(i) D Glucose (Dextrorotatory): If the hydroxyl (OH) group is attached to the right side of the 5th carbon of glucose.
It is called dextrorotatory or D glucose. Its rotation direction is to the right of the chiral center. It is a light activator. All natural glucose is D glucose. Dr. Siddique Publications
(ii) L Glucose (Laevorotatory): If the hydroxyl (OH) group is attached to the left side of the 5th carbon of glucose, it is called Laevorotatory or L glucose. Its rotation direction is to the left of the chiral center. It is a light activator. L-glucose is synthetically produced for use in diabetes medication and endoscopy. (The center along which the carbon molecules are linked is called the chiral center). Dr. Siddique Publications
(iii) α-D glucose and β-D glucose: Carbon 1 of glucose forms an oxygen bridge near carbon 5. A ring structure is formed as a result. An -OH group is generated due to the ring structure. If the -OH group is below the 1st carbon of glucose, it is called α-D glucose and if it is above the 1st carbon of glucose, it is called β-D glucose. α-glucose forms starch and β-glucose forms cellulose. D glucose is always present in the plant body.