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The effect of temperature on enzymes.

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Plan The effect of temperature on enzymes Research Enzymes are proteins that control important biological processes. In the human body, enzymes are used to control the break down of food and control reactions which make products like fats, carbohydrates, proteins and DNA. Enzymes can also control the rate of which chemical substances are built up. Chemical compounds are made up of smaller units called molecules. Each enzyme has its own complicated shape; it can only react with one type of molecule called its substrate. The enzyme's shape must fit into this substrate's shape exactly (a bit like a key). If anything changes this fit, it will alter how well the enzyme works. When enzyme and substrate molecules meet, they can react. In solution, molecules move around freely. If the substrate is the correct shape for the enzyme, they will meet, if it's the wrong shape then they collide. If the temperature is cold, the molecules move slowly which means that they take longer to meet, so the reaction is slowed down. If the temperature is higher than 40oc, the proteins in the enzymes become denatured; this means that the shape of its molecule has been changed so it no longer fits its substrate. ...read more.


Time taken to break down starch (min) 0 20 40 The only variable that will be changed on each experiment is the temperature. Other variables are using different amounts of starch and amylase for each test, and doing the experiment in different ways. There are 6 different temperatures that the experiment will be done at each temperature will be tested 3 times to get an average. The experiment will be done as a group; I will only do the experiment at one temperature. Results These are the results we got as a class: Temperature (0c) Time taken to change (min) Average time taken to change (min) Rate of reaction/time 0 15.5, N/c at 20, 17, N/c at 20, 17 2 N/c at 20, others average at 16.5 0.06 20 9.5, 11, 10.5 7.2 0.1 30 4, 10, 7.5 7.2 0.14 40 5.5, 4, 6.5 5 0.2 50 5.0, 6, 4 5 0.2 60 7, 9.5, 6, 5, 5 6.5 0.15 80 N/c, N/c, N/c at 20 N/c at 20 100 N/c, N/c at 20 N/c at 20 Obtaining evidence I am going to observe how long it takes starch to be broken down by amylase at different temperatures and the rate of reaction against temperature. ...read more.


I also thought that as soon as it got to 60oc the enzymes would denature and not react at all but that was when the started to denature; the reaction slowed down at 60oc but the temperature had to get even higher for them to completely denature. The reason that the enzymes denatured at a higher temperature than predicted was that the enzymes we used were manufactured (we used starch and amylase) so they can stand a higher temperature. 40oc is close to the average human body temperature which means enzymes inside us are usually working at their fastest speed all the time. Evaluation Because different groups within the class achieved similar results, we can assume that the class results were accurate, reliable and suitable. Our results also correspond to scientifically proven experiments and textbooks. An improvement that could be made is to make an extension to the experiment and make it even more accurate by finding out the optimum temperature; we know that it is around 40 0c. If we had more time we would do the experiment at every 0c from 35oc - 45oc. Doing this would find out exactly when the reaction is at its fastest. Clare Apps 10A ...read more.

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