Enzyme Action: Catalase Lab
This lab experiment is posted on the Vernier website. Vernier is one of the leading producers of probeware and software for data collection in classrooms and labs. There are several student lab procedures you can download directly from this site, but to access the teacher background information you must purchase the lab book entitle Biology with Vernier. Obviously, this lab is only applicable if your school has access to the Vernier probes. If you have access to Vernier probes, this lab is an excellent way to emphasize this particular course level expectation. Hydrogen peroxide is lethal to cells in high doses, so our cells produce the enzyme catalase in order to break hydrogen peroxide down into water and oxygen. The probes in the lab will be measuring the oxygen output via pressure. The more pressure, the more oxygen produced. This lab has three different variables: 1) concentration of the enzyme; 2) temperature of the environment; and 3) pH of the environment. It is possible to complete one section per class period. The data collection is superb and lends itself well to a formal lab report.
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In this experiment, you will
- Use a computer and Gas Pressure Sensor to measure the production of oxygen gas as hydrogen peroxide is destroyed by the enzyme catalase or peroxidase at various enzyme concentrations.
- Measure and compare the initial rates of reaction for this enzyme when different concentrations of enzyme react with H2O2.
- Measure the production of oxygen gas as hydrogen peroxide is destroyed by the enzyme catalase or peroxidase at various temperatures.
- Measure and compare the initial rates of reaction for the enzyme at each temperature.
- Measure the production of oxygen gas as hydrogen peroxide is destroyed by the enzyme catalase or peroxidase at various pH values.
- Measure and compare the initial rates of reaction for the enzyme at each pH value.
Part I Effect of Enzyme Concentration
- How does changing the concentration of enzyme affect the rate of decomposition of H2O2?
- What do you think will happen to the rate of reaction if the concentration of enzyme is increased to five drops? Predict what the rate would be for 5 drops.
Part II Effect of Temperature
- At what temperature is the rate of enzyme activity the highest? Lowest? Explain.
- How does changing the temperature affect the rate of enzyme activity? Does this follow a pattern you anticipated?
- Why might the enzyme activity decrease at very high temperatures?
Part III Effect of pH
- At what pH is the rate of enzyme activity the highest? Lowest?
- How does changing the pH affect the rate of enzyme activity? Does this follow a pattern you anticipated?
- Different organisms often live in very different habitats. Design a series of experiments to investigate how different types of organisms might affect the rate of enzyme activity.
- Consider testing a plant, an animal, and a protist.
- Presumably, at higher concentrations of H2O2, there is a greater chance that an enzyme molecule might collide with H2O2. If so, the concentration of H2O2 might alter the rate of oxygen production. Design a series of experiments to investigate how differing concentrations of the substrate hydrogen peroxide might affect the rate of enzyme activity.
- Design an experiment to determine the effect of boiling the catalase on the reaction rate.
- Explain how environmental factors affect the rate of enzyme-catalyzed reactions.
- 600 mL beaker
- Vernier computer interface
- enzyme suspension
- four 18 X 150 mm test tubes
- Vernier Gas Pressure Sensor
- 1-hole rubber stopper assembly
- pH buffers
- 10 mL graduated cylinder
- test tube rack
- 250 mL beaker of water
- 3% H2O2
- three dropper pipettes