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Polysaccharides

A polysaccharide is a polymer formed from the condensation of several cyclic monosaccharides (pyrannoses or furannoses):

Cellulose

Cellulose is a (1→4) polymer of β-(D) -glucose

This is the main constituent of wood.

Cellulose is the most abundant organic material on earth (over $50\%$ of the biomass). The amount synthesized by plants is estimated at 50-100 billion tonnes per year! Cellulose is an important industrial raw material. It is used: - Either in the form of crude fiber in the manufacture of paper pulp. - Or, after conversion by the chemical industry in the manufacture of . artificial textile fibers: cellulose acetate, viscose, rayon, . carbon fibers, . cellulose acetate, cellophane, celluloid, collodion ..., . explosives: cellulose nitrate (nitrocellulose) . thermal insulators: panels, cellulose wadding ...

Amylose, amylopectin and glycogen

Amylose is a (1→4) polymer of α-(D)-glucose The amylopectin and glycogen have further (1→6) ramifications

Amylose (not branched) and amylopectin ( poorly branched) are vegetable reserve substances. Glycogen (highly branched) is an animal reserve substance that accumulates in the muscles and liver.

Image by Kirsten Ulve

The failure in endurance events (marathon, cross country skiing, cycling ..) comes mostly from the depletion of glycogen stores. This phenomenon is referred to as "hitting the wall" It seems that there are three ways to avoid this "wall": - Absorb glucose continuously during the test. - Practice a special diet before low intensity training (eat low carbohydrate before). - Practice still a special diet after depletion of glycogen (eat lots of carbohydrates).

Muscle glycogen greedy