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An Experiment to investigate the affect different temperatures have on the rate of an enzyme controlled reaction. In this case the reaction between Starch and Diastase to form Maltose.

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Introduction

An Experiment to investigate the affect different temperatures have on the rate of an enzyme controlled reaction. In this case the reaction between Starch and Diastase to form Maltose. Research This experiment will test the affect temperature has on the rate of an enzyme controlled reaction. In this experiment the enzyme is Diastase, the substrate is Starch and the product which is produced is Maltose. The equation for what is happening in this experiment is- Diastase Starch Maltose The prediction for the results of the experiment is that as the temperature increases, so too does the rate of reaction. However this prediction is rather vague so for a more scientific explanation the theory behind the function of enzymes needs to be looked at and how temperature affects their functions and structures Firstly, how enzymes work. They can work in two ways, the first of which is the lock and key system. This is that enzymes are specific and that generally any one enzyme will only work on one substrate. This is because only one substrate will fit exactly into the active site of the enzyme. Therefore that enzyme will not break down any other substrates. It has the name lock and key because only one key will fit into a lock to open the door. The other way that enzymes work is induced fit, which is where the substrate may not fit exactly into the active site, so the enzyme changes the shape of the active site slightly. ...read more.

Middle

Variables The independent variable for this experiment is the temperature at which the solutions are getting tested; these are the temperatures which have been mentioned before. As a result of this the dependant variable is the level of starch in the solution, as the amount of starch produced depends on what temperature the enzyme-substrate solution is kept at. For the experiment to be fair there are some factors, which need to remain the same, which are- * The colorimeter- the same machine needs to be used to allow for a margin of error. If different machines are used they may have different margins or error which could cause the results to become inaccurate. * Time- if the time that it takes for the initial sample of the solution to be taken varies the first and subsequent results will be inaccurate. Therefor it is essential that the first sample be taken almost straight away. The time intervals at which the samples are taken need to be the same for each experiment I.E. every minute, on the minute. * Enzyme (Diastase)- if different volumes of Diastase were used in the experiment the results would change completely. This is because if there is more enzyme molecules added to a solution the rate of reaction increases, as there is a greater chance of collisions between enzyme and substrate molecules. ...read more.

Conclusion

This may not seem like a big difference but it would be expected that all of the first readings would be almost exactly the same. This could be improved by having all of the appropriate equipment ready before mixing the solution and by making sure that the solution is mixed in the same way each time. I.E. pouring one into the other at the same rate and with the same force each time so that the enzymes mix in equally. Also when measuring volumes of enzyme, substrate and iodine use the appropriate syringe needs to be used so as to use it the least amount of times to measure out a volume. So if measuring out 3cm� don't use the small syringe (1cm�) use the 5cm� syringe and measure upto 3cm�. This way there are fewer opportunities for bad measuring as only one measurement is made rather than three. In the same way if measuring small volumes such as 0.5cm� don't use a big syringe where guesswork is needed, use the smallest syringe possible, without it being too small The colorimeter will have a slight margin of error so by using the same machine for each temperature that margin becomes irrelevant. Also each curette will either have two stripy sides or a V etched into one side. Ideally every curette should be the same kind, otherwise some results could end up being false. Therefore by using all of curettes the same all results should be true. Rachel French 1.20 1 ...read more.

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