Catalase Lab
Directions:
You will create a lab report for this lab. Use the information provided here in your report. Be sure to cite the work of G. Nelson.
Question:
- What effect will decreasing the substrate (H2O2) concentration by 50% have on the reaction rate?
- What effect will decreasing the enzyme (catalase) concentration by 50% have on the reaction rate?
Background:
"A catalyst is a substance that lowers the activation energy required for a chemical reaction, and therefore increases the rate of the reaction without being used up in the process. Catalase is an enzyme, a biological (organic) catalyst. Hydrogen peroxide is the substrate for catalase. Hydrogen peroxide (H2O2) is a poisonous byproduct of metabolism that can damage cells if it is not removed. Catalase is an enzyme that speeds up the breakdown of hydrogen peroxide into H2O and O2."
Source: Genevieve Nelson. Access Excellence Catalase Lab. On-line. © The National Health Museum.
We will be using a potato extract as a source of catalase. You will record the time it takes a catalase-soaked paper disk to rise when placed in H2O2. The disk will rise from the added buoyancy of O2 bubbles clinging to it. We will use this time as a proxy measurement for reaction rate. You will want to have multiple trials.
Hypotheses (predictions):
- Two predictions provided by the student.
Equipment:
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The Generic Procedure for Measuring Catalase Activity:
- Nearly fill a test tube with fresh H2O2 solution.
- Use the tweezers to dip a paper disc in the enzyme solution.
- Place the disc on a paper towel to drain off the excess enzyme solution.
- Drop the disc into the H2O2 solution. The disk should sink to the bottom of the graduate.
- You may have to tap the disc to get it to sink (rinse tweezers after).
- Measure the time it takes the disk to rise to the surface.
Procedures for Creating Catalase and Substrate Dilutions:
Student provided.
Data Tables
Student provided.
Conclusions
Student provided.