The Student Room Group

Can someone help me with this Biology question please?

A student took a sample of 100% pure starch and added the enzyme amylase to it. After 1 hour, they tested the solution using the Benedict’s, iodine, emulsion and biuret tests. Which tests would be positive and why?
Emulsion and Biurets test for lipids and proteins respectively, obviously both would be negative. Amylase breaks starch down into glucose, thus Benedicts (glucose test) would test positive. Iodine (starch test) may also be positive as some starch may remain.
Original post by SorcerousSheep
Emulsion and Biurets test for lipids and proteins respectively, obviously both would be negative. Amylase breaks starch down into glucose, thus Benedicts (glucose test) would test positive. Iodine (starch test) may also be positive as some starch may remain.

Wouldn't amylase, as a protein cause the biuret test to be positive.

Quick Reply