Receptor-Mediated Signal Transduction ystems CELL-SURFACE RECEPTORS plasma membrane cell-surface recepto Receptors Cell Surface Receptors; hydrophilic signal molecule Nuclear receptors INTRACELLULAR RECEPTORS small hydrophobic signal molecule carrier protein intracellular receptorReceptors: ⚫ Cell Surface Receptors; ⚫ Nuclear Receptors Receptor-Mediated Signal Transduction Systems