Cell signaling Original Scenario-Based Download PDF

Questions

1. 1.

   During an abyssal trench expedition, researchers isolate Chronoamoeba, a single-celled organism that emits a brilliant pulse of bioluminescent light upon detecting trace environmental cues. Biochemical analyses reveal that the binding of a single peptide ligand to an external membrane receptor triggers the activation of over one hundred thousand cytosolic light-producing enzymes within milliseconds, despite the ligand itself never entering the cell. Which mechanism in the cell signaling pathway directly accounts for this massive magnification of the initial stimulus?

   • A) Direct translocation of the intact receptor-ligand complex into the nucleus to induce instantaneous gene expression
   • B) Enzymatic amplification through a multistep transduction cascade where each active component activates multiple downstream targets
   • C) Passive opening of broad membrane pores that allow thousands of identical extracellular pheromones to flood the cytoplasm
   • D) Rapid hydrolytic breakdown of the plasma membrane bilayer into nucleotide triphosphates that fuel the light-emitting enzymes