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Experiment to investigate the activity of enzyme catalase at different pHs.

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Experiment to investigate the activity of enzyme catalase at different pHs Prediction I predict that a pH of 7 will be the optimum Ph for the reaction and will give off the most bubbles. This is because enzymes have actives sites, which are affected by Ph. The active site fits the substrate allowing the reaction to work at it's best. When there is strong acid or alkali in the solution the active site is denatured changing the shape of the active site so that it is harder for the substrate to fit it, this slows or even stops the reaction. Hydrogen Peroxide Water + Oxygen This is the reaction I am going to investigate. Using different Buffer Solutions- solutions of differing pH values will alter the pH of the reaction. The optimum pH for the reaction will be the one, which produces the most bubbles. The more bubble given off the quicker the rate of reaction. Variables The variables I am going to change will be the pH buffer testing each pH 3 times. ...read more.


* Placed the bung on top of the measuring cylinder with the hydrogen peroxide, mushroom and pH buffer in. * Started the stopwatch * Started counting the bubbles * Stopped counting after 2 minutes * Recorded the results Trial Run Results These are the results I found using two different concentrations: Concentration Bubbles 10% 68 20% 97 As you can see the rate of reaction was much greater using 20% concentration, so this will be the one we will use for our experiments. Results Try 1 Try 2 Try 3 Average PH 2 8 9 7 8 PH 4 27 43 31 34 PH 7 91 101 83 82 PH 9 82 107 92 94 PH 12 1 0 3 1 These are the results of the enzyme catalase reaction with 1g of mushroom. We used hydrogen peroxide with a 20% concentration for the reactions. We put 15 cm of hydrogen peroxide in a test tube with 1g of mushroom and 15cm of ph buffer. ...read more.


Namely the fact different types of mushrooms were used. This may have had major affects on the accuracy of our pH averages. I did not find any anomalous results in my repeats for each pH as the results were consistent with each other so I am inclined to believe the change in mushroom type had not adverse affects on the overall reliability of my experiment. In some places my experimental process was weak. Instead of counting the bubbles given off, to make the experiment more reliable I could have measured the exact volume of the gas given off using a gas syringe. As I have stated my repeats for each pH were close in value. Though they do not support my prediction as pH 9 gave off the most bubbles. My results show a clear trend in enzyme activity and show that pH 9 gave off only marginally more bubbles. Testing all the pH values from 1-12 could extend the experiment. This would give a wider band of results making the experiment more accurate again. This would also confirm the theory further. I could also test different sources of the enzyme catalase e.g. (liver) and see if the pattern was similar. ...read more.

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