AP BIOLOGY

Detailed explanation-1: -Small, hydrophobic ligands can pass through the plasma membrane and bind to intracellular receptors in the nucleus or cytoplasm.

Detailed explanation-2: -Lipid soluble cell signaling molecules bind to receptors that are in the cytoplasm while water-soluble cell signaling molecules bind to receptors at the cell surface membrane.

Detailed explanation-3: -1. All lipid soluble ligands use intracellular receptors–Steroids, thyroxine (TH), retinoids (vitamin A), and vitamin D.

Detailed explanation-4: -Molecules that are nonpolar, such as steroids, diffuse across the cell membrane and bind to internal receptors. In turn, the receptor-ligand complex moves to the nucleus and interacts with cellular DNA. This changes how a gene is expressed. Polar ligands, on the other hand, interact with membrane receptor protein.