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An Investigation into factors affecting the rate of breakdown of sucrose by the enzyme sucrase

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An Investigation into factors affecting the rate of breakdown of sucrose by the enzyme sucrase Plan I am going to investigate the factors affecting the rate of the breakdown of sucrose by the enzyme sucrase. Sucrose is a complex sugar, which is stored and transferred around plants. However, the sucrose cannot be used to provide energy until it is broken down into 2 simple sugars, glucose and fructose. The enzyme sucrase, a biological catalyst which speeds up the rates of reaction, is used to break down the sucrose, the substrate, to form glucose and fructose, the products. There are 4 main factors which affect the rate at which an enzyme works - the enzyme concentration, the substrate concentration, the pH of the solution the enzyme is working in, and the temperature of the environment in which the enzyme is working. I have chosen to investigate temperature and its effect on the rate of breakdown of sucrose by the enzyme sucrase. I predict that the rate of breakdown of sucrose by the enzyme sucrase, will increase with temperature up to a certain point, after which the rate of breakdown will decrease. I think that the rate of breakdown will increase with increasing temperature, in reference to the collision theory: "If the temperature at which a reaction is taking place is increased, then the rate of reaction will also increase. ...read more.


Therefore, I modified my plan and recorded the time taken for the reaction between sucrose and sucrase, using the following temperatures (�C): 10, 20, 30, 35, 40, 45, 50, 60. I also said that I would repeat the experiment 3 times, but I only repeated it twice because I did not have enough time. I was not able to use a buffer solution because there was not one available for my use. Therefore I was not able to use any, as I said I would in my plan, and I had no way of ensuring that the pH was always constant. Here is a table showing my results: Temperature (�C) Time(s) 1 Time(s) 2 Average Time(s) Rate of Reaction (1/t)x1000 10 195 210 203 4.9 20 113 75 94 10.6 30 63 67 65 15.4 35 26 42 34 29.4 40 49 17 33 30.3 45 44 37 41 24.4 50 45 56 51 19.6 60 no result no result no result no result When I refer to time on my results table, I mean the time the sucrase took to break down the sucrose. Rate of reaction is calculated by 1 divided by the time taken for the reaction. I have multiplied these values that I got for rate of reaction, by 1000, so that the figures I get are more workable. ...read more.


If it was blue, the reaction was complete. However, this was not a very good method because the change in colour of the clinistix, from red to blue, is a gradual process, so it was difficult to tell to what degree of blueness I should note the time of the reaction at. Therefore, at different temperatures, I may have accidentally assumed the reaction over, when the Clinistix had got to a different degree of blueness, so my results would not be very reliable. If I could do the experiment again, I would try and use an indicator which is more specific, so that there is no doubt when the reaction is fully finished. Another problem was that there was no way of ensuring that the pH during the experiment was constant. This may have made the experiment even more inaccurate, because the pH was different at different times at different times. If I could do the experiment again, I would use a buffer solution to keep the pH constant. Overall, I think the results of the experiment are quite good, considering the number of flaws there were in the method. However, I think it would be very interesting to do the experiment again, adapting it in the ways that I have mentioned, because I feel that I may manage to get results that agree with the Q10 theory, and which are more reliable. Faizal Patel 6/06/01 - 1 - ...read more.

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