20.8: Simple Sugars
- Page ID
- 49612
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A careful consideration of the geometry of this structure reveals that not one but two cyclic structures are possible. These are called α- and β-glucose and are shown in Figure \(\PageIndex{2}\). In the β form the C—O bond on carbon atom 1 (shown in dark color) is parallel to the C—O bond on carbon atom 4, while in the α form these two bonds are at an angle of 180° – 109.5° = 70.5°. This geometric difference may seem relatively trivial, but it turns out to be important when glucose molecules are used as building blocks to form larger entities.