B2.1.9

• Glycoproteins are conjugated proteins with carbohydrate as the non-polypeptide component. They are a component of the membrane with the protein embedded in the membrane and the carbohydrate projecting out to the exterior.
• Glycolipids are molecules consisting of carbohydrates linked to lipids. They occur in the plasma membrane of all eukaryotic cells with the attached carbohydrate projecting outwards to the extracellular environment.
• Glycoproteins have the role of cell-to-cell recognition.
• Glycolipids have a role in cell recognition. They help the immune system to distinguish between self and non-self cells, so pathogens and foreign tissue can be recognised and destroyed.
• Glycoproteins and Glycolipids together form a carbohydrate-rich layer on the outer face of the membrane. This layer is called the glycocalyx. The glycocalyx of adjacent cells can fuse which binds the cells together.