what ways are quorum sensing and the two component signaling system in bacteria similar? First we will see What is quorum sensing (QS). QS is a cell to cell communication in bacteria that involve signaling molecules or autoinducers (AIs). AIs come in different forms depending on bacterial species. As one would expect, the molecular mechanism of QS is dependent on species, but there are four main characteristics that govern all QS systems: At low bacterial cell density (LBCD), AIs diffuse away and their cellular concentration is approximately the same as the environment. At high bacterial cell density (HBCD), there is a cumulative production of AIs, which leads to a local high (environment) concentration. This is detected by the cells which in turn trigger different kinds of responses. AIs are detected by receptors that are either transmembrane molecules or are present in the cytoplasm. Detection of AIs leads to further production of AIs (feed forward loop) in addition to activating other genes. Qouram sensing and two component signaling system are inter connected and we will check how it is connected: Cell-density-dependent gene expression appears to be widely spread in bacteria. This quorum-sensing phenomenon has been well established in Gram-negative bacteria, where N-acyl homoserine lactones are the diffusible communication molecules that modulate cell- density-dependent phenotypes. Similarly, a variety of processes are known to be regulated in a cell-density- or growth-phase-dependent manner in Gram-positive bacteria. Examples of such quorum-sensing modes in Gram-positive bacteria are the development of genetic competence in Bacillus subtilis andStreptococcus pneumoniae, the virulence response in Staphylococcus aureus, and the production of antimicrobial peptides by several species of Gram-positive bacteria including lactic acid bacteria. Cell-density-dependent regulatory modes in these systems appear to follow a common theme, in which the signal molecule is a post-translationally processed peptide that is secreted by a dedicated ATP-binding-cassette exporter. This secreted peptide pheromone functions as the input signal for a specific sensor component of a two-component signal-transduction system. Moreover, genetic linkage of the common elements involved results in autoregulation of peptide-pheromone production. What advantages would an enzyme coupled receptor have over a G-coupled receptor? To understand the advantage of Enzyme-linked receptors over G-Protein Linked Receptors, we have to see how these both types of receptors function in cellular level. G-Protein Linked Receptors G-protein-linked receptors bind a ligand and activate a membrane protein called a G-protein. The activated G-protein then interacts with either an ion channel or an enzyme in the membrane. All G-protein-linked receptors have seven transmembrane domains, but each receptor has its own specific extracellular domain and G-protein-binding site. Cell signaling using G.

1. what ways are quorum sensing and the two component signaling system in bacteria similar?
First we will see What is quorum sensing (QS). QS is a cell to cell communication in bacteria
that involve signaling molecules or autoinducers (AIs).
AIs come in different forms depending on bacterial species.
As one would expect, the molecular mechanism of QS is dependent on species, but there are four
main characteristics that govern all QS systems:
At low bacterial cell density (LBCD), AIs diffuse away and their cellular concentration is
approximately the same as the environment.
At high bacterial cell density (HBCD), there is a cumulative production of AIs, which leads to a
local high (environment) concentration. This is detected by the cells which in turn trigger
different kinds of responses.
AIs are detected by receptors that are either transmembrane molecules or are present in the
cytoplasm.
Detection of AIs leads to further production of AIs (feed forward loop) in addition to activating
other genes.
Qouram sensing and two component signaling system are inter connected and we will check how
it is connected: Cell-density-dependent gene expression appears to be widely spread in bacteria.
This quorum-sensing phenomenon has been well established in Gram-negative bacteria, where
N-acyl homoserine lactones are the diffusible communication molecules that modulate cell-
density-dependent phenotypes. Similarly, a variety of processes are known to be regulated in a
cell-density- or growth-phase-dependent manner in Gram-positive bacteria. Examples of such
quorum-sensing modes in Gram-positive bacteria are the development of genetic competence in
Bacillus subtilis andStreptococcus pneumoniae, the virulence response in Staphylococcus aureus,
and the production of antimicrobial peptides by several species of Gram-positive bacteria
including lactic acid bacteria. Cell-density-dependent regulatory modes in these systems appear
to follow a common theme, in which the signal molecule is a post-translationally processed
peptide that is secreted by a dedicated ATP-binding-cassette exporter. This secreted peptide
pheromone functions as the input signal for a specific sensor component of a two-component
signal-transduction system. Moreover, genetic linkage of the common elements involved results
in autoregulation of peptide-pheromone production.
What advantages would an enzyme coupled receptor have over a G-coupled receptor?
To understand the advantage of Enzyme-linked receptors over G-Protein Linked Receptors, we
have to see how these both types of receptors function in cellular level.
G-Protein Linked Receptors
G-protein-linked receptors bind a ligand and activate a membrane protein called a G-protein. The

2. activated G-protein then interacts with either an ion channel or an enzyme in the membrane. All
G-protein-linked receptors have seven transmembrane domains, but each receptor has its own
specific extracellular domain and G-protein-binding site.
Cell signaling using G-protein-linked receptors occurs as a cyclic series of events. Before the
ligand binds, the inactive G-protein can bind to a newly-revealed site on the receptor specific for
its binding. Once the G-protein binds to the receptor, the resultant shape change activates the G-
protein, which releases GDP and picks up GTP. The subunits of the G-protein then split into the
subunit and the subunit. One or both of these G-protein fragments may be able to activate other
proteins as a result. Later, the GTP on the active subunit of the G-protein is hydrolyzed to GDP
and the subunit is deactivated. The subunits re-associates to form the inactive G-protein, and the
cycle starts over .
Examples are : Muscarinic acetylcholine receptors; beta-Adrenoceptors; Dopamine receptors;
Serotonin receptors; Opioid receptors
Enzyme-Linked Receptors
Enzyme-linked receptors are cell-surface receptors with intracellular domains that are associated
with an enzyme. In some cases, the intracellular domain of the receptor itself is an enzyme or the
enzyme-linked receptor has an intracellular domain that interacts directly with an enzyme.
Main advantage is The enzyme-linked receptors normally have large extracellular and
intracellular domains, but the membrane-spanning region consists of a single alpha-helical region
of the peptide strand.
When a ligand binds to the extracellular domain, a signal is transferred through the membrane
and activates the enzyme, which sets off a chain of events within the cell that eventually leads to
a response.
An example of this type of enzyme-linked receptor is the tyrosine kinase receptor. The tyrosine
kinase receptor transfers phosphate groups to tyrosine molecules. Signaling molecules bind to
the extracellular domain of two nearby tyrosine kinase receptors, which then dimerize.
Phosphates are then added to tyrosine residues on the intracellular domain of the receptors and
can then transmit the signal to the next messenger within the cytoplasm.
Similarly to the G-protein coupled receptors, enzyme-linked receptor is a transmembrane protein
with a ligand-binding domain on the outer surface of the plasma membrane. The cytoplasmic
domain that is associated with the trimeric G protein instead, but I directly related to the enzyme
or enzyme activity of internal or cytoplasmic domain of them. Meanwhile, G protein-coupled
receptors with seven transmembrane segments, each subunit of the enzyme-coupled receptor,
usually one is present.
Solution

3. what ways are quorum sensing and the two component signaling system in bacteria similar?
First we will see What is quorum sensing (QS). QS is a cell to cell communication in bacteria
that involve signaling molecules or autoinducers (AIs).
AIs come in different forms depending on bacterial species.
As one would expect, the molecular mechanism of QS is dependent on species, but there are four
main characteristics that govern all QS systems:
At low bacterial cell density (LBCD), AIs diffuse away and their cellular concentration is
approximately the same as the environment.
At high bacterial cell density (HBCD), there is a cumulative production of AIs, which leads to a
local high (environment) concentration. This is detected by the cells which in turn trigger
different kinds of responses.
AIs are detected by receptors that are either transmembrane molecules or are present in the
cytoplasm.
Detection of AIs leads to further production of AIs (feed forward loop) in addition to activating
other genes.
Qouram sensing and two component signaling system are inter connected and we will check how
it is connected: Cell-density-dependent gene expression appears to be widely spread in bacteria.
This quorum-sensing phenomenon has been well established in Gram-negative bacteria, where
N-acyl homoserine lactones are the diffusible communication molecules that modulate cell-
density-dependent phenotypes. Similarly, a variety of processes are known to be regulated in a
cell-density- or growth-phase-dependent manner in Gram-positive bacteria. Examples of such
quorum-sensing modes in Gram-positive bacteria are the development of genetic competence in
Bacillus subtilis andStreptococcus pneumoniae, the virulence response in Staphylococcus aureus,
and the production of antimicrobial peptides by several species of Gram-positive bacteria
including lactic acid bacteria. Cell-density-dependent regulatory modes in these systems appear
to follow a common theme, in which the signal molecule is a post-translationally processed
peptide that is secreted by a dedicated ATP-binding-cassette exporter. This secreted peptide
pheromone functions as the input signal for a specific sensor component of a two-component
signal-transduction system. Moreover, genetic linkage of the common elements involved results
in autoregulation of peptide-pheromone production.
What advantages would an enzyme coupled receptor have over a G-coupled receptor?
To understand the advantage of Enzyme-linked receptors over G-Protein Linked Receptors, we
have to see how these both types of receptors function in cellular level.
G-Protein Linked Receptors
G-protein-linked receptors bind a ligand and activate a membrane protein called a G-protein. The

4. activated G-protein then interacts with either an ion channel or an enzyme in the membrane. All
G-protein-linked receptors have seven transmembrane domains, but each receptor has its own
specific extracellular domain and G-protein-binding site.
Cell signaling using G-protein-linked receptors occurs as a cyclic series of events. Before the
ligand binds, the inactive G-protein can bind to a newly-revealed site on the receptor specific for
its binding. Once the G-protein binds to the receptor, the resultant shape change activates the G-
protein, which releases GDP and picks up GTP. The subunits of the G-protein then split into the
subunit and the subunit. One or both of these G-protein fragments may be able to activate other
proteins as a result. Later, the GTP on the active subunit of the G-protein is hydrolyzed to GDP
and the subunit is deactivated. The subunits re-associates to form the inactive G-protein, and the
cycle starts over .
Examples are : Muscarinic acetylcholine receptors; beta-Adrenoceptors; Dopamine receptors;
Serotonin receptors; Opioid receptors
Enzyme-Linked Receptors
Enzyme-linked receptors are cell-surface receptors with intracellular domains that are associated
with an enzyme. In some cases, the intracellular domain of the receptor itself is an enzyme or the
enzyme-linked receptor has an intracellular domain that interacts directly with an enzyme.
Main advantage is The enzyme-linked receptors normally have large extracellular and
intracellular domains, but the membrane-spanning region consists of a single alpha-helical region
of the peptide strand.
When a ligand binds to the extracellular domain, a signal is transferred through the membrane
and activates the enzyme, which sets off a chain of events within the cell that eventually leads to
a response.
An example of this type of enzyme-linked receptor is the tyrosine kinase receptor. The tyrosine
kinase receptor transfers phosphate groups to tyrosine molecules. Signaling molecules bind to
the extracellular domain of two nearby tyrosine kinase receptors, which then dimerize.
Phosphates are then added to tyrosine residues on the intracellular domain of the receptors and
can then transmit the signal to the next messenger within the cytoplasm.
Similarly to the G-protein coupled receptors, enzyme-linked receptor is a transmembrane protein
with a ligand-binding domain on the outer surface of the plasma membrane. The cytoplasmic
domain that is associated with the trimeric G protein instead, but I directly related to the enzyme
or enzyme activity of internal or cytoplasmic domain of them. Meanwhile, G protein-coupled
receptors with seven transmembrane segments, each subunit of the enzyme-coupled receptor,
usually one is present.