Catalase is an enzyme found in plant and animal cells. Hydrogen peroxide is a harmful substance found in cells. Catalase causes hydrogen peroxide to break down into water and oxygen. A student conducted an experiment to determine whether plant and animal cells have the same amount of catalase. She used liver and potato tissues in the experiment. The student followed the following procedure: 1. Label two identical test tubes, 1 and 2. 2. Pour 10 milliliters of hydrogen peroxide solution (1% concentration) into each test tube. 3. Add a small piece of liver tissue to Test Tube 1. 4. Add a small piece of potato tissue to Test Tube 2. 5. Collect the oxygen released from each test tube for 25 seconds. 6. Measure and record the volume of oxygen for each test tube. a) What is the independent and dependent variable? Justify your response. b) Identify two variables from the experimental design that were controlled for in this experiment. c) What did the student not keep constant or control for?

2.

For what type of medical conditions have placebos shown to be effective? For what type of medical conditions have placebos shown not to be effective?

pur-new-sol

Related Questions