Monosaccharide and Disaccharide Overview
 

Glucose is the most common monosaccharide consumed by humans, and its metabolism has already been discussed. Two other monosaccharides, fructose and galactose, also occur in significant amounts in the diet (primarily in disaccharides) and make important contributions to energy metabolism. In addition, galactose is an important component of glycosylated proteins.  Figure 1 shows the metabolism of fructose and galactose as part of the essential pathways of energy metabolism.

Figure .1 Galactose and fructose metabolism as part of the essential pathways of energy metabolism.  UDP = uridine diphosphate; P = phosphate.