receptor

(reh-SEP-ter) A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific physiologic effect in the cell.

A trans-membrane protein located in the plasma membrane that can bind with a ligand on the extracellular surface, as a result of which it induces a change in activity on the cytoplasmic surface. More generally, a site in a molecule that allows the binding of a ligand.

A location where environmental resources such as air concentration or noise level are evaluated (e.g., property boundaries, residences, schools, hospitals, libraries).