquid into a second test tube. What is the
liquid composed of? What do you predict will happen if you add new liver to this liquid?
Record your answer in Part A, Question 2.
6. Add a new piece of pre-cut liver into the test tube. Measure the height of the bubbles
and record.
7. Now add 2 mL of hydrogen peroxide to the liver still in the first test tube. Press start on
your timer when done adding the hydrogen peroxide and press stop when the reaction
has come to an end.
8. Measure the height of the bubbles and record.
Part B: What Tissues Contain Catalase?
1. Place 2 mL of 3% hydrogen peroxide solution into a clean test tube.
2. Add a small piece of potato into the test tube and push it into the hydrogen peroxide
using a stirring rod. Press start on your timer when the potato hits the hydrogen
peroxide and press stop when the reaction has come to an end.
3. Measure the height of the bubbles and record.
4. Repeat these steps for apple.
Part C: The Effect of Temperature on Catalase
1. Place a piece of pre-cut liver into the bottom of a clean test tube and cover it will a small
amount of water. Place the test tube in the boiling water bath for 5 minutes.
2. Remove the test tube from the hot water both and allow it air cool, then pour out the
water.
3. Add 2 mL of hydrogen peroxide. Press start on your timer when done adding the
hydrogen peroxide and press stop when the reaction has come to an end.
4. Measure the height of the bubbles and record.
5. Take two clean test tubes. In one add a piece of pre-cut liver and in the second add 2 mL
of hydrogen peroxide.
6. Place both test tubes into the ice bath for 5 minutes.
7. Remove both test tubes from the ice and add the cold hydrogen peroxide to the cold
liver. Press start on your timer when done adding the hydrogen peroxide and press stop
when the reaction has come to an end.
8. Measure the height of the bubbles and record.
Part D: The Effect of pH on Catalase
1. Add 2 mL of hydrogen peroxide to a clean test tube. Then add 5 drops of acetic acid into
the test tube.
2. Add a small piece of pre-cut liver into the test tube and push it into the hydrogen
peroxide using a stirring rod. Press start on your timer when the liver hits the hydrogen
peroxide and press stop when the reaction has come to an end.
3. Measure the height of the bubbles and record.
4. Add 2 mL of hydrogen peroxide to a clean test tube. Then add 5 drops of sodium
bicarbonate into the test tube.
5. Add a small piece of pre-cut liver into the test tube and push it into the hydrogen
peroxide using a stirring rod. Press start on your timer when the liver hits the hydrogen
peroxide and press stop when the reaction has come to an end.
6. Measure the height of the bubbles and record.
Catalase Enzyme Lab
Part A: Normal Catalase Reaction
1. What gas is being released to create the bubbles?
2. Is the reaction endergonic or exergonic? Explain how
you know.
3. What is the liquid composed of? What do you predict
will happen if you add new liver to this liquid?
Catalase Reactions
Substance
Time of
Reaction (sec)
Normal
Reaction
Old H2O2,
New Liver
New H2O2,
Old Liver
Height of
Bubbles (cm)
4. Explain your observed results when you added new liver to the old hydrogen peroxide. Why did you see these
results?
5. Based on your results for with old liver and new hydrogen peroxide, is catalase reusable? Explain your answer.
Part B: What Tissues Contain Catalase?
1. Based on your data, which tissues contain catalase?
2. Which tissue contains the most catalase? Support your
answer with data.
Part C: The Effect of Temperature on Catalase
1. What is the effect of boiling your liver on the functioning
of catalase? Support your answer with data.
Catalase Reaction in Different Types of Tissues
Substance Time of
Height of
Reaction (sec) Bubbles (cm)
Liver
Potato
Apple
Catalase Reaction in Different Temperatures
Substance
Time of
Height of
Reaction (sec) Bubbles (cm)
Ice Bath
Room
Temperature
Boiling Bath
2. What effect does placing your liver on ice have on the
functioning of catalase? Support your answer with data.
Part D: The Effect of pH on Catalase
1. What is the effect of acid on the functioning of catalase?
Support your answer with data.
2. What is the effect of a base on the functioning of
catalase? Support your answer with data.
Catalase Reaction with Different pH
pH
Time of
Height of
Reaction (sec) Bubbles (cm)
Acid
(acetic acid)
Neutral
(part A)
Base (sodium
bicarbonate)
Part E: Further Analysis
1. Identify the following parts from the lab:
a. Enzyme:
b. Substrate:
c. Products:
2. Design your own experiment as an extensions from what you learned from this lab activity. This is essentially a
further study. This must include:
a. Causal Question:
b. Hypothesis Statement:
c. Independent Variable:
d. Dependent Variable:
e. Constants:
f.
Brief Summary of Experimental Procedures:
g. Expected Results with Explanation (hint: this should include a graph):