PRE LAB 2 QUORUM SENSING

Question 1

She is the proponent of quorum sensing

Answer 1

Bonnie Bassler

Question 2

Her study focus on (1)

Molecular mechanism of the bacteria used for (2)

Answer 2

(1) cell-to-cell communication of bacteria

(2) Intercellular communication

Question 3

Their goal is to understand how bacteria _______________

How the integration and processing of this information results in the precise ________ within the species involved

Answer 3

detect multiple environmental cues

regulation of gene expression

Question 4

how bacteria communicate with one another?

Answer 4

secretion of signaling molecules - autoinducers or ligands resulting in regulation of gene expression and change of behavior or physiological processes

Question 5

In quorum sensing bacteria assess the
population density by detecting the
________ of particular
autoinducers.

Answer 5

concentration

Question 6

In quorum sensing, it can be observed
the _____________

Answer 6

strength in number

Question 7

Explain the sensory information flow of lux genes

Answer 7

1. signal/autoinducer binds to the membrane-boun receptor
2. attraction of RNA polymerase
3. induce transcription, translation and production of protein
4. create bioluminescence

Question 8

two types of communication

Answer 8

intercellular - across different species
intracellular - two members of the same kin

Question 9

Autoinducer varies depending on its

Answer 9

size, polarity and peptide base molecule

Question 10

example of hydrophobic autoinducer

Answer 10

AHL- Acyl-homoserine lactone

Question 11

what happens to autoinducer at low and high density

Answer 11

low- diffuse away from the cell
high- bind to receptors, regulate transcription of gene, gene produce autoinducers — positive feedback loop

Question 12

T or F
Free living V. fischeri can produce their own luciferase

Answer 12

false - only those attached to a host can produce bioluminescence

Question 13

Quorum sensing determines whether
the bacteria should produce __________
once they are attached to the host

How?

Answer 13

luciferase
if it sense that the host is threatened cell-to-cell comm occurs to trigger its production

Question 14

coding sequence that encodes the by-product of proteins

Answer 14

Lux operon

Question 15

lux operon is consists of two proteins

Answer 15

LuxI - produces autoinducer
LuxR - transcriptional activator triggered by AI to recruit the RNA polymerase to transcribe

Question 16

the reaction between LuxI and LuxR is called

Answer 16

positive inducible regulation

Question 17

what happens to the lux genes at high density of AI

Answer 17

RNA Polymerase transcribe operons (LuxA and LuxB) with the LuxI and LuxCDABE

Question 18

the operon that is responsible for light emission is _____ to produce ____

Answer 18

LuxA and Lux B
luciferase

Question 19

what happens if bacterial concentration is low

Answer 19

transcriptionof the operon will be low, levels of LuxI will be low too

Question 20

When autoinducers are now ________, it
will trigger the transcriptional
activators, where RNA polymerase is
present, and then transcription will
begin

Answer 20

abundant