polysaccharide
Meaning of polysaccharide: A polysaccharide is a large carbohydrate built from many linked sugar units, a category that includes dietary starch, stored glycogen, and structural fibers.
Definition of polysaccharide
A polysaccharide is a large carbohydrate molecule made up of many smaller sugar units, called monosaccharides, linked together in a chain through chemical bonds. Because these chains can vary greatly in length and branching pattern, polysaccharides differ widely in their physical properties and biological roles.
Starch, found in foods such as grains and potatoes, and glycogen, the storage form of glucose kept in the liver and muscles, are polysaccharides used by plants and the body, respectively, to store energy for later use. Cellulose, a structural polysaccharide found in plant cell walls, cannot be broken down by human digestive enzymes and instead passes through the digestive tract as dietary fiber.
Chitin, another structural polysaccharide, forms the cell walls of fungi and the exoskeletons of insects, illustrating how the same broad chemical category includes molecules used for energy storage in some organisms and structural support in others.
Also known as
Used in a sentence
Laboratory analysis identified a polysaccharide component within the bacterial cell wall sample.
Good to know
Polysaccharides can serve very different biological roles depending on their structure, so the same broad chemical classification includes energy storage molecules such as glycogen and indigestible structural fiber such as cellulose.
Word origin
Where “polysaccharide” comes from
Formed from Greek polys, meaning many, and saccharide, from sakcharon, meaning sugar.