This group of glycoproteins, glycolipids and proteoglycans has many roles, not all of which have been identified. The glycocalyx is known however to contribute to cell membrane rigidity and to increase cell adherence.
The membrane constituents of the glycocalyx are also involved in mechanisms of cellular identity and recognition. They are responsible for the ABO blood group system.
Diagram of the plasma membrane. The carbohydrates, glycoproteins and proteoglycans making up the glycocalyx are shown in red. © F. Boumphrey, Wikimedia CC by-sa 3.0