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The stereochemical designators alpha and beta refer specifically to the configuration of the hydroxyl (-OH) group attached to the anomeric carbon in carbohydrate molecules. The anomeric carbon is the carbon atom that was the carbonyl carbon (either aldehyde or ketone) in the open-chain form of the sugar.
In the cyclic form of the sugar, when it forms a ring, this anomeric carbon can exist in two different configurations based on the orientation of the hydroxyl group: if the hydroxyl group is on the opposite side of the ring from the CH2OH group in the case of a pyranose sugar, it is designated as beta; if it is on the same side, it is designated as alpha. This specific distinction means that alpha and beta configurations are related structurally but differ in their spatial arrangement, making them anomers of each other.
Anomers are a subtype of stereoisomers that differ in configuration specifically at the anomeric carbon. Thus, the correct answer relates directly to the classification of these two forms as distinct because of their differing orientations around a specific stereocenter, which is the anomeric carbon in this case.