Hydrophilic signal molecules typically bind to
- A
Ribosomal binding subunits
- Bcheck_circle
Cell-surface (membrane) receptors
- C
Intracellular nuclear receptors
- D
Mitochondrial inner membrane
Explanation
Hydrophilic ligands cannot cross the membrane and bind receptors on the outside. Hydrophobic ligands (e.g., steroids) cross the membrane and bind intracellular receptors.