Question

Which of the following statement(s) is/are correct with respect to starch?

• A. It is a reducing carbohydrate
• B. It is a polymer of α-D-glucose
• C. It consists of branched chains
• D. It consists of amylose and amylopectin

Answer 1

Answer: (B), (C), (D)

It consists of amylose and amylopectin

Starch is a non-reducing saccharide as it does not reduce Fehling’s solution or Tollen’s reagent. This indicates that all hemiacetal hydroxyl groups of glucose units are not free but are linked by glycosidic bonds.

Starch is polymer of $\alpha$-D-glucose only.
Starch consist of two components amylose and amylopectin.
Amylose is a polysaccharide made of several $\alpha$-D-glucose units. They are linked by $C_1-C_4$ glycosidic bonds.
Amylopectin is a branched polymer of several $\alpha$-D-glucose molecules. Amylopectin constitutes 80% of starch. Amylopectin molecules are linked by $C_1-C_4$ glycosidic bonds and $C_1-C_6$ glycosidic bonds.