Galactolipid

Galactolipids are a type of glycolipid whose sugar group is galactose. They differ from glycosphingolipids in that they do not have nitrogen in their composition.
They are the main part of plant membrane lipids where they substitute phospholipids to conserve phosphate for other essential processes. These chloroplast membranes contain a high quantity of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG).