Glycolipid
Encyclopedia
Glycolipids are lipids with a carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...

 attached. Their role is to provide energy
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...

 and also serve as markers
Genetic marker
A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify cells, individuals or species. It can be described as a variation that can be observed...

 for cellular
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 recognition.

Metabolism

They occur where a carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...

 chain is associated with phospholipid
Phospholipid
Phospholipids are a class of lipids that are a major component of all cell membranes as they can form lipid bilayers. Most phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline; one exception to this rule is sphingomyelin, which is derived from...

s on the exoplasmic surface of the cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

  membrane
Biological membrane
A biological membrane or biomembrane is an enclosing or separatingmembrane that acts as a selective barrier, within or around a cell. It consists of a lipid bilayer with embedded proteins that may constitute close to 50% of membrane content...

. The carbohydrates are found on the outer surface of all eukaryotic cell membranes. The carbohydrate structure of the glycolipid is controlled by the glycosyltransferases that add the lipids and glycosylhydrolases that modify the glycan after addition.

They extend from the phospholipid bilayer into the aqueous environment outside the cell where it acts as a recognition site for specific chemicals as well as helping to maintain the stability of the membrane and attaching cells to one another to form tissues
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

.

Sphingolipidoses
Sphingolipidoses
-Accumulated products:* Gangliosides: Gangliosidosis** GM1 gangliosidoses** GM2 gangliosidoses*** Tay-Sachs disease*** Sandhoff disease* Glycolipids** Fabry's disease** Krabbe disease** Metachromatic leukodystrophy*Glucocerebrosides**Gaucher's disease...

 can be associated with defects in metabolism.

Types of glycolipids

The following is an incomplete listing of glycolipid types.
  • Glyceroglycolipids
    • Galactolipid
      Galactolipid
      Galactolipids are a type of glycolipid whose sugar group is galactose. They're different from glycosphingolipids in that they do not have nitrogen in their composition....

      s
    • Sulfolipid
      Sulfolipid
      Sulfolipids are a class of lipids which possess a sulfur-containing functional group. One of the most common consituents of sulfolipids is sulfoquinovose, which is acylated to form sulfoquinovosyl diacylglycerols. In plants, sulfolipids are important intermediates in the sulfur cycle....

      s (SQDG
      SQDG
      Sulfoquinovosyl diacylglycerols, abbreviated SQDG, are a class of sulfur-containing but phosphorus-free lipids found in many photosynthetic organisms.- Discovery, structure and chemical properties :...

      )
  • Glycosphingolipids
    • Cerebroside
      Cerebroside
      Cerebrosides is the common name for a group of glycosphingolipids called monoglycosylceramides which are important components in animal muscle and nerve cell membranes.They consist of a ceramide with a single sugar residue at the 1-hydroxyl moiety...

      s
      • Galactocerebroside
        Galactocerebroside
        A galactocerebroside is a type of cerebroside consisting of a ceramide with a galactose residue at the 1-hydroxyl moiety.The galactose is cleaved by galactosylceramidase....

        s
      • Glucocerebroside
        Glucocerebroside
        Glucocerebroside is any of the cerebrosides in which the monosaccharide head group is glucose.-Clinical significance:...

        s
        • Glucobicaranateoets
      • Sulfatide
        Sulfatide
        Sulfatides are a class of sulfated galactosylceramides synthesized primarily in the oligodendrocytes in the central nervous system. Sulfatides are a type of sulfolipid.-Clinical significance:...

        s
    • Ganglioside
      Ganglioside
      Ganglioside is a molecule composed of a glycosphingolipid with one or more sialic acids linked on the sugar chain. The 60+ known gangliosides differ mainly in the position and number of NANA residues.It is a component of the cell plasma membrane that modulates cell signal transduction events...

      s (the most complex animal glycolipids; contain negatively charged oligosacchrides with one or more sialic acid residues; more than 200 different gangliosides have been identified; they are most abundant in nerve cells)
    • Globoside
      Globoside
      A globoside is a type of glycosphingolipid with more than one sugars as the side chain . The sugars are usually a combination of N-Acetylgalactosamine, D-glucose or D-galactose. A glycosphingolipid that has only one sugar as the side chain is called a cerebroside.The side chain can be cleaved by...

      s
    • Glycophosphosphingolipids (complex glycophospholipids from fungi, including yeasts, and in plants, where they were originally called "phytoglycolipids" by Herbert Carter, et al., may comprise as complicated a set of compounds as the negatively charged gangliosides in animals. The head group of a glycolipid is composed of sugars.
  • Glycosylphosphatidylinositols
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