Question

From the image below, which of the following statement(s) is/are correct?

• A. The red colour in test tube A is due to the presence of starch
• B. The blue-black colour in the test tube B is due to the presence of starch
• C. The enzyme action is seen in test tube A
• D. The enzyme action is seen in test tube B

Answer 1

Answer: (B), (D)

The correct options are
B

The blue-black colour in the test tube B is due to the presence of starch

D

The enzyme action is seen in test tube B

In test tube A, saliva (salivary amylase) is added to starch solution, the solution will turn red or yellow because salivary amylase acts upon starch and digests it. In test tube B, the saliva or salivary amylase is not added to the starch solution. The solution will turn blue-black when iodine is added to it because in absence of salivary amylase, digestion of starch has not taken place.