what binds to a receptor
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 cellâs fatty outer membrane. The membraneâs fat layers impede water-friendly hormones from passing through but allow fat-derived hormones to readily enter the cell.
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.