Polysaccharides long chains of monosaccharide (simple sugar) units linked together by glycosidic bonds . They are complex carbohydrates that serve structural , storage , and functional roles in both plants and animals.
Structure: Made up of repeating monosaccharides (e.g., glucose , galactose, mannose). Can be:Linear (e.g., cellulose)Branched (e.g., glycogen , amylopectin) Classified as:Homopolysaccharides : All repeating units are the same sugar (e.g., starch made of glucose)Heteropolysaccharides : Composed of different sugars (e.g., hyaluronic acid) Functions: Function Description Examples Energy storage Reserve fuel for later use Starch (plants), Glycogen (animals) Structural support Maintain cell shape and structure Cellulose (plants), Chitin (fungi, arthropods) Biological signaling and protection Lubrication , immune modulationMucopolysaccharides (e.g., hyaluronic acid, heparin)
Examples of Polysaccharides: Polysaccharide Type Role Found In Starch Homopolysaccharide (glucose) Energy storage in plants Potatoes, grains Glycogen Homopolysaccharide (glucose) Energy storage in animals Liver , muscles Cellulose Homopolysaccharide (glucose) Structural support in plant cell walls Plants Chitin Homopolysaccharide (N-acetylglucosamine) Exoskeleton structure Insects, fungi Hyaluronic acid Heteropolysaccharide Lubrication, tissue hydration Connective tissues, joints
Properties: Insoluble or poorly soluble in water (especially structural polysaccharides like cellulose).Can be digestible (starch, glycogen) or indigestible to humans (cellulose). Vary greatly in size , branching , and chemical modifications , contributing to a wide range of functions. Polysaccharides vs. Other Carbohydrates: Type Structure Example Digestibility Monosaccharide Single sugar unit Glucose Easily absorbed Disaccharide Two sugar units Sucrose Digestible Polysaccharide Many sugar units Starch, Cellulose Varies by type
Biological and Industrial Significance : Nutrition : Major component of diet (e.g., dietary fiber from cellulose).Pharmaceuticals : Used in drug delivery systems (e.g., dextran).Biotechnology Medical applications : Hyaluronic acid in eye surgery and joint treatments.Summary Table: Feature Description Basic Unit Monosaccharides (e.g., glucose) Bond Type Glycosidic bonds Function Storage, structure, signaling Types Homo- and heteropolysaccharides Common Examples Starch, glycogen, cellulose, chitin, hyaluronic acid
