Deck 9: Bacterial Genetic Analysis

Question 1

The process of molecular cloning was mainly brought about through the discovery of these.

A)bacteriophages
B)transposons
C)transformations
D)restriction enzymes
E)conjugation events

Answer 1

D

Question 2

You are searching for a mutant strain of E.coli with no heat shock proteins.What approach is most likely to be successful?

A)positive phenotypic selection
B)DNA sequencing of cells within a population
C)Environmental searching for a new population
D)Toothpick pick-and-patching
E)None is likely to succeed

Answer 2

D

Question 3

You are searching for a mutant strain of Sinorhizobium melitoti which is antibiotic sensitive.What approach is most likely to be successful?

A)positive phenotypic selection
B)DNA sequencing of cells within a population
C)Environmental searching for a new population
D)Replica plating
E)None is likely to succeed

Answer 3

D

Question 4

Escherichia coli strain K12 is considered a wild-type strain and does not have any nutritional vitamin requirements.What term applies to this strain?

A)An autotroph.
B)An auxotroph.
C)A phototroph.
D)A prototroph.
E)A lithotroph.

Question 5

You are searching for a mutant strain of E.coli which is antibiotic resistant.What approach is most likely to be successful?

A)positive phenotypic selection
B)DNA sequencing of cells within a population
C)Environmental searching for a new population
D)Toothpick pick-and-patching
E)None is likely to succeed

Question 6

What is an organism's complete collection of alleles called?

A)wild-type
B)prototype
C)phenotype
D)genotype
E)histotype

Question 7

You are searching for a mutant strain of E.coli with superior heat shock proteins.What approach is most likely to be successful?

A)positive phenotypic selection
B)DNA sequencing of cells within a population
C)Environmental searching for a new population
D)Toothpick pick-and-patching
E)None is likely to succeed

Question 8

You insert a gene for tetracycline resistance into one plasmid and a gene for ampicillin resistance into another plasmid.You successfully introduce both plasmids into a sample of E.coli cells,but fail to grow any of them in culture medium with both antibiotics present in it.What could best explain the problem?

A)Random mutation has inactivated the antibiotic resistance genes
B)Plasmid incompatibility will not allow both plasmids to persist
C)E)coli cannot maintain two plasmids
D)The plasmid(s)have integrated into the bacterial chromosome
E)A phage has neutralized one of the plasmids

Question 9

A bacterium which cannot synthesize all organic molecules needed for its growth is known as a/an:

A)prototroph
B)autotroph
C)organotroph
D)heterotroph
E)auxotroph

Question 10

You mix Met⁺ Pro⁻ Lys⁻,Met⁻,Pro⁻ Lys⁺ and Met⁻ Pro⁺ Lys⁻ auxotrophic strains of E.coli.After incubation time has passed,you place 10²⁰ cells per plate on agar to detect potential prototrophic colonies.How many plates need to be screened if gene transfer takes place only through random mutation?

A)approximately 10
B)approximately 1000
C)approximately 100,000
D)none is a correct estimate
E)only one plate would be necessary

Question 11

What is the "sexual transfer" of genes in bacteria called?

A)transformation
B)transduction
C)transfection
D)conjugation
E)coupling

Question 12

You are searching for a mutant strain of Serratia marcescens which produces no pigment.What approach is most likely to be successful?

A)positive phenotypic selection
B)DNA sequencing of cells within a population
C)Environmental searching for a new population
D)Replica plating
E)None is likely to succeed

Question 13

Suppose a mutant strain of Escherichia coli K12 contains a mutation in the trpE gene and is no longer able to make tryptophan.What is this mutant called?

A)An auxotroph.
B)A prototroph.
C)An autotroph.
D)A phenotroph.
E)A lithotroph.

Question 14

You insert a gene for tetracycline resistance into one plasmid and a gene for ampicillin resistance into another plasmid of the same incompatability group.You successfully introduce both plasmids into a sample of E.coli cells,and surprisingly succeed in obtaining growth in culture medium with both antibiotics present in it.What likely happened?

A)Random mutation has activated the antibiotic resistance genes
B)Plasmid incompatibility will not allow both plasmids to persist
C)E)coli cannot maintain two plasmids so they have integrated
D)One or more plasmid(s)have integrated into the bacterial chromosome
E)A phage has neutralized one of the plasmids

Question 15

You are searching for a Staphylococcus aureus mutant which needs lysine in the culture medium in order to grow (Lysine auxotroph).Which medium will assist your initial search?

A)Culture medium with lysine added
B)Culture medium with no lysine in it
C)Culture medium with lysine and penicillin added
D)Culture medium with no lysine in it and penicillin added
E)None are suitable

Question 16

Under what conditions will two different plasmids be incompatible?

A)If they contain some identical genes.
B)If they contain genes from different organisms.
C)If they use similar methods of replication initiation.
D)If they use different DNA polymerases.
E)If they do not contain at least one similar gene.

Question 17

Bacterial mutants have been very useful for studying and understanding:

A)biosynthetic pathways.
B)capsule production.
C)antibiotic resistance.
D)carbon metabolism.
E)all of these choices.

Question 18

You mix Met⁺ Pro⁻ Lys⁺,and Met⁻ Pro⁺ Lys⁺ auxotrophic strains of E.coli.After incubation time has passed,you place 10¹⁰ cells per plate on agar to detect potential prototrophic colonies.How many plates need to be screened if gene transfer takes place only through random mutation?

A)approximately 10
B)approximately 1000
C)approximately 100,000
D)none is a correct estimate
E)only one plate would be necessary

Question 19

Assuming mutation frequency to be around 10⁻⁶,at what frequency will quadruple mutant auxotrophs revert to prototrophy?

A)4 x 10-⁶
B)12 x 10-⁶
C)24 x 10-¹²
D)1 x 10-²⁴
E)None is a correct choice

Question 20

Compared to the eukaryal genome,the bacterial genome:

A)is more complex.
B)contains genes that are usually present in only one copy.
C)contains only a small percent of DNA that encodes for functional proteins.
D)is diploid in number.
E)is difficult to manipulate.

Question 21

A vector with a genome consisting of the cos fragments of phage lambda flanking exogenous DNA would be known as a:

A)plasmid vector
B)phage vector
C)cosmid vector
D)lysogen
E)lytic vector

Question 22

What sized fragments will be generated by cutting DNA with a four base pair-recognition restriction endonuclease if we assume equal A-T and C-G richness within the DNA?

A)roughly 250 bp
B)roughly 500 bp
C)roughly 100 bp
D)roughly 1,000 bp
E)roughly 5,000 bp

Question 23

Term for a plasmid cloning vector that is able to replicate in different genera of bacteria.

A)fertility plasmid
B)resistance plasmid
C)shuttle vector
D)transfection vector
E)cosmid vector

Question 24

What sized fragments will be generated by cutting DNA with a six base pair-recognition restriction endonuclease if we assume equal A-T and C-G richness within the DNA?

A)roughly 250 bp
B)roughly 20,000 bp
C)roughly 10,000 bp
D)roughly 1,000 bp
E)roughly 5,000 bp

Question 25

The first DNA cloning experiment required ALL of the following EXCEPT:

A)DNA ligase.
B)DNA polymerase.
C)restriction enzymes.
D)plasmid vector with antibiotic resistance gene.
E)competent cells.

Question 26

Early plasmid vectors used for cloning DNA contained:

A)a single restriction enzyme site.
B)unique restriction enzyme sites for several restriction enzymes.
C)multiple restriction enzymes sites for several restriction enzymes.
D)antibiotic resistance genes but no restriction enzyme sites.
E)multiple restriction sites for a unique restriction enzyme.

Question 27

You are attempting to find a restriction enzyme that will allow a 30,000 base pair gene fragment to be removed intact from a length of chromosomal DNA.Which enzyme will work best for you?

A)a four base pair cutter
B)a six base pair cutter
C)an eight base pair cutter
D)all will work equally well
E)none has a chance of working

Question 28

Term for cells that can naturally take up extracellular DNA.

A)porous
B)competent
C)conjugant
D)susceptible
E)primed

Question 29

Term for the uptake of extracellular DNA into a bacterial cell and incorporation into its genome.

A)transduction
B)conjugation
C)transformation
D)reversion
E)transfection

Question 30

The ________ protein is important in the process of recombination.

A)RecZ
B)RecA
C)TpnB
D)TpnC
E)TpnZ

Question 31

Which term applies to the transfer of genes from mother to daughter cell?

A)vertical gene transfer
B)lateral gene transfer
C)horizontal gene transfer
D)meiosis
E)transduction

Question 32

You are attempting to find a restriction enzyme that will allow a 2000 base pair gene fragment to be removed intact from a length of chromosomal DNA.Which enzyme will work best for you?

A)a four base pair cutter
B)a six base pair cutter
C)an eight base pair cutter
D)all will work equally well
E)none has a chance of working

Question 33

Which restriction endonuclease do you predict to generate DNA fragments which are most difficult to join with DNA ligase?

A)Eco RI
B)Bam HI
C)Hind III
D)Sma I
E)All would be equally efficient

Question 34

The enzyme ___________ hydrolyzes the chromogenic substrate X-gal.

A)α-amylase
B)β-lactamase
C)xylanase
D)β-galactosidase
E)glucuronidase

Question 35

Bacteriophages vary in their ability to infect different strains of bacteria.This is because some bacteria contain _________ __________ that cut the phage DNA after it enters the cell.

A)general nucleases
B)DNA helicases
C)DNA gyrases
D)restriction endonucleases
E)DNA topoisomerases

Question 36

Which of these is an example of a reporter gene that is used to study gene regulation in bacteria?

A)trpE
B)recA
C)lacZ
D)glyA
E)hisB

Question 37

Suppose a microbe has died and lysed,exposing its DNA to the environment.Some of this DNA was taken up by another unrelated microbe and incorporated into its genome.This is an example of which process?

A)transduction
B)vertical gene transfer
C)conjugation
D)horizontal gene transfer
E)endocytosis

Question 38

You are attempting to find a restriction enzyme that will allow a 200 base pair gene fragment to be removed intact from a length of chromosomal DNA.Which enzyme will work best for you?

A)a four base pair cutter
B)a six base pair cutter
C)an eight base pair cutter
D)all will work equally well
E)none has a chance of working

Question 39

What sized fragments will be generated by cutting DNA with an eight base pair-recognition restriction endonuclease if we assume equal A-T and C-G richness within the DNA?

A)roughly 25,000 bp
B)roughly 70,000bp
C)roughly 100,000 bp
D)roughly 1,000 bp
E)roughly 5,000 bp

Question 40

Which of the following processes would still occur in a RecA mutant?

A)conjugation
B)transformation
C)transduction
D)both conjugation and transformation
E)both transformation and transduction

Question 41

Term for the direct transfer of DNA from a living donor bacterium to a recipient bacterium.

A)transduction
B)transformation
C)transfection
D)conjugation
E)electroporation

Question 42

Which of these events is capable of generating a single,stable DNA molecule? (Select all that apply)

A)Single crossover between two linear DNA chromosomes
B)Single crossover between two circular DNA chromosomes
C)Double crossovers between circular chromosomes
D)Double crossovers between circular and linear chromosomes
E)None generates a single,stable DNA molecule

Question 43

Which of these proteins is considered to possess endonuclease activity? (Select all that apply)

A)RecA
B)RecBDC
C)DNA ligase
D)transposase
E)RNA ligase

Question 44

The CRITICAL gene when constructing suicide plasmids is:

A)sacB
B)lacZ
C)tetracycline resistance gene
D)ampicillin resistance gene
E)kanamycin resistance gene

Question 45

Suppose a strain of Escherichia coli is identified as an Hfr strain.In a conjugational experiment between the donor Hfr strain and a recipient E.coli strain that is F⁻,what would you expect to result?

A)The recipient to become F⁺.
B)The recipient to become an Hfr strain.
C)The recipient to remain F⁻.
D)The donor to become F⁻.
E)The donor to transfer the entire F-plasmid.

Question 46

What possible disadvantage might electroporation possess compared with the transformation achievable by species such as Bacillus?

A)Smaller DNA fragments are transferred
B)Double-stranded DNA,not single-stranded,is transferred
C)There is a loss of cells due to the voltage being applied
D)Antibiotic resistance selection processes cannot be employed
E)None is a correct choice

Question 47

The sucrose resistance phenotype,employed to distinguish single and double crossover events when non-homologous recombination is taking place,would not be detectible if a recipient cell were:

A)unable to hydrolyse sucrose
B)unable to hydrolyse lactose
C)unable to hydrolyse fructose
D)unable to polymerize fructose
E)unable to polymerize sucrose

Question 48

You mix Met⁺ Pro- and Met⁻ Pro⁺ auxotrophic strains of E.coli.If you incubate for one hour before plating to detect prototrophs,no colonies are seen,but if the incubation time is increased to three hours,prototrophic colonies form.What possible explanations could there be for this observation? (Select all that are plausible)

A)gene transfer cannot take place in such a short time
B)E)coli cannot replicate in one hour
C)Cells cannot take up DNA in one hour
D)Mutation cannot take place within one hour
E)All answers are equally likely

Question 49

Which of these enzymes is not required for homologos recombination to occur?

A)RecA
B)RecB
C)DNA ligase
D)RecD
E)DNA polymerase

Question 50

The original map of the Escherichia coli chromosome was constructed using which process?

A)conjugation
B)transformation
C)transduction
D)both conjugation and transformation
E)both conjugation and transduction

Question 51

Virulence plasmids from Bacillus anthracis possess transerability features comparable to those found in:

A)F plasmid
B)pSC101
C)pBR322
D)pSC105
E)none of these plasmids

Question 52

Genetic elements that are able to "jump" around on the chromosome.

A)chromatin
B)transposons
C)conjugants
D)resolvase
E)transductants

Question 53

Which of these recombination events can successfully insert a gene containg fragment through non-homologous recombination? (Select all that apply)

A)Double crossover between two circular molecules
B)Single crossover between two circular molecules
C)Double crossover between circular and linear molecules
D)Transposon activity
E)Transformation

Question 54

If the genes that distinguish Bacillus anthracis,B.cereus and B.thuringiensis from one another are all plasmid-encoded,it might be more correct to consider them as:

A)Strains of a single species
B)Genera of a single family
C)Species of a single genus
D)Genera of a single species
E)Species of a single family

Question 55

What is the difference between an Hfr strain and an F-prime strain of Escherichia coli?

A)The F-prime strain is not able to convert the recipient strain to F⁺.
B)The F-prime strain is able to transfer any gene on the chromosome to the recipient cell.
C)The F-prime strain has an F⁻ phenotype.
D)The Hfr strain is able to transfer more E.coli genes to the recipient than the F-prime strain.
E)The Hfr strain is unable to mate with an F⁻ strain.

Question 56

Which of these bacteria will likely take up double stranded DNA during transformation?

A)Bacillus subtilis
B)Escherichia coli
C)Streptococcus species
D)Neisseria meningitidis
E)Haemophilus influenzae

Question 57

You are searching for a Staphylococcus aureus mutant which needs lysine in the culture medium in order to grow (Lysine auxotroph).Which media will be necessary your search? (Select all that apply)

A)Culture medium with lysine added
B)Culture medium with no lysine in it
C)Culture medium with lysine and penicillin added
D)Culture medium with no lysine in it and penicillin added
E)None are suitable

Question 58

Term for the transfer of donor DNA to a recipient bacterium via a bacteriophage.

A)transduction
B)transfection
C)transformation
D)conjugation
E)lytic infection

Question 59

To detect insertional deactivation mutagenesis,biologists may employ: (Select all that apply)

A)sacB
B)lacZ
C)antibiotic resistance genes
D)restriction endonuclease
E)electroporation

Question 60

What types of cell do you theoretically expect might be transformable via electroporation but not naturally occurring transformation?

A)Bacillus
B)Streptococcus
C)Plant cells
D)Fungal cells
E)Escherichia

Question 61

A mutation in which genes could render Haemophilus incapable of transformation? (Select all that apply)

A)RecA
B)DNA translocase
C)Single strand exonuclease
D)Single strand endonuclease
E)DNA polymerase

Question 62

In order for a plasmid to replicate once it enters a cell,it must contain an ______ of replication that is recognized by the cell.

Question 63

The first plasmid cloning vectors required some restriction enzyme sites that were present in only one copy on the plasmid.

Question 64

Mutations in a cell can occur in the absence of selective pressure.

Question 65

The enzyme ___________ hydrolyzes the chromogenic substrate X-gal.

A)α-amylase
B)β-lactamase
C)xylanase
D)β-galactosidase
E)glucuronidase