Name two components of starch. How do they differ from each other structurally?

Explanation

Starch consists of two components (i) amylose and (ii) amylopection. Although , both these components are made of `alpha` - D-glucose units yet they differ in the manner in which the different `alpha`-D-glucose units are linked to one another.
Amylose is a linear condersation polymer of `alpha`-D-glucose in which `C_1` of one glucose unit attached to `C_4` of the other through `alpha`-glycosidic linkage as shown in fig.
(ii) Amylopectin , on the other hand is a highly branched polymer. It consists of a large number (several hundreds ) of short chains each containing `20-25` glucose units which are joined together through `alpha` -glycosidic linkages involving `C_2` of one glucose unit with `C_4` of the other. The `C_1` of terminal glucose unit in each chain is further linked to `C_6` of some other glucose unit in the next chain through `C_1-C_6 alpha` -glycosidic linkage.This gives amylopectin a highly branched structure as shown in fig.