This simple investigation can be completed using materials easily obtained from stores. In a series of tests, students observe how the enzyme catalase breaks down hydrogen peroxide into oxygen and water. Catalase is found in living tissues, but a good reaction can be observed when using chicken livers. The bubbling of the peroxide serves as a measure for how quickly the reaction takes place. Students observe the reaction in livers and in other tissues, like potato and yeast and make observations about whether enzymes are reusable. Students then determine how temperature and pH affects reaction rates by placing the liver in different water baths and adding acidic and basic solutions.
Each section requires students to gather data then complete a CER chart (claim, evidence, reasoning) to answer a guiding question.
Finally, students develop their own experiment to test the effects of lactose on milk sugar. This test can also be performed in the lab or as a demo by using benedict’s solution or glucose food test trips.
Grade Level: 11-12 | *Time Required: 60-75 minutes
*Most of the data collection can be completed in a 50 minute class time, with the next class period for discussion and analysis
HS-LS1-1 Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells