NOTE! The trypsin solution may be reused for 30 C and 40 C because the enzymes will not be denatured.
Results
Class results
Reciprocal calculations
My results:
1 / 479 = 0.002
1 / 337 = 0.003
1 / 125 = 0.008
1 / 102 = 0.010
Class average results:
1 / 536 = 0.002
1 / 346 = 0.003
1 / 165 = 0.006
1 / 157 = 0.006
Graphs
On separate sheet of paper
Conclusion
On the graph for my results it shows that at the temperature 30 C the rate of reaction was 0.002, as the temperature rose to 40 C the rate of reaction increased by 0.001 making it 0.003. Between 40 C and 50 C there was a very large increase in the rate of reaction. It rose from 0.003 to 0.008 making a change of 0.005. This shows that as the temperature increase the rate of reaction (measured in reciprocal) increases. This is because the temperature provides more kinetic energy to the molecules involved, which means that more collisions can occur between the enzyme and the substrate making the rate of increase. At 50 C to 60 C the rate of reaction still increases but there is not a very large change, only by 0.002. This could be due to the denaturing of the enzyme which starts above 40 C. The bonds holding the structure of the enzyme together will be broken and the active site (where reaction take place) loses it’s shape and will no longer work. Hence the fact that reactions involving enzymes get slower at higher temperatures.
On the graph for the class results it also shows that between 40 C and 50 C there is a very large change in the rate of reaction. This means that collisions between the enzyme molecules and substrate increase. However at 50 C and 60 C the graph levels off which could mean that the enzyme trypsin has been denatured so the active site will no longer work.
In the results the highlighted areas also show that there was some denaturing of trypsin. As the temperature increases the time taken decreases so that could mean that the enzyme is no longer working properly.
So as the temperature increases the time taken for the filmstrip to clear also increase. But however at higher temperature (above 40 C) this is not always true as the enzyme trypsin could be denatured. So as the temperature increase the time taken for the filmstrip to clear could take longer.
Evaluation
In this experiment I used water baths instead of a bunsen burner and beaker of water because water baths keep the temperature constant. Where as the temperature would fluctuate if I used the bunsen burner and beaker of water. Using water baths also decrease the variables of the experiment making it more accurate. Another reason for using the water baths is the fact that it is a lot safer to use.
The enzyme trypsin will catalyse the hydrolysis of peptide, but due to the shape of it trypsin will only split bonds after a basic or straight chain amino acid e.g. gelatin. (Gelatin coated the photographic film)
In my opinion I think that the enzyme concentration had a big role in this experiment. The lower the enzyme concentration the more competition there will be for the active site. So the rate of reaction is slower. But a higher concentration there is less competition for the active site so the whole process is quicker.
There were many sources of error in this experiment as it was the first time I have done this sort of experiment. If I kept repeating the experiment then the error percentage would decrease. The enzymes being denatured also effected results of the experiment. This could be improved by using a different solution for every different temperature. When the film was dropped into the solution of trypsin, not looking /checking the film constantly could have increased the time in the experiment by a little. Checking the filmstrip for 30 C and 40 C every minute and the higher temperatures every 30 seconds could reduce this. Another error was that fact that I could not really tell when the filmstrip had gone clear. This is hard to improve but if I did experiment again I would know what to expect.
Additional work could be carried out to this experiment, like repeating the experiment but using a wider range of temperatures.