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I am going to investigate the effect of pH and temperature on the activity of the enzyme amylase.

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Introduction

Title: Amylase Hypothesis I predict that as the temperature increases, the speed of the reaction will increase. When a particular temperature is reached I believe the rate of reaction will dramatically decrease. I believe this because most chemical reaction happens faster when the temperature is higher. At higher temperatures molecules mover around faster, which makes it easier for them to react together. Usually, a rise of 10OC will double the rate of reaction. This is true for enzymes up to about 40OC. However at 40OC the enzyme begins to be damaged, so the reaction slows down. By 60OC the enzyme is completely denatured. I predict that the same will happen the further away the pH is from pH 7. I believe this because the optimum temperature for most enzymes is about pH 7 therefore the further away from pH 7 (either more alkaline or more acidic) the less affective the enzyme. To investigate the factors affecting the activity of the enzyme Amylase, I will adapt a pilot experiment, which investigates if the enzyme amylase breaks down starch. The pilot experiment was: Method * Pour amylase solution into a test tube to a depth of 2cm. ...read more.

Middle

Due to the enzyme's unique active site it can only convert one kind of substrate molecule into one kind of product. First of all the average time taken for the starch to be digested in each condition was calculated. Temperature(OC) 10 21 32 40 50 55 60 67 80&90 Average Time (min) 9.8 6.7 5.3 5.5 3.5 3.0 3.5 4.5 10 + pH 8 7 6 5 3 2 Average Time (min) 9.5 6.7 4.5 2.8 4.7 9.2 The results were then plotted on a graph (see Graphs 1 & 2) and the points joined together. From graph 1, I can see that as the temperature of the mixture increases, the time taken for the amylase to digest the starch decreases. This happens fastest at 55OC, however if the temperature continues to rise then the time taken for the amylase to digest the starch rapidly increases. By the time 80 OC is reached the amylase does not digest the starch. From graph 2, I can see that as the pH of the mixture increases, the time taken for the amylase to digest the starch decreases. ...read more.

Conclusion

I believe that the experiment was designed well but there were a few problems. The optimum temperature for the amylase was too high. I believe that all the results were skewed because the enzyme was not given enough time at each particular temperature to be fully affected before it was added to the starch. Because of time restraints they were only left in the water bath for 10 minutes before starting the experiment. However, they should have been left in the water bath for about 30 minutes so that the amylase had been completely affected by the temperature before the experiment was started. I decided to conduct the experiment at 10 OC intervals instead of 5 OC because there was not enough time. When the results were collected I plotted them on a rough graph to find the optimum temperature and then conduct the experiment at this temperature to ensure it was the optimum temperature. I also conducted all three experiments for each condition at the same time to save time. Additional work, which could be carried out, is to repeat the experiment using, a wider range of temperatures and pH levels, a range of different starch solution concentrations or using different enzymes such as protease with a protein. ...read more.

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