[Campbell Biology P.269] Which of the following statements most accurately highlights a key ... | Practice Question

Which of the following statements most accurately highlights a key difference between ligand-gated ion channels and intracellular receptors?

  • A: Ligand-gated ion channels primarily bind hydrophobic ligands, while intracellular receptors bind hydrophilic ligands.
  • B: Ligand-gated ion channels are located in the cytoplasm or nucleus, whereas intracellular receptors are embedded in the plasma membrane.
  • C: Ligand-gated ion channels directly regulate ion flow across the membrane, while intracellular receptors typically alter gene expression.
  • D: Both receptor types require ATP hydrolysis for ligand binding and activation.

Explanation

Ligand-gated ion channels are membrane proteins that form a pore, allowing specific ions to pass through when activated by a ligand, directly affecting ion concentrations and electrical signals. In contrast, intracellular receptors bind ligands that have crossed the plasma membrane, and the resulting hormone-receptor complex often acts as a transcription factor in the nucleus, directly altering gene expression. This represents their primary functional difference.