Carbohydrates
A carbohydrate is a molecule that is carbon-based and contains many hydroxyl groups. The most simple of the carbohyrdates are monosaccharides which are lone carbohyrdates. Disaccharides are carbohydrates made up of two monosaccharides which are joined by an O-glycosidic bond. Carbohydrates can increase in size more by further addition of monosaccharides, complex carbohydrates containing more than one molecule are called oligosachharides.
Jeremy M. Berg, John l. Tymoczko, Lubert Stryer with Gregory J gatto, Jr, (2012), Biochemistry, International 7th edition, W.H Freeman and company