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Investigation Into Trypsin Activity

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Introduction

Investigation Into Trypsin Activity Planning Enzymes control the rate of reaction. They are biological catalysts, speeding up reactions in living organisms. Enzymes are specific in that they only speed up one reaction by joining with the matching substrate, and each enzyme works with only one substrate. The enzyme we are using in this investigation is Trypsin and the substrate is Casein. When the enzyme is added to the substrate at the active site (the place where the enzyme and substrate touch) they will fit like a lock and key hence the lock and key theory. Once the enzyme has broken down the substrate, products will be formed and in this case amino acids. This experiment is about finding how long it takes different concentrations of Trypsin to break down casein (the protein in milk). The completion of the reaction is when the mixture turns transparent. Trypsin Casein (protein in milk) insoluble amino acids (soluble) Preliminaries Method: * Obtain the following apparatus: 5 boiling tubes, 1 beaker filled with milk, 1 beaker filled with Trypsin, 1 beaker filled with water, a test tube rack, a stopwatch 3 5cm� syringe and a writing equipment to record results. * To find a suitable volume of milk for the investigation pour five different amounts of milk into a different boiling tube, the highest starting with 5cm� descending to 1cm�. * Before adding 5cm� of Trypsin to all five boiling tubes start the stopwatch, and record how long it takes each mixture to go transparent. ...read more.

Middle

Time taken for mixture to turn Transparent (s) Attempt 1 Attempt 2 Attempt 3 Average 1.0 85 86 85 85 0.8 120 120 115 118 0.6 150 150 150 150 0.5 165 165 165 165 0.4 210 210 210 210 0.2 270 265 265 267 0.0 -- -- -- -- Concentration of Trypsin (%) Rate of Reaction (1/sec) 1.0 0.01176 0.8 0.00678 0.6 0.00400 0.5 0.00303 0.4 0.00190 0.2 0.00075 0.0 -- Analysing On Graph A there is a negative correlation and therefore a negative gradient of 50/0.2 (250), the Best fit line shows this. The trend is as the concentration increases, the time decreases. This is because as the concentration increases there are more enzymes present, as there is a higher concentration Trypsin than to Water, as the concentration increases. This means that more enzymes are more likely and fit together on the active site with the substrates, i.e. the lock and key theory. With more enzyme-substrate complexes being created more products, i.e. amino acids, are formed at a faster rate. The trend agrees with my prediction that as the concentration increases, the rate of reaction increases. This means the time taken for the mixture turn transparent decreases, as there are now more enzyme molecules to link on to the active site, with the same number of substrate molecules. At a high concentration of 1.0% Trypsin the average time was 85 seconds. This shows that more enzyme-substrate complexes were formed. Thus breaking down the substrate (casein) ...read more.

Conclusion

This concentration could have been experimented on a different day with different sized syringes. The trends on both graphs were as predicted in my planning section. Most of my points on both graphs were very close to my best fit line but for a few points on Graph A 0.2%, 0.5% and 0.6%. on Graph B most of my points were on the best fit line excluding the anomaly, which meant the data was very reliable. The readings of the repeats were not identical but were in a five second range, between each set of three readings. This meant that it was a fair test and there were no crtical errors. Even the anomalous results repeats were in a two second range. This showed the experiment was quite accurate. Improvements and further work that could be added to the experiment would boost the reliability and accuracy of the data. This would include broadening the range of concentrations for Trypsin. We only had a beaker of 1% Trypsin and diluted it to get a range of concentrations; however I would suggest the addition of more pure Trypsin including 2-10%.this would improve the reliability of the data and the trends on both graphs. The temperature, of which the experiment was done in, varied as the experiment was done over 2-3 days. To fully control the temperature I suggest a water container or a water bath that kept the temperature constant. The temperature must be below forty degrees otherwise the enzyme would be denatured or even destroyed. This would lead to much more reliable and far precise results, therefore more conclusive graphs would be produced. ?? ?? ?? ?? ...read more.

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