Right end of a polysaccharide chain is called reducing end while left end is called non-reducing end. ii. Starch can hold iodine molecules in its helical secondary structure but cellulose being non-helical, cannot hold iodine. ... Starch and glycogen are the reserve food materials of plants and animals, respectively.

Does glycogen react with iodine?

When treated with iodine, glycogen gives a reddish brown color. Glycogen can be broken down into its D-glucose subunits by acid hydrolysis or by the same enzymes that catalyze the breakdown of starch.

Does glucose give a positive iodine test?

Mainly glucose is responsible for the positive iodine test.