Biological Molecules: Structure and Methods of Analysis

I. Carbohydrates Carbohydrates are also called saccharides, which is derived from the Greek word sakcharon meaning sugar. The simplest carbohydrates are called monosaccharides, and the biologically important monosaccharides contain from 3 to 7 carbon atoms. The monosaccharides with 5 carbons (the pentoses) and with 6 carbons (the hexoses) may take on different configurations in an aqueous solution, randomly alternating between a linear and a ring form (Fig. 5.3). The pentoses are important in several biochemical pathways, but the two most common pentoses, ribose and deoxyribose, are critical structural components of nucleic acids as described later.