noun, plural: glyceroglycolipids
A glycolipid is a glycoconjugate comprised of carbohydrate and lipid moieties. Examples of glycolipids are glycosphingolipids and glyceroglycolipids. A glyceroglycolipid is comprised of an acetylated or non-acetylated glycerol backbone and at least one fatty acid. It is often found as a component of biological membranes with photosynthetic functions (e.g. chloroplasts). Glyceroglycolipids include the galactolipids and the sulfolipids.
A galactolipid is a type of glyceroglycolipid that has galactose as the sugar component. The galactose is attached to a glycerol lipid. They occur naturally in the chloroplast membranes of photosynthetic eukaryotes (e.g. plants and photosynthetic algae). Apart from eukaryotes, photosynthetic bacteria also have galactolipids in their membranes. The predominant galactolipids in photosynthetic organisms are monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG).
A sulfolipid is a glyceroglycolipid that has a carbohydrate moiety wherein the functional group contains sulfur. The carbohydrate constituent is attached to a lipid. Example of a sulfolipid is sulfoquinovosyl diacylglycerol, which is involved in the plant's sulfur cycle.
Glyceroglycolipids can also be referred to, in particular, as glycerolipid glycans. Glycerolipid, per se, is a type of lipid comprised of a glycerol that is linked esterically to a fatty acid. Thus, glyceroglycolipids may also be regarded as a sub-class of glycerolipids.