Glycolipids & Glycoproteins (DP IB Biology)

Glycoproteins & Glycolipids

• Glycoproteins are cell membrane proteins that have a carbohydrate chain attached on the extracellular side

  • Extracellular = outside cells

• Glycolipids are lipids with carbohydrate chains attached, also located on the outer surface of cell membranes

The function of glycoproteins and glycolipids

• The carbohydrate chain enables them to act as receptor molecules

  • This allows them to bind with substances at the cell surface

  • Receptor types include:

    • Signalling receptors which bind to hormones and neurotransmitters

    • Receptors involved in endocytosis

    • Receptors involved in cell adhesion and stabilisation

      • Cell adhesion allows cells to attach to each other to form tissues

• Some act as cell markers, or antigens, for cell identification

  • E.g. this allows the immune system to determine whether or not a cell belongs in the body, or whether it is a pathogen

Glycoproteins and glycolipids diagram

Glycoproteins are carbohydrate chains attached to membrane proteins and glycolipids are carbohydrate chains attached to the lipid element of the cell membrane