A carbohydrate formed from many monosaccharides joined together in long linear or branched chains. Polysaccharides have two important functions: (1) as storage forms of energy; for example glycogen in animals and starch in plants, and (2) as structural elements; for example mucopolysaccharides in animals and cellulose in plants.

Unit 2,

Reference: Oxford Concise Colour Medical Dictionary (7th Edition, Kindle Edition) Oxford University Press 2020 ISBN-13: 978-0198836629, p2153