Potato Enzyme Lab honors PDF

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Potato Enzyme Lab Objectives:  Observe the breakdown of hydrogen peroxide toxin by potato’s enzyme catalase.  Determine if temperature and pH affect enzyme effectiveness. Background Information: Some plants such as potato and spinach have very high levels of catalase, an enzyme that works on hydrogen peroxide to yield water and oxygen. Hydrogen peroxide is a toxic chemical that is produced in many organisms during metabolism. Organisms must get rid of this toxin to survive. Catalase can be found in most tissues of the body, along with plant material such as potatoes. Materials: Potato (cubes) Test tubes (2 sets of 3) Test tube rack glass stirring rod

Vinegar (10 ml) Hydrogen Peroxide (60ml) baking soda

Procedure: 1. Take several pieces of cubed potato and put into test tubes. Label 1 set of test tubes: heat, room temperature, cold. Keep the “room temperature” test tube in the test tube rack. Take the “heat” test tube and put into boiling water for 5 minutes. Put “cold” test tube in bowl of ice for at least 5 minutes. 2. Put all three test tubes in test tube rack. Add 10ml of hydrogen peroxide to room temperature test tube first. Observe the reaction and record. If there is catalase present foam should be produced. The foam produced is a result of catalase converting hydrogen peroxide into water and oxygen; the bubbles are filled with this oxygen. The more bubbles produced the faster catalase is carrying out this reaction, or the more catalase present. 3. Next, add 10ml of hydrogen peroxide to the “cold” test tube, record observations. Lastly, add 10ml of hydrogen peroxide to the “heat” test tube. Record your observations. 4. Put several pieces of cubed potato into the second set of test tubes. Label the test tubes: acid, neutral and base. Add a pinch of baking soda to the “base” test tube. Add 10 ml of vinegar to the “acid” test tube. Do not add anything to the “neutral” test tube. Take the glassstirring rod and mash the potato cubes. Let the test tubes sit for 5

minutes. Add 10ml of hydrogen peroxide to each test tube and record your observations. Group members: 1. What test tube is the control group? Why? 2. Formulate an If/then hypothesis. Remember if/then hypothesis always follow the same form of if the ________________(dependent variable) is related to the _______________(independent variable) in ________ way, then given _____(condition) I predict ______________(outcome).

DATA AND OBSERVATIONS

Test Tube

Observations

Analysis questions: 1. Did you support or refute your hypothesis? Why? What data leads you to that conclusion? 2. What did the catalase do? How do you know? 3. What did grinding the potato up do to the rate of reaction? Why did this change the rate? 4. What did cooking the potato do to the rate of reaction? What conclusion can you draw

Conclusion: Briefly summarize the experiment/restate the objective. Restate your hypothesis. Was your hypothesis supported or refuted? Why or why not? Include data in your explanation....