The most important factor determining which type of receptor a signal molecule will bind to is
A) the lipid solubility of the ligand.
B) the size of the ligand.
C) the size of the receptor molecule.
D) the location of the receptor molecule.

Question

Quizplus · Accepted Answer

The lipid solubility of the ligand is the most important factor because it determines whether the ligand can penetrate the plasma membrane and reach intracellular receptors or needs to bind to transmembrane receptors on the cell surface. Small, hydrophobic ligands like steroid hormones can cross the plasma membrane and bind to intracellular receptors, while larger, hydrophilic ligands like peptide hormones must bind to transmembrane receptors on the cell surface. Size, location, and the size of the receptor molecule may be important factors for receptor-ligand binding, but they are not the most important determining factor.

The Most Important Factor Determining Which Type of Receptor a Signal