Question 1

The mechanism by which genes are transferred into bacteria via viruses is called

Accepted Answer

A)  ellipsis.
B)  replica plating.
C)  transformation.
D)  transduction.
E)  conjugation.

Question 2

Some bacteria have a higher incidence rate of thymine dimer mutations following exposure to UV light than others. What might be going on here to lead to this outcome?

Accepted Answer

A)  They may simply have a higher proportion of T nucleotides next to each other in their DNA sequences than other bacteria, leading to more possible dimers being formed.
B)  They may have a stronger expression of photoreactivation enzymes, leading to more thymine dimers being formed and retained.
C)  They may have a weaker expression of photoreactivation enzymes, leading to more thymine dimers being formed and retained.
D)  They may simply have a higher proportion of T nucleotides next to each other in their DNA sequences than other bacteria, leading to more possible dimers being formed AND they may have a stronger expression of photoreactivation enzymes, leading to more thymine dimers being formed and retained.
E)  They may simply have a higher proportion of T nucleotides next to each other in their DNA sequences than other bacteria, leading to more possible dimers being formed AND they may have a weaker expression of photoreactivation enzymes, leading to more thymine dimers being formed and retained.

Question 3

Chemical mutagens often act by altering the

Accepted Answer

A)  alkyl groups of the nitrogen bases.
B)  nitrogen base sequence.
C)  number of binding sites on the nitrogen bases.
D)  hydrogen bonding properties of the nitrogen bases.

Question 4

DNA transfer by conjugation is more efficient in a liquid medium setting, subjected to very mild agitation (stirring) , rather than on an agar plate format. Why?

Accepted Answer

A)  Direct cell-to-cell contact is required for this process, and this is more likely to be achieved in the plate format than in the fluid format (especially for relatively non-motile types of bacteria) .
B)  Direct cell-to-cell contact isn't required for this process, so the ability to secrete the DNA into the surrounding fluid medium makes the process more efficient than the dry surface of an agar plate.
C)  Direct cell-to-cell contact is required for this process, and this is more likely to be achieved in the fluid liquid format than on an agar plate (especially for relatively non-motile types of bacteria) .
D)  Trick question-it can take place with the same degree of efficiency on either format.It doesn't matter!

Question 5

Thymine dimers are dealt with by

Accepted Answer

A)  no repair mechanisms.
B)  photoreactivation repair.
C)  SOS repair.
D)  excision repair.
E)  photoreactivation repair AND excision repair.

Question 6

The characteristics displayed by an organism in any given environment is its

Accepted Answer

A)  genotype.
B)  archaetype.
C)  mutatotype.
D)  phenotype.

Question 7

Mutations are likely to persist after SOS repair, but not after light-induced or excision repair.

Accepted Answer

A) True 
 B)False

Question 8

The Ames test is useful as a rapid screening test to identify those compounds that

Accepted Answer

A)  will respond to chemical agents.
B)  have a high probability of being carcinogenic.
C)  respond to the deletion of DNases.
D)  will protect an organism from cancer.
E)  will respond to chemical agents AND will protect an organism from cancer.

Question 9

Organisms termed his- are considered prototrophic for histidine.

Accepted Answer

A) True 
 B)False

Question 10

The formation of a covalent bond between two adjacent thymines is caused by

Accepted Answer

A)  mustard gas.
B)  alkylating agents.
C)  microwave radiation.
D)  UV radiation.

Question 11

The diploid character of eukaryotic cells may mask the appearance of a mutation since

Accepted Answer

A)  this may be a frame shift.
B)  the mutation is often reversible.
C)  the mutation may be palindromic.
D)  the matching chromosome may carry the dominant gene.

Question 12

To increase the chance of detecting carcinogens in the Ames Test, the test substance is treated with

Accepted Answer

A)  penicillin.
B)  heat.
C)  ground up rat liver.
D)  reverse transcriptase.
E)  penicillin AND heat.

Question 13

In conjugation, transformation, or transduction, the recipient bacteria is most likely to accept donor DNA

Accepted Answer

A)  from any source.
B)  from any species of bacteria.
C)  from the same species of bacteria.
D)  only through plasmids.
E)  from any source AND only through plasmids.

Question 14

Prokaryotic cell mutations can be observed very quickly because the prokaryotic chromosome is

Accepted Answer

A)  diploid.
B)  polyploid.
C)  haploid.
D)  polysomal.

Question 15

The study of the crown gall tumor found

Accepted Answer

A)  a bacterial plasmid promoter that was similar to plant promoters.
B)  an R plasmid.
C)  incorporation of the bacterial chromosome into the plant.
D)  incorporation of the plant chromosome into the bacteria.

Question 16

A quick microbiological test for potential carcinogens was developed by

Accepted Answer

A)  Fleming.
B)  Lederberg.
C)  Ames.
D)  Crick.

Question 17

Gene transfer that requires cell-to-cell contact is

Accepted Answer

A)  transformation.
B)  competency.
C)  conjugation.
D)  functional genomics.

Question 18

The properties of a cell which are determined by its DNA composition are its

Accepted Answer

A)  phenotype.
B)  genotype.
C)  metabolism.
D)  nucleoid.

Question 19

The transfer of vancomycin resistance from Enterococcus faecalis to Staphylococcus aureus is thought to have involved

Accepted Answer

A)  conjugation.
B)  transformation.
C)  transduction.
D)  transposons.
E)  conjugation AND transposons.

Question 20

Strong chemical mutagens may be used to treat cancer cells. Is this a good or bad idea?

Accepted Answer

A)  Good-kill those cancer cells as quickly as possible to cure the patient!
B)  Bad-these mutagens will also affect the non-cancerous cells, possibly leading to new cancerous states!
C)  Good and bad-they're very good at killing cancer cells, but depending on mode of administration, they could also be dangerous to non-cancerous cells.
D)  Bad-the cancer cells are already mutated.We don't want to mutate them more and make them more cancerous!

Exam 8: Bacterial Genetics

Prokaryotic cell mutations can be observed very quickly because the prokaryotic chromosome is

Correct AnswerverifiedShow Answer

The formation of a covalent bond between two adjacent thymines is caused by

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Some bacteria have a higher incidence rate of thymine dimer mutations following exposure to UV light than others. What might be going on here to lead to this outcome?

Correct AnswerverifiedShow Answer

To increase the chance of detecting carcinogens in the Ames Test, the test substance is treated with

Correct AnswerverifiedShow Answer

The diploid character of eukaryotic cells may mask the appearance of a mutation since

Correct AnswerverifiedShow Answer

Chemical mutagens often act by altering the

Correct AnswerverifiedShow Answer

In conjugation, transformation, or transduction, the recipient bacteria is most likely to accept donor DNA

Correct AnswerverifiedShow Answer

Gene transfer that requires cell-to-cell contact is

Correct AnswerverifiedShow Answer

The characteristics displayed by an organism in any given environment is its

Correct AnswerverifiedShow Answer

The study of the crown gall tumor found

Correct AnswerverifiedShow Answer

A quick microbiological test for potential carcinogens was developed by

Correct AnswerverifiedShow Answer

DNA transfer by conjugation is more efficient in a liquid medium setting, subjected to very mild agitation (stirring) , rather than on an agar plate format. Why?

Correct AnswerverifiedShow Answer

Thymine dimers are dealt with by

Correct AnswerverifiedShow Answer

The properties of a cell which are determined by its DNA composition are its

Correct AnswerverifiedShow Answer

The transfer of vancomycin resistance from Enterococcus faecalis to Staphylococcus aureus is thought to have involved

Correct AnswerverifiedShow Answer

Strong chemical mutagens may be used to treat cancer cells. Is this a good or bad idea?

Correct AnswerverifiedShow Answer

Mutations are likely to persist after SOS repair, but not after light-induced or excision repair.

Correct AnswerverifiedShow Answer

The mechanism by which genes are transferred into bacteria via viruses is called

Correct AnswerverifiedShow Answer

The Ames test is useful as a rapid screening test to identify those compounds that

Correct AnswerverifiedShow Answer

Organisms termed his- are considered prototrophic for histidine.

Correct AnswerverifiedShow Answer

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Organisms termed his^- are considered prototrophic for histidine.

Correct Answer
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