Aldose sugar is converted to ketose sugar by
a. Carbohydrates are Aldehyde (Aldose) or ketone (ketoses) derivatives of the polyhydric alcohol
b. Aldose-Ketose-Isomerism → Fructose has the same molecular formula as glucose but differs in its structural formula since there is a potential keto group in position 2 the anomeric carbon of fructose whereas Aldehyde gp at 1 position in glucose.
Epimers (of monosaccharides) →Isomers differing as a result of variations in configuration of the —OH and —H on carbon atom 2,3, and 4 of glucose are known as Epimers. Eg. Biologically most important Epimers of glucose are Mannose and galactose, formed by epimerization at carbon 2 and 4, respectively.