What is a disaccharide?

A disaccharide is correctly identified as a double sugar molecule made up of two monosaccharides. Disaccharides form when two monosaccharide molecules undergo a dehydration synthesis reaction, resulting in a glycosidic bond that connects them. Common examples of disaccharides include sucrose (made from glucose and fructose), lactose (made from glucose and galactose), and maltose (made from two glucose units).

Understanding what constitutes a disaccharide is important because it highlights the fundamental building blocks of carbohydrates and helps distinguish these from simpler or more complex carbohydrates. Monosaccharides represent the simplest form and are the single sugar units, while complex carbohydrates consist of multiple sugar units linked together, which differ from the simpler disaccharide structure.