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An investigation to show the effect of temperature on the mass of casein present in Marvel powdered milk after a time limit of fifteen minutes.

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An investigation to show the effect of temperature on the mass of casein present in Marvel powdered milk after a time limit of fifteen minutes. Introduction: In this investigation, I will be looking at enzymes; how they work and what factors affect them. I have chosen to carry out an experiment that uses a protease; an enzyme that specifically breaks down proteins and this is called "Savinase". Savinase is an enzyme that is frequently used in laundry detergents and it hydrolyses the peptide bonds between the amino acids present in a protein, therefore 'breaking them down'. In my investigation, I will be using this enzyme together with a substrate of casein of which I will obtain from Marvel(tm) powdered milk. I will be using temperature as my variable as I am investigating what effect temperature has on the mass of casein present in my solution after a time limit of fifteen minutes. To give me an accurate reading of how much protein is present I will be using 'Albustix' which are strips coated in an indicator that changes colour depending on the amount of protein present in the solution. Hypothesis: In this experiment, I will be looking to see the effect of increasing the temperature on the mass of casein present after fifteen minutes in a water bath using the enzyme Savinase. I will be using water baths of varying temperatures (from 10�C- 60�C) and testing the amount of protein present with 'Albustix'. I believe that as the temperature is increased from 10�C to 60�C, more of the protein in the solution will be broken down as temperature is a factor that increases the rate of a reaction- more kinetic energy is given to the enzyme and substrate molecules which mean that they collide more frequently, and therefore the reaction is sped up. This can be proved by testing the efficiency of my enzyme in varying temperatures, the enzyme should function best at higher temperatures. ...read more.


The temperature of the water baths will be varied, I will be using temperatures of 10�C, 20�C, 30�C, 40�C, 50�C and 60�C as I feel that these temperatures will provide me with a wide range of results and will hopefully provide a trend that coincides with my hypothesis. However, a water bath's temperature can fluctuate and because of this reason, a thermometer was placed in the bath to monitor the temperature. This thermometer was checked every minute to ensure that the temperature was constant. Bibliography: NAS Molecules and Cells- John Adds, Erica Larkcom, Ruth Miller- pages 33-35 www.ncbe.reading.ac.uk- page 'enzymes for schools'. Diagrams are from- www.schoolscience.co.uk Information on biological washing powders- http://www.lsbu.ac.uk/biology/enztech/detergent.html Method for actual investigation: 1) The first thing to do is to make up the chosen enzyme,Savinase, to the desired concentration. I have chosen 3% and this concentration is obtained by measuring out 3g of powdered enzyme and adding this to 97cm3 of distilled water. A mass balance should be used in order to achieve accurate measurements. The solution should be placed into a beaker. 2) Next, the substrate must be made up from its powdered form into a liquid. This was done by adding distilled water to it. The substrate that should be used is casein which is present in milk. I am using Marvel powdered milk as it is a source of protein, of which my enzyme hydrolyses. The solution should be placed into a beaker. 3) Seven test-tubes should be placed into a test tube rack. These should be marked with what temperature water bath they're going to be placed into using a chinograph pencil. To these test tubes add 5mls of the substrate. 4) To the substrate add 5mls of the enzyme solution apart from one test tube. The test tube containing both the substrate and the enzyme should be added to a water bath of the desired temperature. ...read more.


I then had to observe the beaker of water at all times to ensure that the temperature did not fluctuate and therefore make my experiment an unfair test. When looking at my results, they are as I had expected them to be. However, I would have expected more protein to have been hydrolysed then the amount that actually was. For example, at 60�C, I would have expected to see a trace of protein remaining however, 0.30 grams still remained. At 60�C, the Savinase and powdered milk molecules would have a lot of kinetic energy and therefore a high mass of protein should be hydrolysed. Overall, I feel that my experiment was a success; I acquired a set of results that are as accurate as possible and I feel that I now have evidence to suggest that the change in temperature alters the rate of reaction between an enzyme and a substrate, between the enzyme Savinase and powdered milk molecules .An increase in temperature increases the rate, a decrease lowers the rate. In order to establish more precise results, in a future experiment I could use a more sensitive device to test for the mass of protein present, such as a colorimeter which passes light through the substance to analyse how dense it is. This would detect if there were more or less protein molecules present compared to the control test. I could also use different enzymes belonging to the protease group of enzymes to see whether a specific enzyme is more efficient at hydrolyzing protein at a lower temperature which would reduce the amount of energy needed. This would be useful in cleaning items of clothing that had a protein based stain on them, as the enzyme would possibly function efficiently at a low temperature, therefore preventing excessive energy loss. Another method I could use would be to use different sources of protein or I could extend my experiment further by monitoring the temperature at which the most protein was hydrolysed; therefore finding the optimum temperature of the enzyme. Laura Bailey Candidate Number- 0167 ...read more.

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