Two glucose molecules combine to form the disaccharide maltose. What byproduct forms, and what type of reaction occurred?

Core Concept

Monosaccharides join into disaccharides by condensation, also called dehydration synthesis. A hydroxyl group contributed by one glucose and a hydrogen contributed by the other combine and leave as water, while the remaining oxygen becomes part of a covalent glycosidic bond linking the two rings. Maltose therefore contains one alpha-1,4 glycosidic linkage, and each linkage formed releases exactly one water molecule. During digestion, maltase reverses the step by hydrolysis, adding water to split maltose back into two glucose units.