Question

Which of the following statements are correct?
(i) Chitin, a complex or heteropolysaccharide occuring in the exoskeleton consists of NAG.
(ii) Glucosamine and N-acetyl glucosamine (NAG) are modified sugars.
(iii) Cellulose shows blue colour when treated with Iodine.
(iv) Starch in plants and glycogen in animals are store houses of energy.
(v) Right end of polysaccharide is called the reducing end while the left end is called non-reducing end.

• A. All except (iii)
• B. All except (v)
• C. (i), (ii) and (iii)
• D. (iii), (iv) and (v)

Answer 1

The correct option is A All except (iii)

Iodine slips into the coil of the helical structure of starch causing a blue-black colour. While cellulose derived from D-glucose is a straight and linear polymer which cannot coil around iodine so does not show blue colour.