The process of linking monosaccharides to become polysaccharides is while breaking down polysaccharides, like glycogen, occurs during a process

The process of linking monosaccharides to form polysaccharides is called anabolism while the breaking down of polysacchirides such as glycogen occurs during a process called catabolism.

Anabolism is the synthesis  of complex molecules from smaller molecules in a series of reactions usually requiring energy. The anabolic process uses monomers to build polymers.

Catabolism is the breakdown of complex molecules to simpler molecules often with release of energy. The catabolic process  breaks down polymers to monomers.

Glycogen, starch and cellulose are polysaccharides. During catabolism they are broken down into monomers such as glucose,  ribose and fructose.

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