Receptors and ligands Original Scenario-Based Download PDF

Questions

1. 1.

   A synthetic biologist designs a biosensing cellular probe, Astraea, to monitor deep-sea chemical plumes via fluorescent signaling cascades. Pathway 1 is engineered to detect a polar peptide toxin, whereas Pathway 2 is engineered to detect a nonpolar, lipid-soluble hydrocarbon pollutant. To ensure proper activation, the researcher must insert the receptors for these two target ligands into their appropriate cellular compartments. Which statement correctly predicts the structural localization and reception mechanism for these two distinct signaling pathways?

   • A) The receptor for Pathway 1 resides in the cytoplasm because peptides dissolve through the lipid bilayer, while Pathway 2 uses an integral membrane receptor.
   • B) The receptor for Pathway 2 must be an extracellular peripheral protein because nonpolar hydrocarbons are repelled by the hydrophobic core of the plasma membrane.
   • C) Both ligands bind non-specifically to the same cell-surface receptor because ligand-binding pockets do not distinguish between polar and nonpolar molecules.
   • D) The receptor for Pathway 1 will be an integral membrane protein with an extracellular binding site, whereas the receptor for Pathway 2 will be located intracellularly.