Pan-African flag - History. 1  The flag was created in 1920 by members of UNIA in response to the enormously popular 1900 coon song Every Race Has a Flag but the Coon. [4] which has been cited as one of the three songs that firmly established the term coon in the American vocabulary.
A ligand is any molecule that binds to a specific site on a protein or other molecule. In this case, the estrogen hormone 17-beta-estradiol is the ligand, and the estrogen receptor is the protein. Binding turns on, or activates, a hormone receptor.
The binding of neurotransmitters to receptors is often described using a lock and key metaphor. A âkey,â or neurotransmitter, neatly binds with a receptor âlockâ resulting in the propagation or dampening of the neural signal (also referred to as the action potential). Receptors, however, are not quite as specific as a single matching lock and key.