However, β-glucans can be more diverse than molecules like starch. For instance, a β-glucan molecule can be composed of repeating D-glucose units linked with β-glycosidic bonds at one position like starch, but have branching glucose side-chains attached to other positions on the main D-glucose chain. These smaller side-chains can branch off the β-glucan “backbone" (in the case of starch, the backbone would be D-glucose chains linked at the (1,4) position) at other positions like that of the 3 and 6 position. In addition, these side-chains can be attached to other types of molecules, like proteins.