1.4—Glycosidic bonds, condensation and hydrolysis

A condensation reaction joins two monosaccharides while releasing water. The new covalent link is a glycosidic bond; hydrolysis adds water to break that bond and release smaller sugars.

The bond name records the carbon positions involved. For example, maltose has a 1,4 glycosidic bond between two glucose molecules, while sucrose joins glucose and fructose through a 1,2 link.

The same monomers can make molecules with different properties because bond position and orientation change branching, shape and enzyme access. Hydrolysis is therefore a controlled way to release absorbable sugars.

Digestive enzymes hydrolyse a disaccharide into monosaccharides before absorption. In a plant, repeated condensation builds a polysaccharide store and releases water at each bond formed.

Condensation forms the bond; hydrolysis breaks it. Do not say that a glycosidic bond is ‘a sugar molecule’ or assume all glucose polymers have the same structure.