BMS 503 Final Exam (Exams 2 & 3)

The gene dnaE is an essential gene in E. coli that encodes the alpha subunit of DNA polymerase III. Where would you expect to find the dnaE gene in E. coli?
a. the chromosome
b. on a plasmid
c. on a transposable element
d. all of the above

a. the chromosome

Supercoiling is important for the DNA structure of the chromosome, because:
a. it holds together the antiparallel strands of the DNA in the double helix
b. it provides energy for transcription
c. it condenses the DNA so that it can fit inside the cell
d.

c. it condenses the DNA so that it can fit inside the cell

DNA replication, transcription, and translation all share the following three steps:
a. induction, repression, activation
b. separation, polymerization, condensation
c. start codon, tRNA, stop codon
d. initiation, elongation, termination

d. initiation, elongation, termination

The regulation of gene expression in response to fluctuations in cell-population density is called
a. signal transduction
b. quorum sensing
c. population dependent expression
d. phase variation

b. quorum sensing

DNA is ________ to DNA and __________ into mRNA.
a. transcribed, translated
b. translated, transcribed
c. replicated, transcribed
d. transcribed, replicated

c. replicated, transcribed

Transfer RNA (tRNA) molecules:
a. contain codons that bind to ribosomes during translation
b. function to transfer ribonucleotides to RNA polymerase during transcription
c. are only present in the nucleus or eukaryotes
d. function to transfer the correct

d. function to transfer the correct amino acids to the ribosome during translation

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Expression of the operon above leads to an mRNA (the blue squiggle) that encodes three proteins. This mRNA is described as being:
a. monocistronic
b. dicistronic
c. multicistronic
d. polycistronic

d. polycistronic

Cyclic AMP is synthesized from ATP by an enzyme called _____ and plays a role in _________.
a. adenylate cyclase, catabolite repression
b. adenylate cyclase, translational activation
c. cAMP receptor protein (CRP) synthase, catabolite repression
d. cAMP r

a. adenylate cyclase, catabolite repression

What is the role of PriA during bacterial chromosome replication:
a. binding and polymerization of PriA allows DNA strand separation at oriC initiating DNA replication
b. synthesis of the lagging strand of DNA during DNA replication
c. generating the RNA

c. generating the RNA primers necessary for DNA replication

True or False: DnaA binding to oriC causes DNA strand separation and allows for initiation of DNA replication.
a. true
b. false

a. true

During DNA replication of Okazaki fragments __________ removes RNA primers, ___________ synthesizes DNA to fill the gaps and _________ connects the DNA fragments.
a. RNAse H, DNA Polymerase III, and DNA Polymerase III
b. RNAse H, DNA Polymerase I, and DNA

c. RNAse H, DNA Polymerase I, DNA Ligase

Termination of DNA synthesis involves which of the following factors:
a. Tus and ter sites
b. Ribosome and the Shine Dalgarno Sequence
c. Sigma factor and the -35 sequence
d. DnaA and oriC

a. Tus and ter sites

Dr. Strummer experimentally changes the DNA sequence directly upstream of a translation codon of genX in E. coli to investigate the function of this region of DNA. Experiments reveal that after the change the same amount of genX mRNA is made from the oper

b. the DNA sequence likely functions as a ribosome-binding site

True or False: Rho factor is required for the termination of all transcription in a bacterial cell.
a. true
b. false

b. false

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Tube A- growth at top
Tube B- heavy growth at top, but some throughout whole tube
Tube C- growth at bottom
Tube D- growth throughout whole tube
Thioglycollate broth culture tubes of bacteria.
Which pattern of bacterial growth in the a

c. tube C

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the graph above is bacterial growth curve of a liquid culture. which section of the curve denotes exponential growth?
A
B
C
D

B

bacteria increase in mass during which stage of the cell cycle?
a. A period
b. B period
c. C period
d. D period

b. B period

the ___________ subunit of RNA polymerase is responsible for recognizing the promoter of a gene.
a. alpha
b. beta
c. omega
d. sigma

d. sigma

Dr. Strummer is growing a laboratory strain of E. coli in MacConkey broth. he inoculated the culture broth with 50 bacteria. after 4 hours of growth, Dr. Strummer uses a plate Colony Unit Assay and determines his culture now has 15,000 bacteria, what is t

b. 30 minutes

which of the following statements accurately describes the role of rRNA molecules in a cell?
a. rRNAs transfer the correct amino acids to the ribosome during translation
b. rRNAs transfer ribonucleotides to RNA polymerase during transcription
c. rRNAs are

c. rRNAs are a main component of the ribosome and catalyze the joining of amino acids in a growing peptide

Dr. Strummer is investigating the mechanism of action of a new antibiotic, Toppercillin. Staphylococcus aureus cells exposed to Toppercillin fail to crosslink their peptidoglycan cell wall. which factor important for cell growth and division is Toppercill

c. transpeptidase

the codon on the _______ matches with the anticodon on the ______ to direct the addition of the correct amino acid to the growing polypeptide chain.
a. mRNA, tRNA
b. tRNA, mRNA
c. DNA, mRNA
d. tRNA, rRNA

a. mRNA, tRNA

the template for RNA polymerase is _______, and the new RNA chain is _______ to the template.
a. an independent RNA segment, identical
b. an independent RNA segment, antiparallel
c. DNA, identical
d. DNA, complimentary

d. DNA, complimentary

Dr. Strummer experimentally changes the DNA sequence at the beginning of the lacI coding sequence in E. coli to investigate the function of this region of DNA. He changes the DNA code so that the mRNA codes for UAG instead of AUG. experiments reveal that

b. Dr. Strummer mutated the translational start codon of the mRNA to a stop codon

in response to an external signal the sensor kinase of a two-component signal transduction system:
a. phosphorylates (adds a phosphate to) itself and then phosphorylates a response regulator
b. phosphorylates itself and then interacts with the promoter of

a. phosphorylates (adds a phosphate to) itself and then phosphorylates a response regulator

Dr. Strummer is working with a laboratory strain of E.coli that has a mutation in the lacY gene and this does not produce functional lacY protein. which of the following statements about this strain is correct:
a. this strain will express the lactose oper

b. this strain is unable to import lactose into the cell

Dr. Strummer is investigating a new strain E. coli that is unable to maintain osmotic homeostasis in response to an increase in environmental salt concentrations. DNA sequencing of this new strain reveals a mutation in the envZ gene that results in a non-

a. it lacks the ability to sense the change in extracellular salt concentrations

Vibrio fischeri regulates the expression of Luciferase, an enzyme that makes it bioluminescent, by utilizing quorum sensing. during what stage of a growth curve of Vibrio fischeri, would you expect the see the strongest bioluminescence?
a. lag phase
b. ex

c. stationary phase

chromosome replication in bacteria does NOT require which of the following:
a. DNA polymerase I
b. DNA polymerase II
c. RNA polymerase
d. DnaA

c. RNA polymerase

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The growth curve below denotes an E. coli culture grown in media containing glucose and lactose. pick the section of the curve that best represents exponential (log) growth utilizing lactose.
A
B
C
D

C

phosphorylation of _______ regulates which direction of a flagellum rotates, thus controlling whether an organism runs or tumbles.
a. CheZ
b. CheB
c. FliC
d. CheY

d. CheY

genes that are organized by a common regulatory element are referred to as:
a. operons
b. regulons
c. introns
d. megatrons

a. operons

Dr. Strummer is investigating a new strain Vibrio cholera that is unablr to make high levels of cholera toxin. DNA sequencing of this new strain reveals a mutation in the toxT gene that results in a non-functional toxT protein. this strain is unable to pr

d. it lacks the direct, positive regulator of the ctAB genes

the time between inoculation of bacteria into liquid media and the beginning of growth is usually called the
a. lag phase
b. exponential phase
c. stationary phase
d. growth phase

a. lag phase

Dr. Strummer is growing a culture of Streptococcus pneumoniae in nutrient broth. he begins by inoculating the nutrient broth with 35 bacteria. he allows the bacteria to grow for 3 hours. the generation time for S. pneumoniae in nutrient broth is 60 minute

c. 280

Dr. Strummer is investigating a strain of E.coli that is unable to grow at temperatures above 37 degrees celcius. He observes that this strain of bacteria is UNABLE TO EXPRESS any of the genes that code for heat shock proteins that help E. coli deal with

d. the bacteria has a mutation in the sigma factor used for transcription of the heat shock genes

wild-type cells of E.coli can synthesize tryptophan, an essential amino acid. to do so, they need to express the five genes of the trpEDCBA operon (trpE, trpD, trpC, trpB, trpA) which encode enzymes that allow for the synthesis of tryptophan from chorisma

c. a negative regulator of the trpEDCBA operon

Previous studies have demonstrated that trpR binds DNA in the promoter region of the trpEDCBA operon. TrpR to binding the DNA is dependent on tryptophan. TrpR-tryptophan complex can bind the trpEDCBA operon promoter sequence, trpR alone cannot bind trpEDC

b. co-repressor

Bonus: Camplylobacteriosis is a common bacterial infection that can cause diarrhea, abdominal pain and fever in humans and animals. typically these infections are treatable with oral antibiotics, but a recent multi-state outbreak Campylobacteriosis has te

c. puppies sold at petland pet stores

Kanamycin is a:
a. bacteriostatic antibiotic that inhibits translation
b. bactericidal antibiotic that inhibits translation
c. bactericidal antibiotic that inhibits transcription
d. bacteriostatic antibiotic that inhibits DNA replication

a. bacteriostatic antibiotic that inhibits translation

Dr. Strummer is working with Streptococcus pneumoniae HACh00, a bacteria that has a mutation in the pilA gene. the mutation has changed the 5th codon in pilA from the codon for alanine to the codon for glycine. this mutation is an example of:
a. silent mu

b. missense mutation

using transformation and generalized recombination, Dr. Strummer changes the mutant 5th codon in the pilA gene of Streptococcus pneumoniae HACh00 from the codon for glycine back to the wild type codon for alanine. This mutation is an example of:
a. second

d. same site reversion

[experiment: PArt 1: Dr. Strummer is working with Streptococcus pneumoniae HACh00, a bacteria that has a mutation in the pilA gene. the mutation has changed the 5th codon in pilA from the codon for alanine to the codon for glycine. this mutation is an exa

a. true

which of the following is a mechanism of antibiotic resistance?
a. the bacteria is impermeable to the antibiotic
b. drug inactivation by an enzyme in the bacteria
c. the bacteria pumps the drug out of its cytoplasm using a protein efflux pump
d. all of th

d. all of the above

the Ames Test uses histidine _______ to determine the ______ of a chemical compound.
a. auxotrophy, mutagenicity
b. auxotrophy, toxicity
c. prototoxy, toxicity
d. isotrophy, mutagenicity

a. auxotrophy, mutagenicity

true or false: Generalized/homologous recombination can be utilized by cells to fix damaged DNA or stuck DNA replication forks.
a. true
b. false

a. true

Dr. Strummer would like to give E.coli MG1655 the ability to grow in the presence of ampicillin. he mixed E.coli MG1655 bacteria with E.coliDH5 bacteria that carry an F' plasmid containing an ampicillin resistance gene, ampR. he then plates the mixture on

c. conjugation

a virulent bacteriophage:
a. replicates in its host and then lyses the host cell to release new virions
b. inserts its genome into the host chromosome
c. can do either A or B depending on the nutrition of the host cell
d. none of the above

a. replicates in its host and then lyses the host cell to release new virions

viral envelopes are composed of ______ that are synthesized by ___________.
a. phosphlipids, viral proteins
b. phospholipids, host proteins
c. proteins, viral ribosomes
d. proteins, host ribosomes

b. phospholipids, host proteins

the late genes of the T4 genome encode:
a. sigma factors and an RNA polymerase
b. nucleases and replication proteins
c. RNA polymerase modifying proteins
d. capsid, assembly and release proteins

d. capsid, assembly and release proteins

Lambda is an example of a _________________ bacteriophage, while T4 is an example of a ______________ bacteriophage.
a. temperate, virulent
b. lysogenic, lytic
c. virulent, temperate
d. lytic, specialized

a. temperate, virulent

lambda phage infects a bacteria growing in nutritionally rich growth media. which of the following statements is TRUE.
a. lambda phage will enter the lysogenic cycle due to high levels of CII, which is a direct positive regulator of CI repressor expressio

c. lambda phage will enter the lytic cycle due to low levels of CII, which is a direct positive regulator of CI repressor expression

how do bacteriophage influence bacterial evolution?
a. bacteriophage cause cleavage and rearrangement of bacterial genomes, thus accelerating bacterial evolution
b. bacteriophage lyse mutated bacterial cells, thus preventing them from replicating and pass

c. bacteriophage transfer genetic information between bacterial cells through transduction, thus increasing the genetic diversity of bacterial populations

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the micrograph above depicts Tobacco Mosaic Virus virions. tobacco mosaic virus has _________ capsid symmetry.
a. helical
b. icosahedral
c. coiled
d. rod-shaped

a. helical

which of the following viral activities is not observed during the latent period of the viral life cycle?
a. synthesis of viral nucleic acid
b. translation of viral proteins
c. assembly of virions (complete viral particles)
d. release of virions from the

d. release of virions from the host cell

true or false: After uncoating, a single-strand, positive sense DNA viral genome can be directly transcribed by host cell RNA polymerases.
a. true
b. false

a. true

release of an animal virus from a host cell occurs through:
a. lysis of the host cell
b. budding and shedding of virus from the host cell
c. both A & B depending on the specific virus
d. none of the above

c. both A & B depending on the specific virus

A lambda prophage/lysogen will become lytic under which of the following conditions:
a. the infected bacterium finds itself in rich growth media and can undergo rapid growth
b. the infected bacterium finds itself in poor growth media and can undergo limit

c. the infected bacterium undergoes DNA damage

the uptake of DNA released from a cell is ________, while transfer of DNA with cell-to-cell contact is referred to as ________.
a. transformation, conjugation
b. transduction, conjugation
c. conjugation, transformation
d. transformation, transduction

a. transformation, conjugation

as oxygen appeared in the atmosphere, ____________ also accumulated, which formed a protective barrier that protects the Earth from __________________.
a. ozone, UV radiation
b. elemental sulfur, volcanism
c. ferrous iron, oxygen free radicals
d. sulfate,

a. ozone, UV radiation

for the average human, Rottenicin has a therapeutic dose of 5mg and a toxic dose of 500mg. What is chemotherapeutic index of Rottenicin?
a. 0.01
b. 2500
c. 10
d. 100

d. 100

the size of a viral particle is largely governed by the size and packaging of the viral:
a. envelope
b. enzyme
c. prophage
d. genome

d. genome

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the micrograph above depicts T4 bacteriophage. T4 bacteriophage has a capsid with __________ symmetry.
a. helical
b. complex
c. icosahedral
d. droid

b. complex

the most widely used molecules in sequence-based evolutionary analysis are ________ genes.
a. ATPase
b. electron transport
c. SSU rRNA
d. tRNA

c. SSU rRNA

based on the phylogenetic tree below, which of the following statements is FALSE:
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a. species E is more closely related to species A than to species D
b. species D is more closely related to species C than to species E
c. species F is mo

b. species D is more closely related to species C than to species E

consider a mutation in which the change is UAC to UAU. both codons specify the amino acid tyrosine. which type mutation is this?
a. silent mutation
b. nonsense mutation
c. missense mutation
d. frameshift mutation

a. silent mutation

a mutant that has a nutritional requirement for an amino acid (the amino acid needs to be supplied in the media) for growth is an example of a(n):
a. autotroph
b. auxotroph
c. heterotroph
d. organotroph

b. auxotroph

treatment of E.coli MG1655 with Acridine Orange, an intercalating agent, leads to a two DNA base pair insertion mutation at codon 10 of lacZ. which type of mutation is this?
a. silent mutation
b. nonsense mutation
c. missense mutation
d. frameshift mutati

d. frameshift mutation

true or false: the earliest nucleic acid was probably a simple DNA molecule
a. true
b. false

b. false

the mismatch repair system is an example of a/an ____________.
a. error-prone repair system
b. error-proof repair system
c. low-fidelity repair system
d. frameshift repair system

b. error-proof repair system

two eukaryotic organelles that are hypothesized to be the result of endosymbiosis are the ___________ and the ___________.
a. nucleus, golgi apparatus
b. mitochondrion, chloroplast
c. endoplasmic reiticulum, golgi apparatus
d. hydrogeosome, chloroplast

b. mitochondrion, chloroplast

Ciprofloxacin is an example of a ____________ antimicrobial that inhibits ___________.
a. bacteristatic, transcription
b. bactericidal, cell wall biosynthesis
c. bacteriostatic, translation
d. bactericidal, DNA replication

d. bactericidal, DNA replication

true or false: antibiotics are natural products produced and secreted by microorganisms.
a. true
b. false

a. true

ERROR-PRONE repair mechanisms are _________ fidelity and utilize ____________ to synthesize new DNA and ______________ ligate new repaired DNA to the chromosome.
a. low, DNA polymerase V, DNA ligase
b. high, DNA polymerase III, DNA ligase
c. high, DNA pol

a. low, DNA polymerase V, DNA ligase

RecA protein is involved in all of the following processes EXCEPT:
a. SOS DNA damage repair
b. Lambda prophage activation
c. generalized recombination
d. site-specific recombination

d. site-specific recombination

true or false: the result of an Hfr conjugation typically results in a recipient bacterium that is F+ and can transfer plasmid to new recipient bacteria.
a. true
b. false

b. false

to be transferred via conjugation, the F (fertility) plasmid must contain a set of genes that encode for the _______ proteins and a/an __________.
a. transduction, oirR
b. injection, oriC
c. transfer, oriT
d. transformation, oriQ

c. transfer, oriT

viruses and bacteria have a frequency of mutation that is ________ the frequency of mutation in muticellular eukaryotes.
a. lower than
b. higher than
c. about the same as
d. none of the above. mutations are lethal in multicellular eukaryotes

b. higher than

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Dr. Strummer is testing the effect of two new antibiotics on a culture of E.coli. using the curve above, which antibiotics would you describe as bactericidal?
a. Rottenicin
b. Viciousillin
c. Rottenicin and Viciosillin
d. neither Rotte

b. Viciousillin

Dr. Strummer is studying ampicillin resistant (AmpR), non-pathogenic bacterial species, Streptococcus safeus. he hypothesizes that he can make this organism pathogenic by mixing it with a pathogenic species of bacteria. in experiment 1, Dr. Strummer infec

c. conjugation

Dr. Strummer is studying ampicillin resistant (AmpR), non-pathogenic bacterial species, Streptococcus safeus. he hypothesizes that he can make this organism pathogenic by mixing it with a pathogenic species of bacteria. in experiment 1, Dr. Strummer infec

a. to select for S. safeus in his bacterial mixture and assure he is not infecting mice with S. pneumoniae.

the principle that an antibiotic should harm the pathogen but not the host is referred to as:
a. drug specificity
b. antimicrobial selectivity
c. selective toxicity
d. none of the above

c. selective toxicity

BONUS: Mann PAcking, a California vegetable supplier for Whole Foods, Trader Joes, and Walmart was recently forced to recall multiple vegetables due to contamination with:
a. Escherichia coli
b. Salmonella enterica Typhi
c. Norovirus
d. Listeria monocytog

d. Listeria monocytogenes