I: Quorum Sensing

Question 1

Why is quorum sensing used by bacteria

Answer 1

to assess pop density. at high pop density, results in coordination of transcription of specific genes

Question 2

What are signalling molecules

Answer 2

each species synthesis specific signalling molecules called autoinducer

Question 3

Describe autoinducers in gram -ive bacteria

Answer 3

can diffuse freely in/out of cell.

Question 4

How is the transciption of specific genes triggers

Answer 4

by [high] of autoinducer inside cytoplasm

Question 5

What is the gram of Vibrio fischeria, where is it found, and symbiont in what

Answer 5

gram -ive, lives freely in salt water. And lives as symbiont in the light organs of some fish and squid

Question 6

Describe autoinducers in freely living Vibrio fischeria

Answer 6

synthesizes autoinducer that will diffuse down its [gradient] and out of cell. in freely living bacteria, [of] the autoinducer inside cell will be low

Question 7

What happens if Vibrio fischeri is living in contained environment of a light organ

Answer 7

will grow and pop increases. [of] autoindicer outside the cell increases. rate of diffusion is reduced and intracellular [increases]

Question 8

What is regulated by quorum sensing (2)

Answer 8

expression of EPS and flagella in a biofilm

Question 9

Once the rate of diffusion is reduced, what happens next

Answer 9

results in expression of lux genes which convert chemical nrg to light. light helps animal hide from predators