(Saccharides or sugars) Monosaccharides (simple sugars) Oligosaccharides ( to sugar units) Di - saccharides Tri - saccharides Tetra - saccharides Penta - saccharides Hetero polysaccharides Homo polysaccharides Polysaccharides ( more than10 sugar units) Functional Examples group Aldoses Trioses Glyceraldehyde e Maltose Raffinose Starch Stachyose Verbascose Lactose Glycogen Sucrose Cellulose Chondroitin sulphate Chitin Inulin Tetroses Erythrose Pentoses Ribose Number of carbon atoms Peptidoglycan Hyaluronic acid Keratan sulphate Agar agar Glucose Ketos Fructose Hexose Glucose Classification of Carbohydrates - - . . PM . .
Polysaccharides These are made of hundreds of monosaccharide units . Polysaccharides also called " Glycans ". Long chain of branched or unbranched monosaccharides are held together by glycosidic bonds. Polysaccharide is an example of giant molecule, a macromolecule and consists of only one type of monomer.
Polysaccharides are insoluble in water and are sweetless. Cellulose is an example built from repeated units of glucose monomer (Figure . ). Figure .
: Branched and linear polysaccharides Depending on the function, polysaccha- rides are of two types - storage polysaccha- ride and structural polysaccharide. . . Starch Starch is a storage polysaccharide made up of repeated units of amylose and amylopectin .
Starch grains are made up of successive layers of amylose and amylopectin, which can be seen as growth rings. Amylose is a linear, unbranched polymer which makes up % of starch. Amylopectin is a polymer with some , linkages that gives it a branched structure. .
. Test for Starch We test the presence of starch by adding a solution of iodine in potassium iodide. Iodine molecules fit nearly into the starch helix, producing a blue-black colour . Amylose Amylopectin Starch Glycogen Cellulose (fibre) Glucose has a chemical formula of C H O .
It is a six carbon molecule and hence is called as hexose. All monosaccharides contain one or two functional groups. Some are aldehydes, Eg: glucose and are referred as aldoses ; other are ketones, Eg: fructose and are referred as ketoses . Glucose is one of the most well-known molecules due to its nature as an essential nutrient for human