What interaction between oral bacteria is done by diffusable signaling?

• A. Biofilm formation
• B. Quorum sensing
• C. Contact independent interaction
• D. Horizontal gene transfer

Answer: (C)

Diffusible signaling that coordinates bacterial behavior is best described by quorum sensing. In this system, bacteria release signaling molecules called autoinducers into the surrounding environment. As the population grows, these molecules accumulate and reach a threshold concentration, at which point receptors detect them and trigger coordinated changes in gene expression across the community. This mechanism explains how oral bacteria synchronize activities like surface attachment, matrix production, and biofilm maturation without direct cell-to-cell contact. While the broad idea of contact-independent signaling covers many diffusible signals, quorum sensing is the specific process by which bacteria interpret those signals to regulate group behavior. Horizontal gene transfer is a separate process involving genetic exchange, not signaling-driven coordination.