Enzyme Experiment Name : Hyo Ji Kim Partners : Shi Wan and Sandy Aim : In this experiment, I would like to determine how the amount of chicken liver affect the speed of catalase reaction. The factors might affect the speed of catalase is the amount of chicken liver. This experiment will be carried out by using different amounts of chicken liver to measure oxygen production in a gas collection cylinder setting. Hypothesis: If larger amount of chicken liver is used, catalase reaction occurs quicker. Therefore, more oxygen gas will be produced. In contrast, if smaller amount of chicken liver is used, catalase reaction occurs slower. Therefore, less oxygen gas will be produced. Variables : • Input Variable : Amounts of Chicken Liver I will change the amounts of chicken liver by measuring it on the electronic balance. In this experiment, I chose to experiment 1g, 4g and 7g of chicken liver in all of the three trials.
• Output Variable : Amount of Oxygen gas generated on different amount of chicken liver I will measure the amount of oxygen gas generated on each of chicken liver weights that has been decided. The generated oxygen gas will be measured using gas collection cylinder. • Control Variable : 1. Amount of Hydrogen peroxide I will keep constant amount of hydrogen peroxide which is 50ml by measuring it in the graduated cornical flask in all trials and all weights of chicken liver. 2. Concentration of Hydrogen peroxide I will keep similar concentration of hydrogen peroxide which is 1% in all trials and all weights of chicken liver. 3. Time to measure oxgen gas observation I will keep the observation time of gas collection constant by using a stopwatch and setting it to 3 minutes observation time in all trials and all weights of chicken liver. Equipments : • Forceps / Tweezers • Scalpel • Petri Dish • 3 x 100ml Cornical flasks • 1 stopwatch • 50ml x 9 (for 3 trials and 3 different weights of chicken liver) = 450ml 1% Hydrogen peroxide • 16g x 3 (for 3 trials) = 48g chicken liver • Disposable dropper • Electronic balance • Gas collection cylinder • Gas collection tube with cork
Diagram : Method : 1. Prepare gas collection tube set up according to the diagram given. The set up includes gas collection cylinder and gas collection tube which is attached to the cork that could be fitted to the cornical flask. 2. Prepare 3 amounts of chicken liver using the electronic balance scale. The weights should be 1g, 4g and 7g. 3. Add 50 ml of 1% Hydrogen peroxide in the cornical flask. 4. Put the measured 1 g chicken liver in the cornical flask. 5. Quickly cork the cornical flask with the gas collection set up. 6. Set 3 minutes in the stopwatch for gas collection time. 7. Record how much oxygen gas was collected in the gas collection cylinder after 3 minutes. 8. Repeat step 3 but using 4g of chicken liver. Do step 4, 5 and 6. 9. Repeat step 3 but using 7g of chicken liver. Do step 4, 5 and 6.
10. Repeat step 1 to 8 for second and third trials. Data Table : Table 1 : Amount of liver verses Amount of Oxygen produced Oxygen gas produced for 3 minutes (cm3) Amount of liver (g) Trial 1 Trial 2 Trial 3 Average 1.0 12.0 13.0 17.0 14.0 4.0 21.0 26.0 31.0 22.7 7.0 32.0 41.0 49.0 40.7 Graph : Graph 1: Amount of Liver vs Amount of Oxgen produced Amount of Oxgen produced (cm3) 50 40 30 20 10 0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Amount of Liver (g) Conclusion : Our groups data is reliable for two reasons. First of all, we had precise measurements of 1g, 4g and 7g. We set the electronic balance as 0g in order to use it and then measured the weights of chicken liver. With tweezers and scarpel, we even could take a very small piece of chicken liver out.
Therefore, we could use exactly 1g, 4g and 7g chicken liver. Furthermore, our group had three trials for investigating with different weights of chicken liver. We repeated the experiment three times and always the same pattern was discovered from the results. Having precise measurements and repeating the experiment helped our group to get more reliable data. Our group’s hypothesis "more liver is used, the more oxygen gas will be generated" was correct. Liver was made up of proteins and thus it worked as enzyme in the catalase reaction. In this experiment, catalse in the chicken liver created bubbles and produced oxygen gas when mixed with hydrogen peroxide. As a result, during enzyme reaction, the more liver was used, the more oxygen gas was generated. In fact, the hypothesis was proved from the results in the data table above. On average, 1g chicken liver produced 14ml oxygen gas. 4g chicken liver generated 22.7ml oxygen gas on average. Most massively, 7g chicken liver created the average of 40.7ml oxygen gas. This data simply showed that the amount of liver affect the amount of oxygen gas produced. Catalase reaction occurred quicker when we used larger amount of chicken liver. As a result, more oxygen gas was produced. In contrast, catalase reaction occurred slower when we used smaller amount of chicken liver. Consequently, less oxygen gas was produced. Therefore, our group made the correct hypothesis.Evaluation : Our group had not done the experiment well for three errors. First of all, we didnt use the accurate amount of 50ml Hydrogen peroxide for each trial. The 100ml cornical flasks we got didnt have the graduation of 50ml, so we estimated 50ml by the middle of the space between 40ml and 60ml. Therefore, the amount of 1% Hydrogen peroxide was not all the same 50ml in each trial. This was the problem because the amount of Hydrogen peroxide would affect to the amount of oxygen gas produced from the liver. When more amount of Hydrogen peroxide was used, it would interrupt liver to generate oxygen gas. Thus, the error of having different amount of 50ml Hydrogen peroxide could affect to the whole experiment. Furthermore, the cornical flasks we had were too big that the cork attached to the gas collection tube couldnt stick. This would be a big problem unless we changed to other shape of cornical flasks because oxygen gas would evaporate to the air. The amount of oxygen gas produced from different amount of chicken liver could be decreased. Therefore, the error of having big cornical flasks would cause a big problem to the experiment. Most importantly, there was a failure of trial which used 10g chicken liver. 10g chicken liver produced great amount of oxygen gas. Finally, a piston went out from the gas collection cylinder despite 3 minutes didn’t pass yet. We couldn’t measure the amount of oxygen gas that 10g chicken liver could generate. Therefore, we should rearrange both 5g and 10g chicken liver to 4g and 7g. Thus, we cut 4g and 7g chicken liver and did the experiment again, which wasted time. As a result, the error of setting 10g chicken liver influenced to the entire experiment. The experiment could improve in two ways. First of all, our group could have 3 gas collection set up for each weight. This would be very clear to see the difference and will make the experiment going faster. Moreover, our group could use already measured chicken liver. This would insure precision in measurements and will make our data more reliable. Furthermore, our grup could get smaller cornical flasks or get bigger cork attached to the gas collection tube. This would keep the oxygen gas
produced from chicken liver, so we could correctly observe the investigation and have the right results. At last, we could get cornical flasks that had 50ml graduation. This would make the amount of Hydrogen peroxide constant, so chicken liver wouldn’t be interrupted to cause catalase reaction and generate oxygen gas. For other experiments related to this investigation, we could change : ‐ The type of liver ‐ The concentration of hydrogen peroxide ‐ The temperature of hydrogen peroxide ‐ The time of collecting oxygen gas.