Question

Two test tubes A and B are taken, each containing one ml of starch solution. Add 1 ml of saliva to test tube 'A' only and leave both the test tubes undisturbed for a few minutes. Now add a few drops of dilute iodine solution to both the test tubes.

1. Which one of the two test tubes shows change in colour? Write the changed colour observed in this test tube.
2. What can we conclude from this activity?

Answer 1

1. Test tube A will show a change in colour from blue-black to light yellow-brown.
2. This shows the process of enzymatic digestion of starch due to amylase present in saliva.