Question 23.6: Another common disaccharide is lactose, the sugar found in m...

Another common disaccharide is lactose, the sugar found in milk. Lactose is a dimer of glucose and galactose, a monosaccharide that is identical to glucose except that the positions of the H and OH groups at carbon atom 4 are switched.

a Draw the structure of β-galactose.

b Draw the structure of lactose, which is broken down by the enzyme lactase to give equimolar amounts of β-galactose and β-glucose. Linkage occurs between carbon atom 1 of galactose and 4 of glucose.