Ready to step up your enzyme game? Begin by watching the Enzymes video by Mr. Anderson:
Now that you have been introduced to the enzyme catalase, it is time to see catalase in action through this installment of Lab@Home.
In this video, you will observe the enzyme catalase reacting with hydrogen peroxide (the substrate) to produce water and oxygen gas. The hydrogen peroxide is an aqueous solution consisting of 3% H2O2 and 97% H2O. The picture below depicts a balanced chemical equation along with models of the reactant (H2O2) and products (H2O and O2):
For the experiment, 10 mL of H2O2 was pipetted into each of 3 test tubes. Next, 5 g of finely diced potato was added into each test tube. Before being minced, potato #1 was kept at room temperature, potato #2 was baked in an oven for 30 minutes at 450 °F (232 °C), and potato #3 was frozen for 60 minutes at -20 °C. The 5 g of baked potato was kept at room temperature until the experiment started. The 5 g of frozen potato was returned to the freezer until just before the experiment.
If you have access to a potato and hydrogen peroxide, then you can do this lab at home and dazzle your family. You don’t need any fancy equipment, just do your best to keep the experimental conditions similar. If not, watch the video below carefully. Either way, whether you conduct the experiment yourself, or follow along with the video, write up the experiment into a lab report and submit it for up to +40 bonus points in the lab report section of your semester grade. Let me repeat: this is worth +40 bonus points, which means it is not required, but highly encouraged! If you would like to work with a partner, you may as long as it is clear who did which parts of the report and the work is equally shared.
For full credit, the lab report should consist of:
- Title: Potato Catalase Experiment
- Student Name(s) – two students max with work clearly labeled
- Introduction section: Explain the purpose of the lab. Include your understanding of catalase. What was the manipulated variable (what we intentionally changed)? What were the responding variables (what we observed)? What variables were controlled?
- Procedure section: Include a numbered list of every step needed to conduct this experiment. Have a friend or family member review the procedure and attempt to follow it. If they get lost, fill in the missing steps!
- Results section: Include observations of which samples produced oxygen gas bubbles. Record the time it took for the bubbles to reach the top of the tubes. Include the starting and ending temperatures (given in °C). If you are using the data from the experiment in the video, include and explain the picture below:
- Discussion section: Explain why some, but not all, samples produced oxygen gas bubbles. Include the words enzyme, substrate, products, and denatured. Is the reaction exothermic, isothermic, or endothermic? How do you know? Explain the results: how did the manipulated variable affect the responding variables? Why? What were three possible sources of error? Based on what you learned, what would be your next experiment to further your learning?
Need some help setting up your lab report? Click the link and then select File > Make a Copy and get to it!
Return to the Weeks 34-35 – Lactase Persistence post and continue our work for the week.