Enzyme Catalase Lab

Christi Barr Block 4 23 October 2009

Enzyme Catalysts Lab Aspect 1 The purpose of this lab is to compare the results of different sources of catalysts on the decomposition of hydrogen peroxide and the pressure change in each source. The independent variable is the time the hydrogen peroxide has been exposed to the catalyst. The dependent variable is the pressure in the Erlenmeyer flask. The control is the initial reading of pressure. Hypothesis Knowing that a catalyst helps break down hydrogen peroxide, I predict that all the different sources of catalysts will all be approximately the same and produce the same pressure. Aspect 2, 3 Materials • Erlenmeyer flask • Disposable pipettes • Blender • Electric Scale • Pears • Apples • Potatoes

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Yeast Hydrogen Peroxide LabQuest Gas Pressure Sensor Electric Timer Sugar Beaker

Procedure 1. Blend apples in blender and then measure them out into three 10 gram portions. 2. Put one of the 10 gram portions into the Erlenmeyer flask. 3. Before adding the hydrogen peroxide, use the gas pressure sensor to measure the initial pressure in the flask and record. 4. Add 10 mL of hydrogen peroxide to the flask and quickly put the stopper on. 5. Start a stopwatch and after 45 seconds, record the pressure measured in the flask. 6. Repeat this for two more trials. 7. Repeat steps 1-6 with the potatoes and pears. 8. To activate the yeast, you must first have 250 mL of water. Then microwave for 25 seconds so the water is approximately 120-130 degrees Fahrenheit. Add 1.25 oz pack of rapid rise yeast and a pinch of sugar and stir. Then wait 5 minutes. 9. Repeat steps 1-6 with the yeast, minus the blending part.

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Christi Barr Block 4 23 October 2009 Aspect 4 Pressure Change in Different Sources Apple Yeast Pear Trial # Initial Final Initial Final Initial Final Pressure Pressure Pressure Pressure Pressure Pressure (kPa) (kPa) (kPa) (kPa) (kPa) (kPa) 1 98.66 99.21 99.18 107.60 98.76 100.2 2 99.7 100.53 98.77 109.50 99.33 101.42 3 99.12 100.95 99.70 107.48 99.40 99.6 Uncertainty: + or – 0.01 kPa

Potato Initial Pressure (kPa) 100.60 99.68 99.81

Final Pressure (kPa) 109.8 108.51 108.76

Aspect 5 Percent Change in Pressure Apple Yeast Pear Potato Trial 1 0.56% 8.55% 1.46% 8.85% Trial 2 0.82% 10.86% 2.10% 8.86% Trial 3 1.85% 7.80% 0.20% 8.97% Average 1.08% 9.07% 1.25% 8.89% Percent Change in Pressure= [(Final Pressure – Initial Pressure)/ (Initial Pressure)] x 100 Aspect 6

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Christi Barr Block 4 23 October 2009 This graph shows the percent change in pressure in the Erlenmeyer flask for each different catalyst and the three separate trials. From the graph, it is much easier to see which catalyst performed the best. Aspect 7 The data proved that I was incorrect with my hypothesis. I claimed that each substance would all be about the same in effectiveness, when clearly the potato and the yeast acted as much better catalysts than the pear and apple did. This is shown by calculating the percent change in pressure of each catalyst as it is a more accurate measure because in the trials each flask started at a different initial pressure. Because the yeast and the potato produced much higher results, it can be concluded that they have more active sites available for the hydrogen peroxide than the pear and apple and therefore work better and faster. Aspect 8 An error that we encountered during this experiment was that the gas pressure sensor at one point became loose and let gas leak out. We fixed this as soon as we realized, however we were unsure if the data from the pear was affected by this. If the sensor was loose during the pear trials, then it may actually be a good catalyst for hydrogen peroxide and our data would be wrong. I don’t believe the yeast was affected at all, because the results were similar to those of the previous day when we experimented with yeast. With that being said, the apples must not have been affected and we fixed it before we began the potato trials. So the only catalyst that may have been affected by this is the pear. Aspect 9 This lab could be improved by making sure each substance is blended up completely. There were some clumps present in the apples, pears and potatoes which could have possibly skewed the results. Application Questions 1. Give three examples and explanations of how enzymes are used in commercial industries. Bromelain is an enzyme that is used to assist in meat tenderizing that can be found in many pineapple plants. It is in the form of a powder and is put on uncooked meat. Once on the meat, the enzyme enters the meat and causes it to become tender because it helps digest proteins. Cellulase is an enzyme used for processing of coffee. This enzymes works to hydrolyze the cellulose that is found in the coffee bean. Since humans cannot digest cellulose, this process is a necessity to allow us to use the bean and make it into the liquid drink of coffee. Catalase is used in contact lens solutions. These solutions contain catalase so that when put on the contact lens, hydrogen peroxide is decomposed before it is used again. This ensures proper eye hygiene and helps avoid any infection in the eye due to dirty contact lenses.

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Christi Barr Block 4 23 October 2009

2. What is lymphatic filariasis? What do diagnostic tests and vaccine development for lymphatic filariasis have to do with enzymes? (http://medind.nic.in/iaf/t06/i1/iaft06i1p1.pdf) Lymphatic filariasis is a parasitic disease that is caused by thread-like worms that are found in the lymph system, which helps to fight infection and maintain the body’s fluid balance. This disease is spread most commonly by infected mosquitoes. When an infected mosquito bites a person, the worms enter the person’s blood and they become infected. By studying the parasite that causes this disease, researches have discovered enzymes present. Finding this out can help to find a way to inhibit the enzyme’s function so that the disease cannot be spread to humans anymore. 3. How is the catalase enzyme used in cheese production? Catalase is used as an alternative for pasteurization. During pasteurization, some enzymes in a cheese are destroyed. However, some cheeses need to keep those natural enzymes for better quality and taste. Because of this, hydrogen peroxide is added to the cheese to kill any bacteria. Catalase breaks up the hydrogen peroxide and produces water and oxygen, making the cheese safe to eat. 4. What is a PKU test? Who gets it and why? A PKU test is a test to determine if a newborn baby has the enzyme phenylalanine in their body. Phenylalanine helps a baby grow and develop normally. Without this enzyme, the baby can experience brain damage and seizures because it is needed to be broken down into tyrosine. This test is done quickly after birth because phenylalanine can build up very quickly and can cause permanent damage early on.

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