Question

Main chain of glycogen and starch is helically coiled with each turn of helix having

• A. $10-14$ glucose residues
• B. $8-10$ glucose residues
• C. $6$ glucose residues
• D. $4$ glucose residues

Answer 1

Answer: (C)

$6$ glucose residues

Animal cells store food in the form of glycogen. It is formed by linkage of glucose molecule in a linear chain with 1,4 alpha linkage and alpha 1,6 side linkage.

Starch is formed by a-1,4 linkages between two glucose unit which is broken down during its digestion. It exist in two forms known as amylose and amylopectin. Amylose is a linear poly-D-glucose in which the monosaccharides are connected by alpha 1, 4 linkages. Amylopectin is has alpha 1, 4-glycosidic linkages with side chain branching of alpha 1,6 linkage.

Both the structure has side branching at sixth residue so each turn has six glucose residue.

So, the correct answer is option C.