Diagram
Apparatus
Test tubes x15
Pipettes x3
Starch
Amylase
Iodine
Conical flasks x10
Water baths x5
Clamp stands x10
Clamps x10
Test tube rack
Stopwatch
Amylase
Amylase is an enzyme in which it breaks down starch to maltose and to glucose. As with any other enzyme, amylase is a catalyst. This means that it is unchanged by the reaction, but makes the reaction easier by reducing the energy required for it to happen. A catalyst speeds up a reaction but does not get used itself. Salivary amylase is known as ptyalin. Ptyalin begins digestion in the mouth, and the process is completed in the small intestine by the pancreatic amylase, known as amylopsin.
Body temperature is optimal for the best reaction of amylase (as with other enzymes) - if the temperature is too high, then the amylase will denature, and if too low, the reaction slows to a stop.
The temperatures that will be used in this investigation are 0°C, 20°C, 40°C, 60°C and 80°C.
Because of these factors, I expect the optimum temperature to be 40°C. This prediction is based upon the fact that it is closest to 37 °C (body temperature).
Method
Firstly, 5ml of starch will be added to each test tube. Two drops of iodine will then be mixed in with the starch to create a blue coloured solution.
The importance of the iodine is to show the amylase breaking down the starch visually by giving it colour. Without it it would be impossible to tell when the amylase had finished breaking down the starch, i.e. when the solution changes from a blue colour and becomes colourless.
After this 5ml of amylase will be added to each test tube and then timed from the moment the amylase comes into contact with the starch and iodine solution until the whole solution becomes colourless.
This process will be repeated three times for each of the five temperatures.
Safety
A great deal of care must be taken due to the possibility of scalding due to hot water, starch or amylase; especially the 80°C liquids. Goggles will be worn at all times to help to minimize the possibility of injury.
Conclusion
From the results we can see that the 40°C provided us with the fastest time in which to break down the amylase. This supports my prediction. It has also shown that when the amylase is working at 0°C it is a poor catalyst and takes quite a while to break down the starch. There is no obvious numerical link that could be made from my results.
Evaluation
My experiment did go as planned, and there were no real problems as far as conducting the experiment goes. From looking at the results charts, there is one possible anomalous result, where the second 20°C investigation took much longer than the first and third ones. This is almost certainly due to human error, possibly not mixing the starch in with the iodine well enough.
The experiment could be improved by making the individual tests faster so as to keep the temperatures better.
