what is the chemical which binds specifically to plasma membrane receptors
CHAPTER 24 Plasma Membrane Receptors Cells use about 20 different families of receptor proteins to detect and respond to the myriad of incoming chemical and physical stimuli (Appendix 24-1). Most receptors are plasma membrane proteins that interact with chemical ligands or are stimulated by physical events such as light absorption. A few chemical stimuli, including steroid hormones and the gas nitric oxide, cross the plasma membrane and bind receptors inside the cell. Figure 24-1 sixteen classes of receptors with signal transduction mechanisms.