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.
Whether a hormone binds to a receptor inside or outside a cell depends on the chemical nature of the hormone and its compatibility with the cellâs fatty outer membrane. The membraneâs fat layers impede water-friendly hormones from passing through but allow fat-derived hormones to readily enter the cell.
A receptor is basically a protein in a cell (usually in a cell membrane, but doesn't have to be (eg. NO and steroid receptors). When a ligand (an agonist) meets the receptor, the protein changes its physical conformation, making it more or less likely to do something else, eg. catalyze something, open an ion channel. Antagonists bind to receptors like agonists, but without doing anything, effectively blocking them.