Carbohydrates

Compare Alpha and Beta Glucose in the Chair Structures:

The position of the -OH group on the anomeric carbon (#1) is an important distinction for carbohydrate chemistry.

The Beta position is defined as the -OH being on the same side of the ring as the C # 6. In the chair structure this results in a horizontal projection.

The Alpha position is defined as the -OH being on the opposite side of the ring as the C # 6. In the chair structure this results in a downward projection.

The alpha and beta label is not applied to any other carbon - only the anomeric carbon, in this case # 1.

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Ref.
http://www.elmhurst.edu/~chm/vchembook/543glucose.html