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Experiment to investigate the effect of temperature on enzyme activity

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5/2/02 Experiment to investigate the effect of temperature on enzyme activity Aim The effect of temperature on enzyme activity can be tested in different ways using different enzymes. In this experiment we will be testing the effect of temperature on the activity of Rennilase in the clotting of milk. We will test the time it takes for the milk to clot with this enzyme at different temperatures. Background Information * Enzymes are biological catalysts. * The way enzymes work can be described as the lock and key theory * Enzymes are affected by concentration * Enzymes are affected by PH * Enzymes are affected by temperature 1) Enzymes are Biological Catalysts * Enzymes speed up chemical reactions without changing them (making them a catalyst as this is what a catalyst does). * Reactions that build up larger molecules are called Anabolic reactions. * Reactions that break larger molecules to smaller molecules are called catabolic reactions. 2) The way enzymes work can be described as the lock and key theory * An enzyme provides a place for a reaction to take place. This is called the active site. * The molecule that is going to react is called a substrate molecule. It fits exactly into the active site (hence the lock and key theory the active site is the lock and the substrate molecule the key). * The enzyme then tweaks the substrate molecule so that they form a product. ...read more.


Diagram Safety Safety glasses were worn throughout the experiment to protect our eyes from the rennilase and other substances. Lab coats were worn also to protect us from rennilase as it can digest protein and therefore could be irritable to our skin. If our skin came into contact with rennilase it was washed off immediately. Method 1) Water baths for the temperatures 30,40 and 50�C were prepared. 2) For 0�C ice was placed in one of the large beakers. 3) For 60 and 70�C water of those temperatures were placed in the two other beakers. 4) All of these baths had their temperatures checked and maintained through out the experiment. 5) 6 test tubes were placed in a test tube rack. 6) 1cm� of rennilase was added to 3 of them. 7) 9cm� of milk was added to the other 3. 8) All six test tubes were placed in the beaker containing ice and the temperatures of the milk and rennilase monitored. 9) When the temperatures of the contents in the 6 test tubes reached the temperature of the water in the water bath, the contents of the 3 test tubes containing milk were added to the 3 test tubes containing rennilase and a timer was started. 10) The contents of the test tubes were observed and when the milk clotted the timer was stopped and the time it took for the milk to clot was recorded. ...read more.


This means that the accuracy of the times recorded may have varied. If I was doing the experiment again I would make sure that only one person was assessing this. Limitations If I could repeat the experiment I would give myself a lot more time. I would do this because it was difficult to monitor the results from several sections of the experiment running at the same time. If there had been more time the problem of subjective judgement would have been reduced because one person could obtain all the results. There were insufficient stop watches to monitor each sample. There were insufficient water baths as there were not ones for 0�C, 60�C and 70�C. Further research If I had unlimited time I would investigate the following because I believe they may have an effect on the reaction time: * Types of milk. * PH -Buffer solutions to make different acidities of the medium. Rennilase works in the stomach, which has a PH of about 2. Where as in this experiment the medium in which the rennilase was working had a PH of 7. I would investigate the effect of PH on rennilase. Anomaly In this experiment we had to repeat one of the results for 50�C because the rennilase denatured before we mixed it with milk and so no clotting took place. This confirms that while the reaction rate was maximum at 50�C it is not the optimum temperature. ...read more.

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