The six-membered cyclic form of a monosaccharide. A carbohydrate that cannot be hydrolyzed into simpler carbohydrates. A carbohydrate consisting of a four carbon chain. A carbohydrate consisting of a three carbon chain. A saccharide with a five carbon chain that includes a ketone is termed a ketopentose.
All natural carbohydrates are in the D configuration.
In the pyranose or furanose ring, locate the ring carbon attached to the primary alcohol unit. This carbon will also be attached to the ring oxygen. The carbon on the other side of the ring oxygen is the anomeric carbon. An a or b configuration refers to the stereochemistry at the anomeric carbon. Locate the primary alcohol and decide if is pointing up or down.