To make sure that my results were valid I
- Checked the temperature of the water was correct.
- Made sure the film strips were the same size and shape
Prediction
I believe that at 20oC the protease enzymes will have little or no effect upon the film strips. This is because of the Collision theory – the warmer the enzymes, the more energy they will contain, therefore resulting in them moving around more and more rapidly, this will result in each protease enzyme colliding with the film strips more and more frequently. As each enzyme collides into the film strip, it will break down the protein it contains. So, at 20oC the enzymes will contain little energy so will have little effect upon the film strip. However, as the temperature increases to 30oC, I believe that the reaction between the film strip and the protease enzymes will show a significant improvement, again, this being because of the Collision Theory. The speed of the reaction will continue to increase until approximately 50oC, until now the Collision Theory has been working to great effect. When the temperature increases to above 50oC, the reaction speed will take a dramatic downhill affect, this being the result of denaturing. Although the collision theory is still effectively being put into practice, the protease enzymes will begin to become this is because the extreme heat is beginning to negatively affect the size and shape of the enzymes, leaving them unable to effectively break down the protein in the film strip. I predict that this process will begin to take a noticeable effect at around 60oC, from here on the reaction will be slower and slower. At 80oC I believe that the reaction will be extremely slow or completely stop, due to the fact of the enzymes being completely denatured.
Results
Analysis
My results clearly show that temperature does have a direct on enzyme activity. Most of my prediction was accurate and correct. At 20oC the enzymes failed to impose any significant effect onto the film strip, after 300 seconds I decided to stop timing, I decided to make this the maximum time for each reaction. This was mainly due to the lack of time given for the experiment. The reason for the protease failure to react was as I predicted – The Collision Theory – because the enzymes were given little heat to feed off, little energy was produced, resulting in each enzyme seldom colliding into the film strip. This therefore resulted in the protein within the film strip being attacked and broken down less and less effectively.
As the temperature increases to 30oC, a dramatic change is visible. As the temperature has increased, the energy within each enzyme has also increased, resulting in each enzyme colliding with the film strip more often and therefore is beginning to break down the protein more effectively.
At 40oC, a slight improvement in speed of reaction has been made, but however, not as drastic as the previous reaction time. It is again apparent that the Collision Theory is still working effectively with more heat and energy been given to each enzyme. The protease enzyme is now almost working at its peak and is continuing to work extremely hard to break down the protein within the film strip. As you can see from the graph, 117 seconds is just above the average time that the protein is now broken down in.
50oC is obviously the peak time for enzymes breaking down proteins. It is almost 33% quicker than the previous recorded time, showing that the collision theory is working to perfection. The temperature is just right for the enzymes to be given maximum energy, without being denatured, to effectively collide with the film strips and break down the contained protein with maximum effect.
As the temperature increases, the reaction becomes more efficient, up to an optimum at 50oC. After this, any further temperature rise leads to a decrease in efficiency because of the beginning, and the eventual complete denaturing (the changing of the shape of enzymes, resulting in the enzymes having great difficulty, and eventually finding it impossible, to break down and digest protein foods) of the enzymes. This is shown at just 60oc, where the process of denaturing is beginning to take action, where the reaction time is slowed by almost 30 seconds. At 60oC the enzymes will begin to be denatured, with them starting to slightly change shape and finding greater difficulty in breaking down the proteins quickly and effectively.
A 10 Degree increase sees a 9 second increase in time taken to break down the film strip protein completely; however, although the enzymes have been denatured further, they are still more effective than they were at 20oC, 30oC and 40oC. This is because, although more and more enzymes are being denatured, the collision theory is working very effectively. So, although the enzymes may be denatured by 25%, the collision theory could be working 50% harder and more effectively than the temperatures of 20oC, 30oC and 40oC, resulting in the protein still been broken down quite effectively.
For 80oC, I predicted that the enzymes would be completely denatured, resulting in the protein failing to be broken down. It appears that I am wrong as the protein on the film strip appeared to be broken down after just 89 seconds, the second fastest time recorded. This could be because of the amount of collisions cancelling out the fact that the enzymes have been almost completely denatured, therefore resulting in a speedy reaction time. However, I believe that this reaction time is not a reaction at all and that the protein on the film strip has simply melted in the intense heat, therefore appearing to have been broken down completely. I think this is the better theory out of the two because of the fact that the two temperatures previous to this, both increased, due to the denaturing of the enzymes.
To conclude, my predictions were almost completely accurate, I think with maybe a different type of film strip (possibly harder wearing) would give a more accurate and realistic result.
Evaluation
I believe that the experiment was successful but some of the results were unreliable. The time taken for the enzymes to break down the protein at 80oC was far too fast. I believe that this should have taken 300+ seconds as the enzymes had been denatured by this time, however, the rest of the results followed a pattern which seemed to be accurate and correct.
I found that the experiments was designed well but did have a number of problems which should have been changed and/or improved
- It is extremely difficult to time three separate film strips with only one stop watch. One stopwatch should be provided for each film strip.
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However, even if one stopwatch was provided for each film strip, it is impossible to watch all three film strips at a time, their progress may be very close together but still different, so each film strip must be viewed 100% of the time. This was not possible. This could be improved by only one film strip being allowed to be tested at a time; however, this could prove to be difficult given the amount of time allowed for the experiment.
- When the proteins on the film strips began to dissolve, the test tube was filled with a cloudy-like substance (the dissolved protein) this made it very difficult to view further advances in the dissolving of the film strip. To further this problem, you cannot lift the film strip out of the substance as the protease enzymes will not be allowed to work, resulting in the test not being fair. Also you cannot stir the enzymes as; again, this could result in the test not being fair.
- Although the film strips were the entire same make, they were not all exactly the same size and shape, again resulting in the experiment being unfair. While one film strips protein could take 100 seconds to dissolve, a larger film strip s protein could take maybe 110 seconds to dissolve, however, from this you cannot predict whether the size had the effect on the time taken or it was the enzymes, resulting in an unfair test.
One of the biggest problems I encountered was the fact I struggled to keep each temperature accurate. It was extremely difficult to reach my desired temperature to begin with, when the temperature was reached , it was almost impossible to keep the temperature the same, as it often began to increase or decrease to room temperature, again resulting in an unfair test. One thing that could be done to solve this problem is to use an electric water bath, by using this I could select the appropriate temperature and have no problems with the temperature changing as an in-built thermometer would ensure the temperature would stay the same
