Name(s): _______________________________________________ Date: ____________ Block: _______
Measuring the Rate of the Catalase Reaction under Different Conditions.
Hydrogen peroxide (H2O2) is a common but poisonous byproduct of cellular metabolism, but H2O2
does not accumulate in cells because it is broken down to harmless water and oxygen gas. The
decomposition of the hydrogen peroxide is mediated by catalase, an enzyme present in most cells.
The equation for the reaction is: H2O2 __(Catalase)_---> H2O + O2
In this lab activity, you will be using yeast catalase, but you could also use catalase from potatoes,
carrots, plant leaves, chicken liver, or steak….to name just a few of the many places where you can
find catalase.
Pre-Lab Question:
1. What factors are you aware of that might increase or decrease the activity of enzymes? List as
many as possible below:
A.) Creating a baseline:
In this portion of the lab, you will first observe the activity of catalase and discover the baseline rate
of the reaction.
Set up and general procedure:
1. Get the required materials:
4 cups
4 disks of filter paper
1 beaker of catalase solution
1 paper towel
1 pair of forceps
1 beaker of hydrogen peroxide substrate
1-20mL graduated cylinder
1 timer
2.
3.
4.
5.
6.
Put on your safety goggles.
Measure 20mL of substrate (H2O2) with the graduated cylinder and pour it into each cup.
Take a single, disk of filter paper, and using forceps, dip the paper into the catalase solution.
Blot on a paper towel for 3 seconds.
Using forceps, put the filter paper at the bottom of one of your substrate cups. Start timer
immediately and time how long, in seconds, it takes for the filter to float to the top of the
hydrogen peroxide substrate. Record your results in the table below.
7. Repeat 3 more times.
8. Get the average of those trials, expressed in seconds.
Baseline Catalase Results/Data:
Trial 1
Trial 2
Trial 3
Trial 4
Average
B.) Design an Experiment: You and your research partners will design your own experiment to alter
the activity of the catalase. You will present the results of your experiment on a mini-poster.
Background: Remember that enzymes work best under certain physiological (normal, healthy body)
conditions. Your body works best within a certain range of pH, temperature, salt concentrations, etc.
In fact, remember that one of the characteristics of living things is the ability to maintain a constant
internal environment, or homeostasis. One of the reasons for this is because enzymes, which carry
out most of the chemical reactions in your body, work best in a certain range of these factors. Review
pages 51, 53, and 54 in your text to see how enzymes can be impacted by different conditions.
Procedure:
1. Brainstorm ideas about conditions you could use (within the confines of a block of time in our
classroom) to change enzyme activity and record these below:
2. Design your experiment below. You will want to perform your experiment more then once to
prove that you can replicate it. Check with your teacher when you have a workable idea.
Title
Hypothesis
Independent Variable
(IV)
Levels of IV:
Dependent Variable
(DV)
Measurement of DV:
Control Group
Constants (4)
Experimental Design
(How the lab will be
performed)
Approval __________
Experimental Catalase Results/Data:
Trial 1
Trial 2
Trial 3
Trial 4
Average