Final answer:
Sucrose is a disaccharide consisting of glucose and fructose joined by a glycosidic linkage. Cellulose and starch are polysaccharides, not disaccharides. The bond in the disaccharide lactose is a glycosidic linkage between glucose and galactose.
Step-by-step explanation:
Sucrose is an example of a disaccharide(d). A disaccharide is a type of carbohydrate made up by joining together two monosaccharides. In the case of sucrose, it is composed of a molecule of glucose and a molecule of fructose bonded together by a glycosidic linkage. Other examples of disaccharides include lactose, which is made from glucose and galactose, and maltose, which consists of two glucose molecules. Disaccharides like sucrose are commonly referred to as simple sugars and are a major source of energy for living cells.
Cellulose and starch, by contrast, are not disaccharides but polysaccharides. They are long chains of glucose units bonded together and serve as structural and energy-storage molecules, respectively. The bond that joins the molecules in the disaccharide lactose is also a glycosidic linkage, with glucose being joined with galactose to form lactose.