Starch has 2 components namely amylose and amylopectin. Amylose is a long unbranched chain made of α-D-(+)-glucose units held by C1 – C4 glycosidic linkage.
Amylopectin is a branched chain polymer of α-D-glucose units in which chain is formed by C1 – C4 glycosidic linkage whereas branching occurs by C1 – C6 glycosidic linkage. Cellulose is a straight chain polysaccharide composed of only β-D-glucose units joined by C1 – C4 glycosidic linkage.