Two glucose molecules combine to form the disaccharide maltose. What occurs during this reaction?

Core Concept

Joining sugars into disaccharides and polysaccharides proceeds by dehydration synthesis, also called condensation. One glucose contributes a hydroxyl group and the other a hydrogen from its hydroxyl; these leave as a free water molecule while an oxygen bridge, the glycosidic linkage, covalently connects the rings. Hydrolysis is the reverse reaction and consumes water to cleave the bond. Ring opening in solution is reversible and is not what creates the linkage.