Starch is a type of which carbohydrate category?

• A. Monosaccharide
• B. Disaccharide
• C. Oligosaccharide
• D. Polysaccharide

Answer: (D)

Carbohydrates are categorized by how many sugar units they contain. A monosaccharide is a single sugar unit, a disaccharide is two linked sugar units, an oligosaccharide has a few to about ten units, and a polysaccharide consists of many sugar units linked into a long chain. Starch is made up of long chains of glucose units, so it forms a polymer and functions as a storage carbohydrate in plants. Its glucose units are linked mainly by alpha-glycosidic bonds, in two forms: linear amylose and branched amylopectin. Because it is a long, multi-unit carbohydrate, starch is classified as a polysaccharide.