Question 1

Two bacterial genes are transduced simultaneously. What does this suggest about their proximity to each other within the original host genome?

Accepted Answer

A)  Nothing. It's highly likely that two separate virus particles were carrying each gene, and that they coinfected the new target cell at the same time. This could mean the two original genes might not even be from the same original host cell! 
B)  It's highly likely that the two genes are located next to each other in the host cell chromosome. Since transduction results from a packaging error or an excision error that occurs during the infection cycle of the bacteriophage, the genes must lie close to each other to be transduced into a new cell simultaneously. 
C)  They must be within five gene lengths of each other, but not necessarily immediately adjacent. If they were immediately adjacent, the transposons that facilitate the transfer of genetic information between the two cells wouldn't be able to "jump" into them. 
D)  It doesn't mean anything. Transduction relies on the ability of a cell to take up foreign DNA. It's possible here that the cell has simply taken up two separate bits of DNA at the same time from the surrounding environment. 
E)  It's highly likely that one gene was on the chromosome but the other was actually on a plasmid; if those two elements are in one cell, genes can be transferred simultaneously. 
A)  Nothing. It's highly likely that two separate virus particles were carrying each gene, and that they coinfected the new target cell at the same time. This could mean the two original genes might not even be from the same original host cell! 
B)  It's highly likely that the two genes are located next to each other in the host cell chromosome. Since transduction results from a packaging error or an excision error that occurs during the infection cycle of the bacteriophage, the genes must lie close to each other to be transduced into a new cell simultaneously. 
C)  They must be within five gene lengths of each other, but not necessarily immediately adjacent. If they were immediately adjacent, the transposons that facilitate the transfer of genetic information between the two cells wouldn't be able to "jump" into them. 
D)  It doesn't mean anything. Transduction relies on the ability of a cell to take up foreign DNA. It's possible here that the cell has simply taken up two separate bits of DNA at the same time from the surrounding environment. 
E)  It's highly likely that one gene was on the chromosome but the other was actually on a plasmid; if those two elements are in one cell, genes can be transferred simultaneously.

Question 2

In conjugation the donor cell is recognized by the presence of

Accepted Answer

A)  an F plasmid. 
B)  a Y chromosome. 
C)  diploid chromosomes. 
D)  an SOS response. 
E)  an F plasmid AND diploid chromosomes. 
A)  an F plasmid. 
B)  a Y chromosome. 
C)  diploid chromosomes. 
D)  an SOS response. 
E)  an F plasmid AND diploid chromosomes.

Question 3

Organisms termed his⁻ are considered prototrophic for histidine.

Accepted Answer

A) True 
 B)False

Question 4

Chemical mutagens often act by altering the

Accepted Answer

A)  alkyl groups of the nucleobase. 
B)  nucleobase sequence. 
C)  number of binding sites on the nucleobase. 
D)  hydrogen bonding properties of the nucleobase. 
E)  nucleobases. 
A)  alkyl groups of the nucleobase. 
B)  nucleobase sequence. 
C)  number of binding sites on the nucleobase. 
D)  hydrogen bonding properties of the nucleobase. 
E)  nucleobases.

Question 5

DNA is protected from restriction enzymes by being

Accepted Answer

A)  sequestered in a lysosome. 
B)  turned into RNA. 
C)  methylated. 
D)  made into double-stranded RNA. 
E)  phosphorylated. 
A)  sequestered in a lysosome. 
B)  turned into RNA. 
C)  methylated. 
D)  made into double-stranded RNA. 
E)  phosphorylated.

Question 6

To increase the proportion of auxotrophic mutants in a population of bacteria, one may use

Accepted Answer

A)  direct selection. 
B)  replica plating. 
C)  penicillin enrichment. 
D)  individual transfer. 
E)  mutant reversion. 
A)  direct selection. 
B)  replica plating. 
C)  penicillin enrichment. 
D)  individual transfer. 
E)  mutant reversion.

Question 7

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

Question 8

To maximize the number of thymine dimer mutations following UV exposure, should you keep human cells in tissue culture in the dark, in the light, or does it matter at all?

Accepted Answer

A)  The dark-light will activate the photorepair systems that can break thymine dimers induced by UV light. 
B)  The light-it's important to keep on producing the thymine dimers by keeping the plate exposed to light as much as possible. 
C)  Alternating light and dark every hour to increase the chances that thymine dimers will form, but prevent photorepair systems from correcting them as they are formed. 
D)  It doesn't matter-human cells don't have the enzymes needed for photorepair of thymine dimers. 
E)  Alternating light and dark every 24 hours to increase the chances that thymine dimers will form. 
A)  The dark-light will activate the photorepair systems that can break thymine dimers induced by UV light. 
B)  The light-it's important to keep on producing the thymine dimers by keeping the plate exposed to light as much as possible. 
C)  Alternating light and dark every hour to increase the chances that thymine dimers will form, but prevent photorepair systems from correcting them as they are formed. 
D)  It doesn't matter-human cells don't have the enzymes needed for photorepair of thymine dimers. 
E)  Alternating light and dark every 24 hours to increase the chances that thymine dimers will form.

Question 9

Among the easiest of the mutations to isolate are those which

Accepted Answer

A)  involve polyploid chromosomes AND allow populations to be measured. 
B)  involve antibiotic resistance AND allow populations to be measured. 
C)  allow populations to be measured AND use an indirect method for measurement. 
D)  involve haploid chromosomes AND involve antibiotic resistance. 
E)  use an indirect method for measurement AND involve antibiotic resistance. 
A)  involve polyploid chromosomes AND allow populations to be measured. 
B)  involve antibiotic resistance AND allow populations to be measured. 
C)  allow populations to be measured AND use an indirect method for measurement. 
D)  involve haploid chromosomes AND involve antibiotic resistance. 
E)  use an indirect method for measurement AND involve antibiotic resistance.

Question 10

Each gene mutates at a characteristic frequency.

Accepted Answer

A) True 
 B)False

Question 11

A bacterial strain is resistant to infection by a bacteriophage. Which statement is False?

Accepted Answer

A)  The bacteria make restriction enzymes that degrade the virus genome. 
B)  The bacterial host DNA is protected from restriction enzyme degradation by phosphorylation. 
C)  The bacterial host DNA is protected from restriction enzyme degradation by methylation. 
D)  If the phage DNA was methylated, it would be protected from restriction enzyme degradation. 
E)  The statements are ALL False. 
A)  The bacteria make restriction enzymes that degrade the virus genome. 
B)  The bacterial host DNA is protected from restriction enzyme degradation by phosphorylation. 
C)  The bacterial host DNA is protected from restriction enzyme degradation by methylation. 
D)  If the phage DNA was methylated, it would be protected from restriction enzyme degradation. 
E)  The statements are ALL False.

Question 12

In order for insertional inactivation to occur, the transposon must be placed

Accepted Answer

A)  upstream from the gene in question. 
B)  downstream from the gene in question. 
C)  within the gene in question. 
D)  randomly in the genome. 
E)  in an intron. 
A)  upstream from the gene in question. 
B)  downstream from the gene in question. 
C)  within the gene in question. 
D)  randomly in the genome. 
E)  in an intron.

Question 13

Antibiotics

Accepted Answer

A)  cause mutations to occur. 
B)  may act as alkylating mutagens. 
C)  provide an environment in which preexisting mutants survive. 
D)  increase the rate of spontaneous mutation. 
E)  destroy all mutant bacteria. 
A)  cause mutations to occur. 
B)  may act as alkylating mutagens. 
C)  provide an environment in which preexisting mutants survive. 
D)  increase the rate of spontaneous mutation. 
E)  destroy all mutant bacteria.

Question 14

You are a volunteer for Nurses Without Borders and are being sent on a humanitarian mission. You are somewhat concerned because you have learned from the CDC website that antibiotic-resistant Haemophilus influenzae is common in the country to which you are being sent. This encapsulated, Gram-negative bacterium can cause a variety of illnesses, including community-acquired pneumonia. You do some research on the genetics of this pathogen. 
-What concerns you most about the strain of H. influenzae that you may be exposed to while you are away is antibiotic resistance. The genes for resistance can be acquired by this organism as naked DNA from the environment, an example of

Accepted Answer

A)  conjugation. 
B)  transformation. 
C)  induced mutation. 
D)  vertical gene transfer. 
E)  transduction. 
A)  conjugation. 
B)  transformation. 
C)  induced mutation. 
D)  vertical gene transfer. 
E)  transduction.

Question 15

Plasmids often carry the information for antibiotic resistance.

Accepted Answer

A) True 
 B)False

Question 16

Every 24 hours, every genome in every cell of the human body is damaged 10,000 times or more. Given the possible DNA repair mechanisms, which order listed below would be most effective at repairing these as quickly as possible in order to prevent mutations from being carried forward in DNA replication?

Accepted Answer

A)  Proofreading by DNA polymerase, glycosylase enzyme activities, excision repair, SOS repair 
B)  SOS repair, excision repair, glycosylase enzyme activities, proofreading by DNA polymerase 
C)  SOS repair, proofreading by DNA polymerase, glycosylase enzyme activities, excision repair 
D)  Glycosylase enzyme activities, SOS repair, proofreading by DNA polymerase, excision repair 
E)  Proofreading by DNA polymerase, SOS repair, glycosylase enzyme activities, excision repair 
A)  Proofreading by DNA polymerase, glycosylase enzyme activities, excision repair, SOS repair 
B)  SOS repair, excision repair, glycosylase enzyme activities, proofreading by DNA polymerase 
C)  SOS repair, proofreading by DNA polymerase, glycosylase enzyme activities, excision repair 
D)  Glycosylase enzyme activities, SOS repair, proofreading by DNA polymerase, excision repair 
E)  Proofreading by DNA polymerase, SOS repair, glycosylase enzyme activities, excision repair

Question 17

Bacteria that have properties of both the donor and recipient cells are the result of

Accepted Answer

A)  UV light. 
B)  SOS repair. 
C)  frame shift mutations. 
D)  genetic recombination. 
E)  antibiotic resistance. 
A)  UV light. 
B)  SOS repair. 
C)  frame shift mutations. 
D)  genetic recombination. 
E)  antibiotic resistance.

Question 18

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

Question 19

DNA repair mechanisms occur

Accepted Answer

A)  only in prokaryotes. 
B)  only in eukaryotes. 
C)  in both eukaryotes and prokaryotes. 
D)  in neither eukaryotes nor prokaryotes. 
E)  None of the answer choices is correct. 
A)  only in prokaryotes. 
B)  only in eukaryotes. 
C)  in both eukaryotes and prokaryotes. 
D)  in neither eukaryotes nor prokaryotes. 
E)  None of the answer choices is correct.

Question 20

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. 
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.

Exam 8: Bacterial Genetics

Two bacterial genes are transduced simultaneously. What does this suggest about their proximity to each other within the original host genome?

In conjugation the donor cell is recognized by the presence of

Organisms termed his⁻ are considered prototrophic for histidine.

Chemical mutagens often act by altering the

DNA is protected from restriction enzymes by being

To increase the proportion of auxotrophic mutants in a population of bacteria, one may use

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

To maximize the number of thymine dimer mutations following UV exposure, should you keep human cells in tissue culture in the dark, in the light, or does it matter at all?

Among the easiest of the mutations to isolate are those which

Each gene mutates at a characteristic frequency.

A bacterial strain is resistant to infection by a bacteriophage. Which statement is False?

In order for insertional inactivation to occur, the transposon must be placed

Antibiotics

Plasmids often carry the information for antibiotic resistance.

Bacteria that have properties of both the donor and recipient cells are the result of

The study of the crown gall tumor found

DNA repair mechanisms occur

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

Humans and the Microbial World

The Molecules of Life

Microscopy and Cell Structure

Dynamics of Microbial Growth

Control of Microbial Growth

Microbial Metabolism: Fueling Cell Growth

The Blueprint of Life, from DNA to Protein

Biotechnology

Identifying and Classifying Microorganisms

The Diversity of Bacteria and Archaea

The Eukaryotic Members of the Microbial World

Viruses, Viroids, and Prions

The Innate Immune Response

The Adaptive Immune Response

Host-Microbe Interactions

Immunological Disorders

Applications of Immune Responses

Epidemiology

Antimicrobial Medications

Respiratory System Infections

Skin Infections

Wound Infections

Digestive System Infections

Blood and Lymphatic Infections

Nervous System Infections

Genitourinary Tract Infections

Microbial Ecology

Environmental Microbiology: Treatment of Water, Wastes, and Polluted Habitats

Food Microbiology

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