Question

Study the experimental set up shown below.
Which of the following statements is correct regarding the observations made, after the two visking tubes P and Q were placed in dilute iodine solution for 10 minutes ?
[Key : Visking tube allows the molecules of iodine to pass through it.]

• A. Solution in visking tube P turns blue - black
• B. Solution in visking tube Q turns blue - black
• C. Solution in both the visking tubes P and Q turns blue - black
• D. Solution in neither of the visking tubes turns blue - black

Answer 1

Answer: (A)

Solution in visking tube P turns blue - black

If the salivary amylase is boiled, then it will denature the enzyme and will no longer break down the starch to simpler sugars.
Boiling an enzyme denatures the proteins within, and the iodine test - which turns a starch blue with a continued presence of the starch- tells whether or not the starch has been broken down to saccharides.