Cell Coat:

• A distinct layer of glycocalyx is observed in the outer surface of cells in many animals and protistans.
• Fibrous and made up of oligosaccharides- which are actually part of plasma membrane.
• In some cases cell coat is thickened by deposition of calcium, silicon and other salts.
• Useful in recognition between microbe and body cell by WBCs and involved in histocompatibility.
• Blood grouping is based on specific antigens present in the cell coat of erythrocytes.