• Receptors are actually a protein in nature & their binding sites have different shapes, structures, & amino acid compositions ( main reason of proteinic nature).

• These receptors interact with several types of chemical messengers & they are selective & specific in their interaction with the messengers.

It is mainly due to their proteinic properties which allow the chemical messengers to bind to their binding sites and carry the message to one cell and communicate b/w cells (b/w 2 neurons & b/w neurons & muscles) which sometimes carry coded genetic information for the cell.