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How Temperature Affects the Rate of Reaction of an Enzyme

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How Temperature Affects the Rate of Reaction Of an Enzyme Aim: To investigate the effect of temperature on the breakdown of starch by amylase. Introduction: Description of enzymes: They are proteins. They are biological catalysts - they speed up the rate of chemical reactions. They can be re-used. They help to build up and break down molecules. They are specific in their job. And Enzymes can be affected by: pH Temperature Enzyme concentration Substrate concentrate In the experiment that will be carried out, temperature will be the factor that is going to be put on the enzyme. We will be seeing how long it takes the reaction to begin, and rate of reaction activity. A rise in temperature increases the rate of most chemical reactions, a fall in temperature slows them down (especially reactions taking place inside the body). In many cases a rise of 10 Celsius will double the rate of reaction in a cell. This is equally true for enzyme controlled reactions, but above 50 Celsius the enzymes, being proteins, are denatured and completely stop working. One way to test whether a substance is an enzyme is to heat it to boiling point. If it can still carry out its reactions after this, it cannot be an enzyme. This technique is used as a "control" in enzyme experiments, and this is what we will use. Enzymes are biological catalysts made up from protein. ...read more.


Preliminary Work: The purpose of the preliminary work is to make sure that the actual experiment goes well and our results are accurate. The concentration of the enzyme amylase has to be changed to fit the experiment. If it is too concentrated the starch will be digested too quickly and to time the reaction with a stopwatch will be impossible - and any timings made will be very inaccurate because of the slow human reaction time. But then again, if the enzyme concentration is too low then the reaction will take far too much time, and not a practical experiment to do in a short period of time. For the experiment we will be doing, the enzyme concentration will be 1%, this will make the reaction not too fast and not too slow either. Room temperature is also an issue here. The optimum (the point at which it is at its best) temperature of amylase is around 37 Celsius e.g. body temperature. So for the preliminary experiment taking place we will use the temperatures: 20, 30, 40, 50, and 60 degrees...the reaction time will be taken down. This will help us to see whether our real experiment temperatures will be of interest and use. Method: Equipment List For this experiment you will need: * 5 Test Tubes * Test Tube Rack * Amylase (enzyme) ...read more.


This is because the molecules of the enzyme move faster and faster thus causing the rate of enzyme-substrate collisions to increase. We know that the rate of reaction doubles every 10�C. The temperature rises to such a degree that the enzyme becomes denatured. This is because the molecules of the enzyme vibrate so violently that they break their weak bonds holding the structure of the enzyme together. As shown in the graph, the perfect temperature for the majority of enzymes is 37�C. For this reason, our body temperature is 37�C Evaluation : I think this experiment was quite accurate in finding an answer to our aim. On the other hand many aspects of what was carried out may be improved e.g. the reaction time of a human. The main problem with this experiment was that you could not tell the exact time that the starch had been digested by the amylase enzyme. It was very hard to tell when the liquid had gone wholly clear - when there is no longer starch present. Also there is a persons reaction time, which makes the test not as accurate as it could be. It takes around 0.2 seconds to react to the change in temperature and this makes the timing on the stopwatch imprecise. This should be taken into consideration. ?? ?? ?? ?? Ollie Williams C10 ...read more.

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