Glucose isomer model. Molecular model of the alpha form of the hexose sugar glucose (C6H12O6), also known as alpha-glucopyranose. Glucopyranose has five carbon atoms (black) and one oxygen atom (red) in a ring, with an additional asymmetric carbon atom. Oxygen and hydrogen atoms (white) are bonded to each carbon atom. The position of an oxygen-hydrogen group relative to the carbon ring determines whether the molecule is the alpha or beta isomer of glucopyranose. Glucose is found in many plants and is a normal constituent of blood. It is widely used in the confectionary industry as a sweetener.