What forms a disaccharide?

A disaccharide is formed when two monosaccharides are chemically linked together through a process that involves the formation of glycosidic bonds. This bond is a type of covalent bond that occurs between the hydroxyl group of one monosaccharide and the anomeric carbon of another, with the release of a molecule of water (a dehydration reaction). Common examples of disaccharides include sucrose (glucose + fructose) and lactose (glucose + galactose).

This understanding is fundamental in carbohydrate chemistry, as the size and properties of carbohydrates play a critical role in biological systems. Monosaccharides like glucose and fructose are the simplest forms of carbohydrates, and their combination into disaccharides is a key step in forming more complex sugars and carbohydrates, which serve various functions in living organisms.