Aldoses and Ketoses are classifications of monosaccharides according to carbonyl groups (C=O), hydroxyl groups (OH), and aldehydes and ketones. An aldehyde’s formula is R–C=O (C –H). This is translated as a single bond between 1 carbon atom and 1 hydrogen atom, and a double bond between that same carbon atom and an oxygen atom. If, in a monosaccharide, this aldehyde formula is present, and is at the beginning or end of the sugar molecule, then the sugar is classified as an aldose. A ketone’s formula is R-R–C=O, which can be translated as a double bond between an oxygen and carbon atom. If this formula is present in a monosaccharide, and is inside the sugar molecule, not on the ends, then that particular monosaccharide is characterized as a ketose. In a solution, usually an aqueous solution, the sugar molecule takes on a ring structure due to being an aldose or ketose. The monosaccharide, however, must have more than 5 carbon atoms in order for the reaction to occur. Aldehydes and ketones are produced by further oxidation of hydrocarbons after going through oxidation by alcohols and ethers.
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