What interaction between oral bacteria is done by physical contact?

What interaction between oral bacteria is done by physical contact?

• A. Quorum sensing
• B. Diffusible signaling
• C. Contact independent interaction
• D. Contact dependent interaction

Answer: (D)

The main concept is distinguishing how oral bacteria interact: some interactions occur via signals that diffuse through the environment, while others require direct cell-to-cell contact. Quorum sensing and diffusible signaling rely on molecules released by cells that travel through the medium to influence distant neighbors, so they are contact-independent. In contrast, contact-dependent interactions need physical contact between cells to transfer signals or deliver effectors, enabling direct influence only when bacteria touch or are tightly apposed. In the mouth, this includes surface-mediated adhesion and delivery of localized factors via contact-dependent systems, which is why the interaction accomplished by physical contact is the one that requires direct cell contact.

The main concept is distinguishing how oral bacteria interact: some interactions occur via signals that diffuse through the environment, while others require direct cell-to-cell contact. Quorum sensing and diffusible signaling rely on molecules released by cells that travel through the medium to influence distant neighbors, so they are contact-independent. In contrast, contact-dependent interactions need physical contact between cells to transfer signals or deliver effectors, enabling direct influence only when bacteria touch or are tightly apposed. In the mouth, this includes surface-mediated adhesion and delivery of localized factors via contact-dependent systems, which is why the interaction accomplished by physical contact is the one that requires direct cell contact.