Question on Enzymes

Describe how you would investigate the effect of temperature changes on the activity of the enzyme amylase. [10m]

1. Use a dropper to place drops of iodine solution on a white tile.
2. Label five test tubes 10, 30, 50, 70, 90 to indicate the temperatures at which they would be incubated at and add 10 cm3 of starch suspension into each of these tubes.
3. Use the five beakers provided to set up water baths maintained at temperatures of 100C, 300C, 500C, , 700C and 900C respectively.
4. Place each of these tubes in their corresponding water baths and leave them for 10 minutes.
5. After 10 minutes, add 1 cm3 of amylase solution into each test tube and shake the test tube gently. Immediately after adding the amylase solution, start the stopwatch and return the tube to the water bath.
6. Use clean plastic droppers to remove one drop from each of the starch-amylase mixtures and add them to the iodine droplets on the white tile to test for the presence of starch.
7. Repeat step 6 at regular intervals of 2 minutes for the next 15 minutes, and ensure that the temperature of the water baths does not fluctuate too much.
8. For each of the test tubes, record the time taken for starch to be digested completely (when iodine solution remains yellow).
9. Plot a graph of the time taken for the complete digestion of starch against temperature.
10.The shorter the time taken to digest the starch, the faster the rate of reaction indicating faster enzyme activity.