Principles of Biochemistry Volume 1 - A. Lehninger 1985

Biomolecules
Carbohydrates: Structure and Biological Functions
Polysaccharides contain a large number of monosaccharide residues

In nature, the majority of CARBOHYDRATES occur as high-molecular-weight Polysaccharides. The Biological Significance of certain polysaccharides lies in their role as storage reservoirs for Monosaccharides, whereas others serve as Structural components of Cell walls and Connective Tissue. Upon complete Hydrolysis mediated by acids or specific Enzymes, polysaccharides are cleaved to yield monosaccharides or their derivatives.

Polysaccharides, also referred to as glycans, vary widely in The Nature of their constituent monosaccharide residues, chain lengths, and degrees of branching. They can be divided into two main types: Homopolysaccharides, which consist of residues of a single type of monosaccharide, and Heteropolysaccharides, which contain residues of two or more different monosaccharides. An example of a homopolysaccharide is the storage carbohydrate starch, which is composed exclusively of D-glucose residues. An example of a heteropolysaccharide is hyaluronic acid found in connective tissue, which consists of alternating residues of two different monosaccharides. Unlike Proteins, polysaccharides cannot be characterized by a strictly defined molecular weight: as a rule, they exist as mixtures of high-molecular-weight compounds. Depending on the metabolic demands of The Cell, monosaccharide residues can be enzymatically added to or cleaved from the polysaccharide chains.



Last update: 06/08/2026

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