The members all have seven different protein segments that cross the membrane, and they transmit signals inside the cell through a type of protein called a G protein. When its ligand is not present, a G protein-coupled receptor waits at the plasma membrane in an inactive state.
Its just like Water drops on a pine needle or on anything else, Cohesion is when water is attracted to water. Therefor its Adhesion, because that's when water is attracted to other things or substances.