Chapter 14 Flashcards
When arabinose is present in the environment, the AraC protein acts as a(n) ______________ for the E. coli ara operon.
activator
When there is no arabinose available in the environment, the AraC protein acts as a(n) ______________ for the E. coli ara operon.
repressor
If a set of genes is repressed in the presence of the controlling substance, it is referred to as __________ control.
negative
If a set of genes is induced in the presence of the controlling substance, it is referred to as __________ control.
positive
(T/F) The binding of arabinose to the AraC protein allows it to form a loop in the DNA upstream of the ara operon promoter.
False
(T/F) Two-component signal transduction systems are found in the Bacteria, but not in Archaea.
False
(T/F) The real inducer for the E. coli lac operon is allolactose produced by the action of permease on lactose.
False
(T/F) In the presence of both glucose and lactose, the lactose repressor is not bound to the operator and the genes of the lactose operon are expressed.
False
(T/F) Small RNAs that regulate translation by binding to the leader region of mRNAs are called antisense RNAs.
True
____________ is used to measure the amount of a chemoattractant encountered over time.
Methylation
(T/F) One way to regulate gene expression is through the production of different sigma factors. These cause RNA polymerase to bind to different sets of promoters, thereby altering the pattern of gene expression.
True
(T/F) Gene regulation during sporulation in Bacillus subtilis involves BOTH temporal and spatial control.
True
In order for high level expression of the E. coli lac operon to occur, a complex of catabolite activator protein and __________ must be bound to the DNA near the promoter.
cAMP
A collection of genes or operons controlled by a common regulatory protein is called a(n) ___________.
regulon
Regulation of gene expression serves to do all of the following except….
a.conserve energy and raw materials.
b.maintain balance between the amounts of various cell proteins.
C.adjust the activity of existing proteins in the cell.
d.adapt to long-term environmental change.
In two component regulatory systems, the response regulator typically receives a ____________ from the sensor kinase when it has been activated….
a.pyruvate group
B.phosphoryl group
c.acetyl group
d.methyl group
While standard two-component regulatory systems typically act to control gene transcription, phosphorelay systems can act either to control gene transcription or to control…..
a.translation.
B.protein activity.
c.DNA replication.
d.all of the choices.
The sensor kinase for the OmpF: OmpC two-component regulatory system is….
a.the OmpK protein.
B.the EnvZ protein.
c.the MicF RNA.
d.none of the choices.
The E. coli lac operon has ________ operator sequences….
a.one
b.two
C.three
d.four
So-called two-component regulatory systems…
a.include a sensor kinase and a response regulator.
b.play a key role in regulating sporulation in Bacillus.
c.play a key role in regulating the OmpF and OmpC porin proteins in E. coli.
D.all of the choices
If Escherichia coli is cultured in broth containing both glucose and lactose, it…
A.uses glucose preferentially until the supply is exhausted, then uses lactose.
b. uses lactose preferentially until the supply is exhausted, then uses glucose.
c. uses glucose and lactose simultaneously.
d. uses only the glucose (it cannot use lactose as a source of carbon).
__________ activate repressor proteins thereby decreasing the synthesis of certain enzymes….
a.Inducers
B.Corepressors
c.Effectors
d.Modulators
__________ alter repressor proteins thereby increasing the rate of transcription initiation…..
A.Inducers
b. Corepressors
c. Effectors
d. Modulators
______________ is used to control transcription of some anabolic pathways involved in amino acid biosynthesis….
A.Attenuation
b. Catabolite repression
c.Induction
d. All of the choices
When a repressor binds to the operator site on the DNA it normally…
A.inhibits the initiation of transcription.
b. reduces the rate of transcription.
c. terminates transcription that has already been initiated.
d.has no effect on transcription.
Enzymes that are expressed at a constant level all the time are said to be:
a.inducible.
b.repressible.
C.constitutive.
d.attenuated.
Which of the following is not a regulatory mechanism used to control the tryptophan operon in Escherichia coli?…
a.repression
B.catabolite repression
c.attenuation
d.all of the choices
Which of the following is not a regulatory mechanism used to control the lactose operon in Escherichia coli?…
a.induction
b.catabolite repression
C.attenuation
d.all of the choices
The site on the DNA to which a repressor protein binds is the __________….
a.operon
B.operator
c.promoter
d.regulator
When bound to the DNA, the repressor protein usually prevents attachment of the RNA polymerase to the __________….
a.operon
b.operator
C.promoter
d.regulator
he __________ is a factor-independent termination site found in the leader region of certain operons, which, under the influence of ribosome behavior, controls the continued transcription of that operon….
a.modulator
b.operator
C.attenuator
d.terminator
What is the key factor determining whether or not attenuation will occur when transcription of the E. coli trp operon has been initiated?..
a.The activity level of adenyl cyclase.
b.The trp operon repressor.
c.The level of tryptophan in the environment.
D.The level of trp-tRNA that is charged with tryptophan.
With the E. coli trp operon where both repression and attenuation occur, the extent of regulation achieved by repression is _____________ the extent of regulation achieved by attenuation….
a.the same as
b.less than
C.greater than
d.repression is not used in the regulation of the E. coli trp operon
The terminator versus anti-terminator function of the T box-based riboswitch used by Gram-positive bacteria to regulate amino acid-related genes is determined by…
A.the binding of the appropriate uncharged tRNA. b.the rate of leader peptide synthesis.
c. the binding of the T box binding protein.
d. the utilization of the appropriate sigma factor by RNA polymerase.
Most E. coli antisense RNAs work with a protein called ______ to regulate their target mRNAs…
a.CAP
b.MicF
C.Hfq
d.none of the choices
Posttranslational regulation occurs after a protein has been synthesized, and can occur by….
a.allosteric regulation. b.feedback inhibition. c.covalent modification. D.allosteric regulation and covalent modification are both means of regulation after translation is complete.
What term describes a set of genes that is controlled by a common regulatory protein?…
a.codon
B.regulon
c.transcription
d.operon
In some circumstances, when two different carbon sources are available, growth will occur first using one carbon source, then after a short lag period, growth will resume using the second carbon source. This process is called __________ growth…
a.biphasic
b.bimorphic
C.diauxic
d.dimorphic
The activity of adenyl cyclase is influenced by..
A.the phosphotransferase system.
b. the presence of lactose in the environment.
c. homoserine lactones.
d. none of the choices
An operon network that is under the control of a common regulatory protein while each operon is still also under the control of its own unique regulatory protein is most specifically referred to as a….
a.regulon.
b.webulon.
C.modulon.
d.complexon.
The standard or housekeeping sigma factor used most often by E. coli RNA polymerase under normal growth conditions is called sigma ___.
70
Acylhomoserine lactones used in quorum sensing regulate their own synthesis by a(n) ____________ system….
a. riboswitch
b. antisense
c. catabolite repression
D.autoinduction
The sensing of starvation that leads to sporulation in Bacillus subtilis is accomplished by a(n)…
a.small RNA.
B.sensor kinase.
c.response regulator.
d.quorum regulatory effector.
Cell-to-cell communication by quorum sensing has been shown to be important in the regulation of genes needed for…
a.virulence.
b.biofilm production.
c.plasmid transfer.
D.all of the choices.
