If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
AP Bio: IST‑3 (EU), IST‑3.C (LO), IST‑3.C.1 (EK), IST‑3.C.2 (EK), IST‑3.D (LO), IST‑3.D.1 (EK), IST‑3.D.2 (EK), IST‑3.E (LO), IST‑3.E.1 (EK)
Types of signaling molecules and the receptors they bind to on target cells. Intracellular receptors, ligand-gated ion channels, G protein-coupled receptors, and receptor tyrosine kinases.
Sort by:
Biology is brought to you with support from the Amgen Foundation