Final answer:
Disaccharides are carbohydrates composed of two monosaccharides joined by a glycosidic bond. The three common disaccharides are sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (two glucose molecules). They need to be hydrolyzed into monosaccharides before the body can utilize them.
Step-by-step explanation:
What Are Disaccharides?
Disaccharides are a type of carbohydrate made up of two monosaccharide molecules linked together by a glycosidic bond. This bond is formed through a dehydration synthesis reaction. The three common types of disaccharides each contain glucose as one of their components. These include sucrose, or table sugar; lactose, or milk sugar; and maltose, or malt sugar.
Sucrose is a disaccharide composed of glucose and fructose and is the most common type consumed. Lactose consists of glucose and galactose and is found naturally in milk. Lastly, maltose is formed from two glucose molecules. While these sugars are ingested through our diet, they must be broken into their monosaccharide forms via hydrolysis to be utilized by the body.
Maltose and sucrose have alpha-bonds in their structures, whereas lactose contains a beta-bond, which necessitates a specific enzyme, lactase, for digestion; the absence of lactase can lead to lactose intolerance.