What subunits make up poly-carbohydrates?

Carbohydrates are made up of glucose subunits . In complex carbohydrates long polymer chains of glucose subunits form the higher structure, they can be "nibbled" from either end by digestion enzymes. The breakdown into glucose is needed for metabolism.

Sugar units are called saccharides in chemistry. Starch and cellulose are polysaccharides made from glucose. The difference in starch and cellulose is the manner in which the glucose units are bonded. Humans do not have the enzymes to digest cellulose.

Simple sugars consits of small clusters of glucose, fructose and glactose subunits, amongst others that are all structually similar. Lactose found in milk is a carbohydrate sugar made from a glucose and galactose subunit.