Question 1

The incorporation of a single strand of donor DNA into a recipient DNA duplex so that the donor strand replaces one of the strands or the recipient duplex generates __________ DNA.

Accepted Answer

A)  aberrant
B)  unstable
C)  heterogeneous
D)  heteroduplex

Question 2

The transformation frequency of very competent cells is about 10-6,or about 1 in 1,000,000 when an excess of DNA is used.

Accepted Answer

A) True 
 B)False

Question 3

_______ are strains that are unable to grow on a minimal medium that supports growth of the wild type strain,but are able to grow on the minimal medium if one or more nutritional supplements are added.

Accepted Answer

A)  Autotrophs
B)  Auxotrophs
C)  Prototrophs
D)  Minitrophs

Question 4

__________ are physical or chemical agents that cause mutation.

Accepted Answer

The answer of __________ are physical or chemical agents that...

Question 5

As the result of exposure to a mutagen,cytosine is substituted for thymine in one strand of DNA.Upon subsequent DNA replication,one of the daughter cells will have a GC pair in this position instead of an AT pair.This is called a(n) __________ mutation.

Accepted Answer

A)  transversion
B)  transition
C)  frameshift
D)  insertion

Question 6

A change in genotype,but not in phenotype,is most likely due to

Accepted Answer

A)  a nonsense mutation at the beginning of a gene.
B)  a point mutation in the third position of a DNA triplet.
C)  a mutation that leads to a frameshift in the middle of a gene.
D)  thymine dimer formation in the coding region of a gene.

Question 7

A reciprocal exchange in which a pair of DNA with the same nucleotide sequence break and rejoin in a crossover is called __________ recombination.

Accepted Answer

A)  homologous
B)  site-specific
C)  replicative
D)  None of the choices are correct.

Question 8

Which of the following is not a strategy that bacteria use to resist the action of antibiotics?

Accepted Answer

A)  Modification of the antibiotic by the acetylation or phosphorylation.
B)  Cleavage of a key structural component of the antibiotic.
C)  Altering cell membrane structure to prevent antibiotic influx.
D)  All of the choices are correct.

Question 9

A mutation from the most prevalent form of a gene to a mutant form is called a __________ mutation.

Accepted Answer

A)  forward
B)  reverse
C)  wild card
D)  escalating

Question 10

Which of the following types of mutation may play an important role in driving evolution because they are often nonlethal and,therefore,remain in the gene pool?

Accepted Answer

A)  Nonsense
B)  Missense
C)  Frameshift
D)  Deletion

Question 11

A public health microbiologist plans to screen a particular bacterial species that was isolated from several patients in an intensive care unit to detect if any of the cells are penicillin-resistant mutants.What is the first step in conducting this experiment?

Accepted Answer

A)  Determine whether or not wild type cells of the same bacterial species are susceptible to penicillin.
B)  Test the cells to see if they can grow on media to which penicillin has been added.
C)  Perform an antibiotic susceptibility test on the cells using antibiotics other than penicillin that are known to be effective.
D)  Set up an Ames test to see if any of the isolates are mutagenic.

Question 12

Plasmids that have genes that decrease bacterial susceptibility to antibiotics are called __________ factors.

Accepted Answer

A)  col
B)  resistance
C)  virulence
D)  metabolic

Question 13

In an HFR * F+ mating,the conjugation bridge usually breaks before chromosomal transfer is complete.Therefore,the recipient remains F-.

Accepted Answer

A) True 
 B)False

Question 14

In an F+ * F- conjugation,the donor is the __________ strain.

Accepted Answer

A)  F+
B)  F-
C)  both F+ and F- (It is a reciprocal exchange) 
D)  neither F+ nor F- (There is no exchange)

Question 15

If 5-bromouracil was added to a culture of actively dividing bacterial cells,resulting mutations could eventually become a stable part of the cellular genome.

Accepted Answer

A) True 
 B)False

Question 16

__________ mutations affect only a single base pair in a gene.

Accepted Answer

The answer of __________ mutations affect only a single base...

Question 17

Predict the outcome of protein synthesis if a gene undergoes a mutation in its anticodon region where a charged tRNA recognizes a nonsense mutation

Accepted Answer

A)  Transcription and translation both would continue.
B)  Transcription would continue but translation would not continue.
C)  Transcription and translation both would not continue.
D)  Transcription would continue but translation would not continue

Question 18

Transfer of genes from one mature independent organism to another is called

Accepted Answer

A)  horizontal gene transfer.
B)  lateral gene transfer.
C)  vertical gene transfer.
D)  orthogonal gene transfer.

Question 19

Lethal mutations can be maintained in diploid organisms if they are

Accepted Answer

A)  dominant.
B)  recessive.
C)  deletions.
D)  None of the choices are correct.

Question 20

Transposable elements have been found only in prokaryotes and do not appear to play a major role in eukaryotes.

Accepted Answer

A) True 
 B)False

Exam 16: Mechanisms of Genetic Variation

If 5-bromouracil was added to a culture of actively dividing bacterial cells,resulting mutations could eventually become a stable part of the cellular genome.

Correct AnswerverifiedShow Answer

In an HFR * F+ mating,the conjugation bridge usually breaks before chromosomal transfer is complete.Therefore,the recipient remains F-.

Correct AnswerverifiedShow Answer

As the result of exposure to a mutagen,cytosine is substituted for thymine in one strand of DNA.Upon subsequent DNA replication,one of the daughter cells will have a GC pair in this position instead of an AT pair.This is called a(n) __________ mutation.

Correct AnswerverifiedShow Answer

Transfer of genes from one mature independent organism to another is called

Correct AnswerverifiedShow Answer

Predict the outcome of protein synthesis if a gene undergoes a mutation in its anticodon region where a charged tRNA recognizes a nonsense mutation

Correct AnswerverifiedShow Answer

Transposable elements have been found only in prokaryotes and do not appear to play a major role in eukaryotes.

Correct AnswerverifiedShow Answer

__________ are physical or chemical agents that cause mutation.

Correct AnswerverifiedShow Answer

A public health microbiologist plans to screen a particular bacterial species that was isolated from several patients in an intensive care unit to detect if any of the cells are penicillin-resistant mutants.What is the first step in conducting this experiment?

Correct AnswerverifiedShow Answer

Lethal mutations can be maintained in diploid organisms if they are

Correct AnswerverifiedShow Answer

The incorporation of a single strand of donor DNA into a recipient DNA duplex so that the donor strand replaces one of the strands or the recipient duplex generates __________ DNA.

Correct AnswerverifiedShow Answer

A change in genotype,but not in phenotype,is most likely due to

Correct AnswerverifiedShow Answer

__________ mutations affect only a single base pair in a gene.

Correct AnswerverifiedShow Answer

A reciprocal exchange in which a pair of DNA with the same nucleotide sequence break and rejoin in a crossover is called __________ recombination.

Correct AnswerverifiedShow Answer

Which of the following is not a strategy that bacteria use to resist the action of antibiotics?

Correct AnswerverifiedShow Answer

Which of the following types of mutation may play an important role in driving evolution because they are often nonlethal and,therefore,remain in the gene pool?

Correct AnswerverifiedShow Answer

_______ are strains that are unable to grow on a minimal medium that supports growth of the wild type strain,but are able to grow on the minimal medium if one or more nutritional supplements are added.

Correct AnswerverifiedShow Answer

The transformation frequency of very competent cells is about 10-6,or about 1 in 1,000,000 when an excess of DNA is used.

Correct AnswerverifiedShow Answer

Plasmids that have genes that decrease bacterial susceptibility to antibiotics are called __________ factors.

Correct AnswerverifiedShow Answer

A mutation from the most prevalent form of a gene to a mutant form is called a __________ mutation.

Correct AnswerverifiedShow Answer

In an F+ * F- conjugation,the donor is the __________ strain.

Correct AnswerverifiedShow Answer

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In an HFR * F⁺ mating,the conjugation bridge usually breaks before chromosomal transfer is complete.Therefore,the recipient remains F^-.

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The transformation frequency of very competent cells is about 10^-6,or about 1 in 1,000,000 when an excess of DNA is used.

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In an F⁺ * F^- conjugation,the donor is the __________ strain.

Correct Answer
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