Method:
- Add a droplet of iodine consecutively in each dimple of the dimple tray with a pipette.
- Measure 2 ml of amylase and 6ml of starch solution each in a measuring cylinder.
- Add the solution of starch into a test tube
- Modify the temperature of its surroundings. If it’s cooler than room temperature, then the test tube should be put in a large beaker of ice and water should be added fitting the appropriate temperature (such that of 5 degrees Celsius). If the temperature is warmer than room temperature, then the test tube should be put into a hot bath fitted onto the test tube rack so the solution doesn’t fall out.
- Add the bacterial amylase into the solution and start timing immediately
- After every 15 seconds a single droplet of the solution should be transferred onto the dimple tray with a pipette
- This process should be done consecutively in rows (for every 15 seconds) of the dimple tray until the iodine indicator turns from blue/black to a chocolate brown colour indicating that there is a lack of starch present.
- Use three trials for each temperature value.
Data collection and processing (DCP):
Average was found finding the total of each three trials and then dividing it by three.
Trends and pattern from Graph:
The general trend seen from this graph is that when temperature is increased, the rate of bacterial amylase reaction is much faster and works more effective. The substrate and enzyme is more likely to attach to each other as the temperature increases. The graph doesn’t show the denaturising of the bacterial amylase. The enzyme was measured also at 80 degrees Celsius because the test had not shown any denaturising when it had been 75 degrees Celsius. The bacterial amylase shows that it is very consistent in high temperature and it shows that it can survive in an environment where the climate is very hot and dry.
Source:
Conclusion:
At low temperature the rate of reaction is slower because there isn’t enough energy for the substrate and enzyme to meet, collide and then the reaction to happen. Kinetic energy between the enzyme and the substrate is very low and therefore fewer collisions are present. There’s also a lack of energy to make the reaction happen for activation to occur. As the temperature increased it provided more energy for collisions for the reactions to occur at a higher rate until optimum is reached. Beyond optimum temperature, the rate of reaction stops and the enzyme denatures because the bonds in the enzyme are broken and the structure loses its shape. In this experiment, bacterial amylase was used to interpret the rate of enzyme reaction. The graph had clearly indicated this process. The Solution showed that there’s a lack of starch and as the temperature was increased the amount of time taken for this reaction to happen was shorter and shorter.
My prediction (which was correct) was that the enzyme reaction will increase as temperature increases; however, the bacterial enzyme had not shown any sign of denaturation during the whole experiment which showed that the enzyme can work effectively under extremely high temperature conditions and denatures at much higher temperature than normal amylase used for digestion. My second prediction was also correct! I also predict that when the temperature is high (approximately 40 degrees Celsius), the rate of enzyme reaction is twice as faster than it is when the temperature is low (approximately 5 degrees Celsius) due to its activation energy.
The uncertainties in this experiment depended on human error that was seen with the eye because the reaction had taken place once the color of the iodine solution had changed. The error bars in the graph indicate the minimum and maximum values of the experimental values achieved. The larger the error bar in length, the more likely it was that the experiment
Evaluation of Procedure
The procedure was effective because the color change could be detected in the dimple tray easily if there was a lack of starch present. The indicator showed Blue if the solution had starch present and showed chocolaty brown if the solution had a lack of starch.
Weaknesses –
It was hard to use the pipette every 15 seconds because of strenuous labor that made excess droplets be put on the dimple tray which could have had an impact on the results obtained.
The exact amount of time could not be measured at which the iodine solution changes its colour and therefore there were some errors in reactions that had happened in a short amount of time. The results obtained could be tested for 15 seconds per result and this was slightly ineffective because it had not shown the exact time at which the enzyme had been processing with the active site.
A more effective procedure would be if the iodine was directly put into the test tube of starch and amylase solution right after the amylase is put into the test tube. The amount of time taken for the reaction to occur can be measured exactly from reaction when the indicator changes color at the given temperature.
Improving the investigation
To measure the exact amount of time for the reaction to happen in order get more accurate results, a different method would have been more useful like the one indicated above. However, a color indication comparison paper (just like pH scales) for iodine solution would have been more effective in the process of comparing the color after every 15 seconds for the experiment.
If I did the experiment again, I would also have used more than 3 trials even though the error bars from the graphical results obtained were close together from the maximum and minimum values.