Quorum sensing Original Scenario-Based Download PDF

Questions

1. 1.

   In an underwater research dome, microbiologists study an engineered bacterial strain designed to produce a bright fluorescent glow during bio-remediation tasks. Individual cells constitutively secrete a small peptide autoinducer, yet fluorescence is observed only after thousands of cells accumulate within a confined microfluidic chamber. When researchers continuously flush the chamber with sterile broth to wash away the extracellular peptide without reducing the number of bacteria, the dense population immediately ceases glowing. Which statement best explains why washing away the secreted peptide prevents this synchronized cellular response?

   • A) Removing the extracellular peptide halts binary fission, preventing the cells from reaching the physical contact threshold needed for illumination.
   • B) The signaling peptide acts as a direct metabolic enzyme in the cytosol whose continuous intake is required to synthesize fluorescent pigments.
   • C) Constant flushing of the medium removes the carbon and energy sources necessary for cells to power active transport across their membrane.
   • D) The synchronized behavior depends on the local concentration of the signaling molecule reaching a critical threshold that alters target gene expression.