How do monosaccharides combine to form polysaccharides?

Monosaccharides combine to form polysaccharides through a process called condensation (dehydration) reaction.

Here’s how it happens step by step:

1. Monosaccharides as building blocks:
   • Monosaccharides are simple sugars like glucose, fructose, and galactose.
   • They contain several hydroxyl groups (-OH) and one carbonyl group (C=O).
2. Formation of a glycosidic bond:
   • When two monosaccharides join, a hydroxyl group (-OH) from one sugar reacts with a hydrogen atom (H) from another sugar’s hydroxyl group.
   • This reaction releases a molecule of water (H₂O) — hence the name condensation or dehydration reaction.
   • The two monosaccharides become linked by a glycosidic bond (C–O–C).
   Example:
   Glucose + Glucose → Maltose + H₂O
3. Formation of polysaccharides:
   • The same process continues many times, with additional monosaccharides joining the chain.
   • This forms long chains called polysaccharides, such as starch, glycogen, or cellulose.
4. Bond type:
   • The glycosidic bonds can be α (alpha) or β (beta) depending on the orientation of the hydroxyl group on the carbon atom involved in bonding.
   • This determines the structure and function of the polysaccharide (e.g., α-linkages in starch, β-linkages in cellulose).

In short:
Monosaccharides combine to form polysaccharides by condensation reactions, where water is removed and glycosidic bonds are formed between sugar units. Repeating this process builds long carbohydrate chains used for energy storage (like starch and glycogen) or structural support (like cellulose).