Amy Brown Science: FREE LAB! Catalase - An Enzyme Common to Both Plants and Animals

We all have our favorite labs, and this enzyme lab is one of my very favorites. I love this lab because my students come away with a much better understanding of how enzymes do their important jobs within cells. Students love this lab because ... well just look at the picture to the left.

What concepts are covered/reinforced?

1. Enzymes speed up the rate of biological chemical reactions.

2. The same enzymes are found in both plant and animal cells.

3. Enzymes are highly specific for the reaction they catalyze.

4. Enzymes carry out their functions more efficiently than catalysts.

5. Enzymes can be denatured by excessive heat.

Introduction: Catalase is an enzyme that is commonly found in plant and animal tissues. The function of the enzyme catalase is to break down the chemical hydrogen peroxide inside living cells. Hydrogen peroxide (H₂O₂) is a highly active chemical, often used for bleaching.

Within cells, hydrogen peroxide is thought to be formed continually as an end product of biochemical reactions such as cellular respiration. Because it is toxic, or poisonous, it would soon kill the cell if it were not removed or broken down immediately. Therefore, the catalase found in living cells protects the cell by breaking down or digesting this poisonous hydrogen peroxide into water and oxygen.

Manganese dioxide is a catalyst. Catalysts are similar to enzymes in that they speed up chemical reactions, but they are not specific for just one reaction.

Materials needed:

Fresh plant and animal tissue (Potato and Liver)
Boiled animal tissue (Liver)
3% hydrogen peroxide
Manganese dioxide
Test tubes and test tube rack
Sand
Mortar and pestle

Catalase is an enzyme that is found in all eukaryotic cells. This lab will work using any fresh and living tissue. I always use liver as a source of animal cells that contain catalase, and potatoes as a source of plant cells that contain catalase. I purchase the liver frozen at the grocery store. When thawed, it works perfect! Often I will also use a yeast solution to show that fungal cells contain the same enzyme.