UDP-galactose is a nucleotide sugar that plays a crucial role in the metabolism of carbohydrates. It is formed from galactose, a simple sugar, and uridine diphosphate (UDP). This compound is essential for the synthesis of glycoproteins and glycolipids, which are important for cell structure and function. In the body, UDP-galactose is involved in the conversion of galactose into glucose, a vital energy source. It also participates in the biosynthesis of lactose, the sugar found in milk, and contributes to the formation of various polysaccharides.