What is the basic structural difference between starch and cellulose?

Explanation

Starch is not a single compound but is a mixture of two components: (i) amylose ( a linear polymer of `alpha`-D-glucose and (ii) amylopectin ( a branched polymer of `alpha`-D-glucose). In both these components, D-glucose units are linked through `alpha`-glycosidic linkage between `C_(1)` of one glucose unit with `C_(4)` of the next glucose unit.
Cellulose is however a single compound. It is a linear polymer of `beta`-D-glucose. C-1 of one glucose unit is connected to C-4 of another through `beta-glycosidic linkage.