Deck 13: Bacterial Genetics

Question 1

If an organism is isolated that has no nuclear membraneand the DNA is condensed into a body in the cytoplasm this organims would most likely be classified as a

A)Prokaryote
B)Eukaryote
C)Archaea
D)could either be a Eukaryote or Prokaryote

Answer 1

Prokaryote

Question 2

Match each item in the left column with the single most appropriate item in the right column.Each number should be used only once.

Answer 2

a 4; b 1; c 6; d 7; e 5; f 3; g 2

Question 3

If the Tn10 transposon is used to mutagenize a bacterium for the purpose of creating a mutant in the His operon what would be the most appropriate selection media?

A)Rich media that contains all of the amino acids supplemented with tetracycline.
B)Minimal media just supplemented with His
C)Minimal media supplemented with tetracycline and His
D)Minimal media supplemented with tetracycline alone.

Answer 3

Minimal media supplemented with tetracycline and His

Question 4

Viruses are isolated from wild typeE.coli cells that have been infected with wild type $\lambda$ .These viruses are used to infect a gal^- strain of E.coli. A few bacterial colonies that grow on minimal galactose are obtained while no bacteria are obtained in cells that are not infected.What has happened?

A)A $\lambda$ gal⁺ phage was generated
B)Reversion mutations have occured.
C)The bacteria underwent conjugation with a gal⁺ strain
D)The bacgteria underwent transformation with a wild type

Question 5

Match each item in the left column with the single most appropriate item in the right column.Each number should be used only once.

Question 6

The episome in an Hfr strain is inserted near the trp (tryptophan) locus.This Hfr strain is incubated with an F^-trp^- strain.We isolate a trp⁺ strain that can readily donate the trp⁺ phenotype to other F^- trp⁺ strains.No other traits are transferred.What has happened?

A)An F⁺ trp plasmid has been generated
B)Typical Hfr mating
C)Transduction occurs
D)Transformation occurs

Question 7

There are "promiscuous plasmids," plasmids that can replicate in several different species of bacteria.Frequently these plasmids have transposons carrying antibiotic resistance.In a hospital that has an outbreak of a variety of bacteria carrying resistance to streptomycin, gentamicin, and penicillin how what is the best way to determine that this resistance was due to a shared plasmid?

A)Demonstrate that all the resistant bacteria have a plasmid and that these plasmids have an identical (or nearly identical) sequence..
B)Isolate plasmids from all resistant bacterial species and demonstrate that sensitive cells from these same species become resistant when this plasmid is transformed..Confirm that these are the same plasmids by sequencing.
C)Sequence the genomes of the resistant sspecies and demonstrate mutations in the same homologous genes..
D)Isolate any plasmids from one resitant species and transform a sensitive strain of the same bacterium to see if resistance occured in the transformants.

Question 8

A plasmid that contains an open reading frame for the penecillin resistance gene flanked at the 5' end with sequences from the LacZ gene and at the 3' end with different sequences from the LacZ open reading frame.Bacgteria are plated on media that contains penecillin.What is the conclusion regarding the bacteria that grow on the plate?

A)The plasmid is inhibiting LacZ production
B)The genome carries a mutation in the LacZ gene.
C)No inference can be made concerning the state of the genomic LacZ gene.
D)The bacteria should be able to produce beta-galactosidase

Question 9

Which of the following is an infection in newborn infants when born to mother with gonorrhea?

A)pneumonia
B)brain lesions
C)eye infection
D)heart disease
E)tendon inflammation

Question 10

What is a typical characterisitc of bacterial chromosomes?

A)5% of the sequences encodes proteins
B)It has telomeres
C)It is linear.
D)On average a gene occurs once in every 1000bp

Question 11

If an Hfr cell is used for mating what is the last gene that could possibly be transfered from the host chromosome?

A)A gene that is at the site of integration and on the same side as where transfer starts..
B)A gene that is at 45 minutes from the site of integration.
C)A gene that is at the site of integration of the episome but on the opposite side from where transfer starts
D)A gene that is at 30 minutes from the site of integration

Question 12

Penecillin stops bacterial cell wall formation by

A)inhibition of a transpeptidase.
B)inhibiting synthesis of NAM.
C)inhibiting synthesis of NAG
D)inhibiting transport of NAG and NAM past the permeale membrane.

Question 13

A bacterium is found that is resistant to the antibiotic gentamicin.The bacterium was isolated in a hospital where patients were routinely given gentamicin for a variety of infections.What was the pressure that selected for this resistant population?

A)Presence of gentamicin in the environment.
B)High mutation rate for the bacterium.
C)Growth situation for the bacterium.
D)Patients not receiving antibiotic provided source of bacteria.

Question 14

We isolate nine different mutants unable to make histidine.They map in different locations and by genetic means we can show there are nine different genes in the pathway.How many enzymes can we anticipate finding in this pathway?

A)1
B)3
C)6
D)9
E)12

Question 15

What would happen if a transposon were to integrate into the origin of the bacteria genome?

A)Transposon would be replicated like the genome.
B)Transposon would "jump" to another location.
C)Transposon would inactivate the origin, no DNA replication possible.
D)Transposon would express its genes constitutively.

Question 16

Which of the following is a bacterial disease common among sexually active individuals?

A)gonorrhea
B)Haemophilus infections
C)pneumonia
D)pancreatitis
E)jaundice

Question 17

What characterisitcs make bacteria like E.coli attractive as model organisms?

A)Short generation time, realtively simple genome, easily mutagenized, haploid, gene control mechanisms identical to eukaryotes.
B)Short generation time, realtively simple genome, easily mutagenized, haploid.
C)Short generation time, realtively complex genome, easily mutagenized, haploid.
D)Short generation time, realtively simple genome, easily mutagenized, diploid.

Question 18

Which technique would most likely be used for mapping genes that are separated by 2 x 10⁷ base pairs?

A)Specialized transduction
B)Generalized transduction
C)Conjugation
D)Transformation

Question 19

Two F⁺ E coli strains are co-cultured in the same flask.One is Str^r Thr⁺ and the other is Gen^r Thr^-.The culture is then plated on minimal media that is supplemented with gentamycin only and a few colonies grow.What sort of genetic exchange is most likely occurring?

A)Transformation
B)Conjugation
C)Transduction
D)Electroporation

Question 20

A strain of E.coli is trp? his? lac?.Which medium would this bacterium grow on?

A)lactose + histidine + tryptophan
B)glucose + histidine + tryptophan
C)maltose + histidine + tryptophan
D)minimal glucose, no histidine, no tryptophan
E)glucose + histidine + tryptophan and maltose + histidine + tryptophan

Question 21

Which gene would you predict would be part of the core genome and not the pangenome?

A)Gene involved in glucose utilizaation
B)Antibiotic resistance gene
C)Metal resistance gene.
D)Transposase.

Question 22

What is a property of a pathogenic bacterium?

A)It may produce a protein that interferes with basic cellular functions.
B)There may not be a non-pathogenic strain of the same species.
C)It probably conducts photosynthesis.
D)It probably fixes nitrogen.

Question 23

Metagenomics may be useful because

A)it could be used to detect diseases..
B)It will allow for the sequencing of entire bacterial species genomes.
C)Metagenomes do not change rapidly.
D)Metagenomes are not responsive to environmental canges.

Question 24

What is a difference between a Tn and IS element?

A)Tn elements can carry antibiotic resistance genes.
B)IS elements carry a transposase gene.
C)Tn elements integrate into plasmids and genomes.
D)IS elements integrate into plasmids and genomes.

Question 25

What would you anticipate would be true about the metabolism of a bacterial species isolated from water samples one at the surface and another from a hot vent on the ocean floor?

A)The species from the water surface would most likely be able to conduct photosynthesis.
B)The species from the hot vent would most likely be able to conduct photosynthesis.
C)The species from the hot vent would most likely be able to fix nitrogen
D)The species from the hot vent would most likely be able to degrade oil.

Question 26

Horizontal gene transfer can

A)accelerate evolution of a species
B)inihbit evolution of a species.
C)has no role in evolution.
D)only has a role in evolution if the transfer is to a different species.

Question 27

A strain of N.gonorrhoeae is isolated that does not have a plasmid.If a lysate is made from the bacterium it cannot degrade penecillin in an in vitro assay.When a cuture of this strain is grown in a solution that contains radioactive penicillin the amount of penecilllin found within cells is less than the amount found in a non-resistant strain.Sequence of the porin gene from the resitant strain does not have any mutations.What is the most likely mechanism of resistnace in this strain?

A)MtR mutation that results in inactivation or inhiition of MtR activity.
B)penA nonsense mutation.
C)penA missense mutation.
D)Genome carries pen^r gene.