Yes, a monosaccharide is considered a monomer. Monosaccharides are the simplest form of carbohydrates and are the basic building blocks for more complex carbohydrates, such as disaccharides and polysaccharides.
A monomer is a small molecule that can join together with other similar molecules to form a larger structure, known as a polymer. In the case of carbohydrates, monosaccharides like glucose, fructose, and galactose can combine through glycosidic bonds to create more complex sugars. For instance, two monosaccharides can link to form a disaccharide, like sucrose or lactose. Similarly, numerous monosaccharides can join to form polysaccharides, such as starch or glycogen.
In summary, since monosaccharides serve as the fundamental units that can link together to create larger carbohydrate structures, they indeed qualify as monomers.