Enzyme Demonstration – Lab #1

SWBIC Educational Resources  >> Activities & Materials  >> Enzyme Unit Plan  >> Lab 1


1 red potato
large test tubes
3% hydrogen peroxide
test tube rack
600 ml beaker


Cut potato into chunks; place chunks into blender along with 1 cup water. Blend till smooth.

Meanwhile, set up two test tubes, one labeled A and the other labeled B. Fill each with 20 ml distilled water and 10 ml hydrogen peroxide. After you have blended the potato as smooth as possible, strain the mixture through the cheesecloth and collect the liquid in the beaker; the pulp can be discarded. Pour about 20 ml of this liquid into test tube B.


  1. What is an enzyme?

  2. How did the addition of the potato solution affect the contents of test tube B?

  3. Why was there no change in test tube A?


The skin of red potatoes contains a high amount of the enzyme catalase. Catalase speeds up the decomposition of hydrogen peroxide to oxygen gas:

H2O2 —————–> H2 +   O2

The evolution of oxygen gas can be observed by the foam produced in test tube B. No foam is produced in test tube A because no catalase is present to speed up the breakdown of hydrogen peroxide.

Developed for SWBIC by John Palmer, Gadsden High School.