Almost all chemical reactions that occur in living organisms are catalyzed by enzymes. Many factors in a cell’s environment affect the action of an enzyme. In this investigation, you will design an experiment to determine the effect of temperature on an enzyme-catalyzed reaction. You will complete an entire lab write-up using the CHS LAB REPORT FORMAT.
Fundamental Question
How does temperature affect the rate of an enzyme-catalyzed reaction?
Materials
• Raw liver • Forceps
• Petri dish • Labeling tape and pen
• Dropper pipette • Ice bath
• 0.1% hydrogen peroxide solution • 3 thermometers
• Liver puree • Warm-water bath
• 25-mL graduated cylinder • Clock or watch with second hand
• 5 50-mL beakers • Paper towels
• Filter-paper disks
Part A: Observe the Catalase Reaction
1. Put on apron and safety goggles. Use forceps to place a small piece of raw liver in an open petri dish. Use a dropper pipette to put a drop of hydrogen peroxide solution on the liver. CAUTION: Hydrogen peroxide can be irritating to skin and eyes. If you spill any on yourself or your clothes, wash it off immediately and tell your teacher. Observe what happens. RECORD in notebook. Liver contains the enzyme catalase, which breaks down hydrogen peroxide (H2O2) to water (H2O) and oxygen gas (O2). When hydrogen peroxide is broken down by catalase, bubbles of oxygen gas are released.
2. With your teacher’s guidance, select the proper equipment and technology to measure catalase activity—a filter-paper disk.
3. To measure the activity of catalase, use a graduated cylinder to place 25 mL of hydrogen peroxide solution in a 50-mL beaker.
4. Use forceps to dip a filter-paper disk in liver puree. Place the filter-paper disk on a paper towel for 4 seconds to remove any excess liquid.
5. Use the forceps to place the filter-paper disk at the bottom of the beaker of hydrogen peroxide solution. Observe the filter-paper