Galactose Pyranose Molecule Structure

Galactose has the chemical formula C₆H₁₂O₆. D-galactose is the linear form. It has a carbonyl group at C1 , forming an aldehyde, 6 carbon aldohexose reducing sugar. In humans and other mammals it occurs mainly as the 6 carbon ringed structure, beta-D-galactopyranose (as shown in the image) which combines with glucose to from the disaccharide lactose, or milk sugar. Note its only difference to glucose is the position of the "OH" group at the carbon 4 position. 

You can use our 3D Molecular Model Builder to illustrate galactose in any of its 5 forms. First choose the model style: "Orbit-flexible". Then choose which structure you want to view/build. Simply enter galactose for the linear molecule, note the carbonyl at carbon 6. Enter alpha-d-galactopyranose or beta-d-galactopyranose to view 6 member rings; alpha-d-galactofuranose or beta-d-galactofuranose for 5 member rings.