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No matter how many times it is demonstrated, it’s still difficult to envision bacteria as social creatures with the ability to communicate. These simple, tiny, single celled prokaryotes use a signaling system called ‘quorum sensing” to alter their behavior to suit the size of their population. What this means is that the bacteria actually ‘know” how many of them are present at that particular time. This “knowledge” is carried in small molecules that the lead bacteria release and the other bacteria then pick up by diffusion through their cell membrane. Previous research has shown that bacteria use quorum sensing in a number of different ways. Some bacteria use it to monitor population size in a host organism. Once they get to a certain number, they release disease causing chemicals and overwhelm their hosts’ immune system.

The latest study involves using chemicals that mimic quorum sensing in order to control growth of pathogenic bacteria such as salmonella or shingella. Many of these strains are resistant to most antibiotics, but when given the quorum sensing chemical mimics the bacteria stay “tame” and do not give off their pathogenic chemicals, thus allowing the body’s own immune system to wipe out the bacteria.

Which statement best describes quorum sensing in bacteria?


The ability of bacteria to destroy the hosts’ immune system.


The ability of bacteria to communicate and respond to their environment.


The ability of bacteria to become multicellular and carry out complex processes.


The ability of bacteria to diffuse nutrients inside their cells.

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