Deck 10: Molecular Regulation

Question 1

Which form of control is the most rapid?

A) alterations of DNA sequence
B) control of transcription
C) mRNA stability
D) translational control
E) posttranslational control

Answer 1

D

Question 2

Which is the favored carbon source of E. coli?

A) lactose
B) galactose
C) glucose
D) sucrose
E) fructose

Answer 2

C

Question 3

__________ analysis with the lactose operon showed that the area protected by the repressor overlaps the area protected by RNA polymerase.

A) PCR
B) DNA footprint
C) Agarose gel electrophoresis
D) PAGE
E) X-ray crystallography

Answer 3

B

Question 4

__________ is a general term to describe the degradation of an organic food source.

A) Metabolism
B) Anabolism
C) Constitutive
D) Catabolism
E) Inducible

Question 5

In an electrophoretic mobility shift assay, the labeled target fragment is mixed in vitro with purified regulatory protein and subjected to electrophoresis through a __________ polyacrylamide gel.

A) agarose
B) denaturing
C) nondenaturing
D) DNA
E) regulatory

Question 6

When __________ interacts with RNA polymerase, it increases the rate of transcription initiation of the lac operon.

A) cAMP receptor protein
B) LacI protein
C) lactose
D) allolactose
E) glucose

Question 7

All of the following typically occur in the presence of high glucose and high lactose concentrations EXCEPT:

A) Enzyme II glucose is unphosphorylated.
B) cAMP concentrations are low.
C) CRP levels in the cell are low.
D) Adenylate cyclase is inhibited.
E) Lactose is kept out of the cell.

Question 8

What occurs when an inducer is added to a medium containing an organism with a metabolic pathway controlled by a repressor?

A) The inducer combines with the repressor and activates the repressor
B) The inducer combines with the repressor and inactivates the repressor
C) The inducer combines with the substrate and blocks induction
D) The inducer combines with the substrate and activates induction
E) The inducer does not combine with but functions as a chaperone molecule for the enzyme-substrate complex

Question 9

Symmetry, in terms of DNA binding, usually involves a/an __________.

A) inverted repeat
B) major groove
C) chaperone
D) mRNA
E) quorum sensing

Question 10

A transmembrane sensor kinase protein senses an environmental condition outside __________ bacteria or in the periplasm of a/an __________ bacteria.

A) Gram-positive; Gram-negative
B) Gram-negative; Gram-positive
C) prokaryotic; eukaryotic
D) prokaryotic; archaean
E) Gram-positive; acid-fast

Question 11

A feature common to all control mechanisms is:

A) quorum sensing
B) phosphorylation cascades
C) ability to sense that something inside or around the cell has changed
D) housekeeping enzymes
E) increased or decreased gene expression

Question 12

Which form of control is the least reversible and most drastic?

A) alterations of DNA sequence
B) control of transcription
C) mRNA stability
D) translational control
E) posttranslational control

Question 13

Which of the following is used to precisely identify the DNA sequence to which a specific protein binds?

A) sequence analysis
B) gel shift assay
C) DNA footprinting
D) all of the above
E) none of the above

Question 14

Sets of genes in operons are coordinately regulated by which of the following?

A) protein repressors
B) activators
C) sigma factors
D) small RNAs
E) all of the above

Question 15

How many of the gene products of the lactose operon are required for the utilization of lactose to occur?

A) none
B) one
C) two
D) three
E) four

Question 16

Finding an inverted repeated sequence within 100-200 bases of a promoter suggests the presence of a __________ binding site.

A) DNA
B) regulatory
C) RNA
D) ribosome
E) corepressor

Question 17

If a gene is always expressed, it is:

A) constitutive
B) inducible
C) repressible
D) derepressible
E) promotable

Question 18

The transfer of a phosphate group from a phosphorylated sensor kinase to its cognate response regulator is referred to as:

A) chemophosphorylation
B) autophosphorylation
C) transphosphorylation
D) dephosphorylation
E) pyrophosphorylation

Question 19

__________ prevent transcription, whereas __________ stimulate transcription.

A) Activators; repressors
B) Inducers; corepressors
C) Corepressors; inducers
D) Regulators; repressors
E) Repressors; activators

Question 20

In some, but not all, instances, __________ molecules bind RNA transcripts and help or hinder degradation.

A) sRNA
B) rRNA
C) tRNA
D) mRNA
E) tsRNA

Question 21

Which of the following explains the regulatory activity of sRNA?

A) It codes for a sigma factor.
B) It prevents CRP interaction with RNA polymerase, thereby blocking its access to the promoter.
C) It synthesizes ppGpp.
D) It target mRNAs for degradation.
E) It creates an attenuator stem loop.

Question 22

DNA protected by a binding protein will leave a/an __________ where the binding protein comes in close proximity to DNA.

A) inverted repeat
B) fingerprint
C) promoter
D) footprint
E) repressor

Question 23

__________ RNAs bind to complementary sequences of target transcripts and stimulate or prevent translation.

A) Ribosomal
B) Transfer
C) Messenger
D) Antisense
E) Small

Question 24

Which of the following is NOT true of phase variation?

A) The orientation of the DNA sequence is inverted.
B) It may help the bacteria avoid the immune system.
C) It can result in a change in microbial appearance.
D) It only occurs in prokaryotes.
E) All are true.

Question 25

Which of the following is NOT true of sRNA genes?

A) They have a ribosomal binding site.
B) They occur between genes.
C) They share homology between related species.
D) They can act as antisense RNAs.
E) The gene product was Molecule of the Year in 2002.

Question 26

The class __________ DNA-binding motif is common to many DNA-binding proteins.

A) stem-and-loop
B) inverted-repeat
C) hairpin
D) helix-turn-helix
E) double-helix

Question 27

When the forespore is first produced, about how much of the chromosome is actually inside the forespore?

A) 10%
B) 20%
C) 30%
D) 40%
E) 50%

Question 28

Single-celled eukaryotic microbes generally have fewer introns than:

A) prokaryotes
B) Gram-negative bacteria
C) Gram-positive bacteria
D) multicellular eukaryotes
E) E. coli

Question 29

The stringent response relies on the production of:

A) pG
B) ppG
C) pppG
D) pGp
E) ppGpp

Question 30

The helix-turn-helix motif is able to fit into the __________ groove of a DNA molecule.

A) inverted-repeat
B) protein
C) RNA
D) minor
E) major

Question 31

The araBAD and araC genes are transcribed in the __________ direction with respect to each other.

A) same
B) opposite
C) forward
D) left
E) right

Question 32

Transcriptional attenuation is a common regulatory strategy used to control many operons that code for what?

A) amino acid degradation
B) amino acid biosynthesis
C) carbohydrate degradation
D) carbohydrate biosynthesis
E) none of the above

Question 33

The AraC-like regulators share homology with each other at which locations?

A) both their C-terminal end and their N-terminal end
B) neither their C-terminal end nor their N-terminal end
C) their C-terminal end only
D) their N-terminal end only
E) the center

Question 34

The stringent response involves all EXCEPT:

A) downregulation of rRNA synthesis
B) downregulation of tRNA synthesis
C) ATP
D) GTP
E) cAMP

Question 35

Some introns occur in archaea, a feature that archaea share with __________.

A) eukaryotes
B) prokaryotes
C) bacteria
D) operons
E) coliforms

Question 36

__________ genes always occur in intergenic regions.

A) tRNA
B) mRNA
C) sRNA
D) rRNA
E) tsRNA

Question 37

Some microbes use gene regulation to periodically change their appearance in a process called __________.

A) sporulation
B) attenuation
C) regulation
D) activation
E) phase variation

Question 38

Genes encoding known sRNA molecules always occur between genes encoding ORFS and exhibit how much homology between related species?

A) 10%
B) 20%
C) 40%
D) 60%
E) 80%

Question 39

Binding of tryptophan to the __________ makes a holorepressor.

A) aporepressor
B) corepressor
C) repressor
D) inducer
E) activator

Question 40

The little amount of sigma H that is made at 30°C is __________ by the DnaK/GrpE/DnaJ chaperones.

A) enhanced
B) activated
C) degraded
D) protected
E) folded

Question 41

If the newly synthesized DNA strand slips back relative to the template strand, one copy of the repeated unit is __________ the growing strand.

A) inserted in
B) deleted from
C) folded over
D) folded under
E) bound to

Question 42

What is an electrophoretic mobility shift assay? What is it used for and how is it performed?

Question 43

Explain the process of attenuation in regulating transcription of the tryptophan operon.

Question 44

How is repression of biosynthetic pathways different than repression of a catabolic pathway? Why does repression of these two types of pathways have to work differently?

Question 45

Compare and contrast prokaryotic activator sequences and eukaryotic enhancer sequences.

Question 46

A quorum-sensing gene system requires the accumulation of a secreted small molecule called a/an __________.

A) autoinducer
B) activator
C) repressor
D) inducer
E) corepressor

Question 47

When lambda becomes a prophage that integrates into the host chromosome, it expresses how many genes?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 48

The AraC regulator both activates and represses transcription of the genes involved in arabinose catabolism. How is this system more advantageous to a cell than a simpler repressor system like that used on the lac operon?

Question 49

Phase variation in Salmonella enterica involves:

A) gene inversion
B) chemotaxis
C) outer membrane proteins
D) sRNA
E) slipped-strand mispairing

Question 50

GlnB allows cells to balance glutamine synthetase __________ with its rate of __________.

A) amount; degradation
B) mRNA; translation
C) mRNA; transcription
D) synthesis; activity
E) activity; synthesis

Question 51

Glucose transport into the cell indirectly inhibits an enzyme closely associated with the phosphotransferase system. What is this enzyme and what is its role in the metabolism of lactose?

Question 52

What is diauxic growth and why does this occur?

Question 53

Depending on the lysogenic phage, the DNA is maintained by integrating into the host chromosome or persists in the cytoplasm as a harmless __________.

A) virion
B) plasmid
C) DNA fragment
D) bacteriophage
E) mRNA

Question 54

All the cell's expressed RNAs are collectively referred to as the cell's __________.

A) genome
B) transcriptome
C) proteome
D) holoenzyme
E) ORF

Question 55

Integrated circuits can:

A) send a virus down alternate lifestyle paths
B) couple the genetic and biochemical control of a metabolic pathway
C) time the events of a developmental cycle
D) all of the above
E) none of the above

Question 56

In general, the more copies of a gene there are, the more of that gene's __________ can be made.

A) sequence
B) activator
C) product
D) repressor
E) regulator

Question 57

Which molecule is used for hybridization to DNA bound on a DNA microchip?

A) DNA
B) RNA
C) mRNA
D) cDNA
E) any of the above

Question 58

How is DNA sequence analysis used to study DNA protein binding?

Question 59

Explain a way that organisms sense and respond to their environment.

Question 60

The stringent response downregulates rRNA synthesis. Does it similarly downregulate ribosomal protein synthesis?

Question 61

How does multiplicity of infection (MOI) control phage lambda's lytic versus lysogenic decision-making process?

Question 62

During the process of endospore formation, different sigma factors are active in the mother cell and forespore. How is this possible and why is it important?

Question 63

Quorum sensing plays a role in interspecies communications. Describe the relationship between green seaweed Enteromorpha and Vibrio anguillarum bacterial cells in biofilms and explain how E. coli was used to understand this interaction.

Question 64

Explain the process of bioluminescence in Vibrio fischeri. How is this an example of a mutualistic relationship?

Question 65

Briefly explain the two-dimensional gels electrophoresis. What is the procedure used to determine and why are both dimensions necessary?

Question 66

What does the gene inversion in Salmonella enterica accomplish with respect to its course of infection? Briefly describe how this mechanism works.

Question 67

Explain how small, untranslated RNAs (sRNAs) regulate iron uptake and iron storage.

Question 68

How is sigma H degradation controlled by temperature and why is this important to the cell?

Question 69

What happens when strand slippage occurs on the template or the newly synthesized DNA strand? How does Neisseria gonorrhoeae use slipped-strand mispairing to its advantage?

Question 70

Give examples of general and specialized eukaryotic transcription factors. To what do they compare in the prokaryotic system?