Specifically, starch is composed of two types of glucose polymers:

* Amylose: A linear chain of glucose monomers linked by α-1,4-glycosidic bonds.

* Amylopectin: A branched chain of glucose monomers linked by α-1,4-glycosidic bonds, with occasional α-1,6-glycosidic bonds creating the branches.

So, while the monomer is the same (glucose) for both, the way they are linked together creates the two different forms of starch.