molecule (most commonly on the surface of a cell) which reacts to a substance which stimulates it. This leads
to further biochemical changes within the cell itself.
Proteins in, on, or traversing the cell membrane that recognize and bind to specific molecules in the
surrounding fluid. The binding may serve to transport molecules into the cell's interior or to signal
the cell to respond in some way. Examples of such receptors include the alpha and beta receptors on blood vessels;
the beta-1 receptor of the heart; the histamine receptor on
specific receptors. See also : ,