Mannose is a plant sugar. Note that these sugars differ in their geometric structure simply by the orientation of the -OH groups. To remember these sugars, I've got three mnemonics for you. This describes the orientation of the -OH groups on the first four carbons. This carbon is called the anomeric carbon, Figure 7 .
Humans metabolize monosaccharides in the a configuration.
The graphic, above, illustrates glucose in both configurations. The next group of carbohydrates that we're interested in are the disaccharides. The bonds that hold these sugars together are called glycoside bonds. The linkage between the glucose and fructose molecules in sucrose occurs through the 1 st and 2 nd carbons of glucose and fructose, respectively. Refer to the above graphics for clarification of the shapes of these bonds.