How Is The Glucose The Most Important Hexose?
Glucose is the most important hexose, because all hexose sugars in the body have to be converted into glucose prior to their metabolism. Glucose can exist in two forms: Straight chain form Ring form The ring structure of glucose exists in aqueous solution. In the straight chain form, an aldehyde group is exposed and many tests for glucose (and other reducing sugars) rely on this exposed aldehyde group being present in solution. In these test, using Benedict’s or Fehling solution. The aldehyde (-CHO) group is oxidized to a carboxylic acid (-COOH) group. The Cu2+ (cupric) or copper ion present in the tests solution is reducing to cu ions or copper. The reducing agents in the reaction are the sugar, hence the name reducing sugars. Such reaction can be adapted to test for glucose either in urine or blood. Lactose is a hexose sugar present in milk; it is therefore sometimes called’ milk sugar’. A small amount of it occurs in the blood of a lactating (milk giving) mother, who has just given
