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In this investigation, I will be finding out which temperature, the enzyme, lipase, works best at. I will do this by looking to see how effective the enzyme is at each of the chosen temperatures.

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Introduction

Enzymes Introduction In this investigation, I will be finding out which temperature, the enzyme, lipase, works best at. I will do this by looking to see how effective the enzyme is at each of the chosen temperatures. Planning To investigate which temperature the lipase works best at I will conduct an experiment using water baths at different temperatures. In the experiment I will also use full fat fresh milk, phenolphthalein and lipase. I have chosen six temperatures to see how long it takes for the solution to turn back to a white colour these are: 0 C, 20 C, 40 C, 60 C, 80 C and 100 C. I will put 2ml of milk and 10 drops of sodium carbonate in a test tube and in another test tube I will put 3ml of phenolphthalein and 2ml of lipase. These will both go in the same water bath although still staying separate. I will then wait for each test tube to heat up to the same temperature as the water bath and then I will pour the phenolphthalein and lipase into the other test tube. The colour of the solution should then turn pink and I will then time how long it takes for the solution to turn back to a white milky colour. Apparatus Method Six water baths were set up to the different temperatures used in the investigation, this was so the experiment could be done using different temperatures. ...read more.

Middle

this is shown at point 1 this will be due to the fact that up until the peak on the graph, as the temperatures rises there will be more energy in each of the fat and lipase particles therefore causing them to move around at a faster rate. The faster the particles will be moving the more collisions there will be. This will lead to more fat particles being broken down in a shorter space of time therefore causing an increasing rate as shown on part 1 of the sketch graph. Part 2 of the sketch is a decline this is through the lipase particles becoming too hot and therefore denaturing into a shape which does not fit into the fat particles therefore not managing to break them down this causes a decreasing rate of the reaction and therefore less fat particles being broken down in a longer period of time. The peak of the graph is where the lipase enzyme will work best. I think this will be a round forty degrees Celsius as this is the closest temperature to the human body temperature. The enzyme will work best at this stage, as they are adapted to working in the human body, which has a temperature of around thirty-seven degrees Celsius. As forty degrees Celsius is the closest temperature to this that I will be testing I believe that the lipase will work best at this temperature. ...read more.

Conclusion

My average result in each case was closest to the median repeat for each temperature therefore proving that my results were accurate. In the graph the accuracy of my results was shown as my graph has a good fit to the expected curve. In the method there are possible sources of error. An example of this is the measurement of the phenolphthalein and the sodium carbonate. These were measured using a pipette and by counting the drops one of the problems that arose is that the drops from the pipette maybe different sizes therefore meaning that a different amount of each substance may have been put in to the test tube each time. Another problem that arose is relating back to an original colour. The end of the reaction was very difficult to differentiate between each time as it was difficult to say whether the original colour had been restored, to defeat this problem in the experiment a control test tube containing just plain milk was used to refer to but it was still difficult to ensure that they were exactly the same colour. To overcome this problem a colorimeter could have been used and this would allow us to match the colours more easily. Another option for the same problem is to use a pH meter, which indicates the exact pH of the solution this could be used by testing the control test tube and the experiment would be over when the control test tube and the test tube containing the experiment have the same pH levels. ...read more.

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