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Investigating the effect of Enzyme Concentration on the Rate of Reaction.

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Investigating the effect of Enzyme Concentration on the Rate of Reaction By Jas Singh 10D Catalase is an enzyme, found in our cells, which speeds up the breakdown of the toxic chemical hydrogen peroxide into oxygen and water. The aim of this practical is to investigate the effect of changing the concentration of catalase on the speed of breakdown. Hypothesis: I believe that the rate of reaction will increase when the catalase concentration is increased. This is because as the concentration of catalase in the solution increases, the more liver cells there will be and so more oxygen bubbles will be produced forcing the paper to rise to the surface faster. This shows that the reaction has occurred faster, and therefore proves that when the catalase concentration was increased, the reaction took place faster. Here is an equation to what I believe will happen: 2H202 O2 + 2H20 Here is how I think the graph will look like: Method: (ON SHEET.) Results: Concentration (g/l) Measurement 1 (s) Measurement 2 (s) Measurement 3 (s) Average (s) 0 7.29 6.23 12.09 8.54 1 39.86 53.98 39.88 44.56 2 30.51 23.74 25.16 26.47 3 18.76 14.63 14.02 15.80 4 23.76 10.71 8.08 14.18 5 9.23 8.65 8.65 8.84 Conclusion: From my results, I conclude that as the concentration of the catalase was increased, the rate of the reaction also increased. ...read more.


Evaluation: I believe my results were fairly reliable, and give a good solid basis to work out my conclusions from. I can say this because as although I did manage to gather a few anomalous results, my averages matched a familiar pattern that I had come to expect it to be similar to. Thus, I can say that my results were reliable and I could work out a successful conclusion from them. As I tested each concentration three times I believe my results would now give a reliable average which I can work from, and that I can trust. By testing each concentration three times, I could now gather an average result. If I for example had only tested each concentration one, then if it happened to be an anomalous result then I would not know, and would have to trust the result even if it was completely wrong. But by doing three results I could identify (if any) the anomalous results, and gather an average that is more likely to be accurate. However there were some faults with my experiment. The first one is the fact that between readings I did not remember to wipe clean my forceps - which could have a negative effect on the readings. Although sometimes I did remember other times I failed to do so. This means that some of my results could be wrong as the old concentration would still be on the forceps, and ruin what I thought to be for example to be 3g/l concentration of catalase and turn it into a 3.5g/l concentration of catalase. ...read more.


Another way these results could have occurred was if the paper had got stuck to the edge, and I have explained this earlier in the evaluation. To make the results more reliable, there are a few other things I could have done. Firstly, I could have experimented with higher concentrations, and seen what the effect was. By doing this I could see whether my assumption of the curve on the graph levelling off was true or not. Second of all, I could have simply done more repeats to make my average for each concentration more accurate. To extend my investigation, I could see whether or not it was actually oxygen being given off during the reaction. How do we know that it is oxygen? To test this, I would trap some of the bubbles given off and put a glowing splint into the oxygen. If it lit up the splint, then oxygen is present. Also, I could test to see whether or not catalase is actually an enzyme, for again how are we to know? To test this, I would heat (and by doing this, denature) what I thought was the enzyme, and repeat the experiment. If the reaction failed to take place or took place extremely slower, then I would know that the denatured substance was an enzyme, as we know that by denaturing an enzyme by heating it beyond its capacity makes the enzyme stop working. ...read more.

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