Question 1

Which is True about a crown gall tumor?

Accepted Answer

A)  It is a unique viral infection of plants. 
B)  It results from the transfer of a transposon to the plant. 
C)  It results from an Agrogallerium infection of the plant. 
D)  It results from the incorporation of bacterial plasmid DNA into the plant chromosome. 
E)  It results from the incorporation of plant plasmid DNA into the bacterial chromosome. 
A)  It is a unique viral infection of plants. 
B)  It results from the transfer of a transposon to the plant. 
C)  It results from an Agrogallerium infection of the plant. 
D)  It results from the incorporation of bacterial plasmid DNA into the plant chromosome. 
E)  It results from the incorporation of plant plasmid DNA into the bacterial chromosome.

Question 2

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! 
E)  Agitation is only needed if the bacteria are known to be non-motile and can't move around on a solid medium. Otherwise, it doesn't really matter what type of medium is used as long as it contains chemicals to make cells competent. 
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! 
E)  Agitation is only needed if the bacteria are known to be non-motile and can't move around on a solid medium. Otherwise, it doesn't really matter what type of medium is used as long as it contains chemicals to make cells competent.

Question 3

Insertion sequences

Accepted Answer

A)  are the simplest type of transposon, code for a transposase enzyme AND can produce pili. 
B)  code for a transposase enzyme AND are characterized by an inverted repeat. 
C)  are characterized by an inverted repeat AND can produce pili. 
D)  can produce pili AND are the simplest type of transposon. 
E)  are the simplest type of transposon, code for a transposase enzyme, AND are characterized by an inverted repeat. 
A)  are the simplest type of transposon, code for a transposase enzyme AND can produce pili. 
B)  code for a transposase enzyme AND are characterized by an inverted repeat. 
C)  are characterized by an inverted repeat AND can produce pili. 
D)  can produce pili AND are the simplest type of transposon. 
E)  are the simplest type of transposon, code for a transposase enzyme, AND are characterized by an inverted repeat.

Question 4

Segments of DNA capable of moving from one area in the DNA to another are called

Accepted Answer

A)  base analogs. 
B)  intercalating agents. 
C)  transposons. 
D)  inverted repeats. 
E)  mutagens. 
A)  base analogs. 
B)  intercalating agents. 
C)  transposons. 
D)  inverted repeats. 
E)  mutagens.

Question 5

The designation his⁻ refers to

Accepted Answer

A)  the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine. 
B)  the genotype of bacteria that have a functional gene for histidine synthesis AND bacteria that require addition of histidine to the growth medium. 
C)  the genotype of bacteria that have a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine. 
D)  the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that have a hers gene. 
E)  the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that do not require addition of histidine to the growth medium. 
A)  the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine. 
B)  the genotype of bacteria that have a functional gene for histidine synthesis AND bacteria that require addition of histidine to the growth medium. 
C)  the genotype of bacteria that have a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine. 
D)  the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that have a hers gene. 
E)  the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that do not require addition of histidine to the growth medium.

Question 6

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. 
-On further reading, you learn that strains of H. influenzae vary genotypically. Many of them have silent mutations. Select the True statement regarding this type of mutation.

Accepted Answer

A)  It is a point mutation-a single base pair is altered, causing the change of one amino acid in the protein that changes the function of that protein. 
B)  It is a point mutation-a single base pair is altered, causing the change of one amino acid in the protein that stops the correct formation of a protein. 
C)  It is a point mutation-a single base pair is altered, causing the change of one amino acid in the protein that does not affect the function of that protein. 
D)  It is a frameshift mutation-base pairs are added or deleted, causing the change of one or more amino acids in the protein but does not affect the function of that protein. 
E)  It is a point mutation-several base pairs are altered, causing the change of many amino acids in the protein that completely changes the function of that protein. 
A)  It is a point mutation-a single base pair is altered, causing the change of one amino acid in the protein that changes the function of that protein. 
B)  It is a point mutation-a single base pair is altered, causing the change of one amino acid in the protein that stops the correct formation of a protein. 
C)  It is a point mutation-a single base pair is altered, causing the change of one amino acid in the protein that does not affect the function of that protein. 
D)  It is a frameshift mutation-base pairs are added or deleted, causing the change of one or more amino acids in the protein but does not affect the function of that protein. 
E)  It is a point mutation-several base pairs are altered, causing the change of many amino acids in the protein that completely changes the function of that protein.

Question 7

A patient comes to see you complaining of a spider bite. He shows you a sore on his wrist—the area around it is red and swollen, and the lesion is leaking pus. The patient tells you he found a spider in his car, which is why he thinks this is a bite. He also tells you that he has been taking penicillin tablets that his wife had left over after being prescribed the drug a few months previously for pneumonia. Even though he has taken the tablets for four days, the lesion is not healing and that he is really feeling terrible, with pain, fever, and chills. You suspect that your patient has a wound infection, so you sample the pus and send it to the lab for analysis.
-Your patient asks whether there is any way for him to get rid of this infection. You tell him that he will be given a different antibiotic such as doxycycline. This antibiotic works by binding to a cell structure called the 30S ribosomal subunit, which stops the bacterial cells from growing by

Accepted Answer

A)  preventing DNA replication. 
B)  inhibiting transcription. 
C)  stopping capsule formation. 
D)  inhibiting protein synthesis. 
E)  preventing protein packaging. 
A)  preventing DNA replication. 
B)  inhibiting transcription. 
C)  stopping capsule formation. 
D)  inhibiting protein synthesis. 
E)  preventing protein packaging.

Question 8

A patient comes to see you complaining of a spider bite. He shows you a sore on his wrist—the area around it is red and swollen, and the lesion is leaking pus. The patient tells you he found a spider in his car, which is why he thinks this is a bite. He also tells you that he has been taking penicillin tablets that his wife had left over after being prescribed the drug a few months previously for pneumonia. Even though he has taken the tablets for four days, the lesion is not healing and that he is really feeling terrible, with pain, fever, and chills. You suspect that your patient has a wound infection, so you sample the pus and send it to the lab for analysis.
-Your patient asks why the penicillin he has been taking hasn't helped his infection. Which of the following is a possible explanation for your patient?

Accepted Answer

A)  The patient has become resistant to penicillin and he needs to take a different medication. 
B)  The bacteria causing the infection are resistant to penicillin; a different antibiotic is needed. 
C)  Bacteria are never killed by a single type of antibiotic; combinations of drugs are needed. 
D)  Penicillin has been overused by people and it no longer works against any bacteria; it can be used against viruses. 
E)  The patient's body is neutralizing the antibiotic; he needs to take a probiotic to help the penicillin work. 
A)  The patient has become resistant to penicillin and he needs to take a different medication. 
B)  The bacteria causing the infection are resistant to penicillin; a different antibiotic is needed. 
C)  Bacteria are never killed by a single type of antibiotic; combinations of drugs are needed. 
D)  Penicillin has been overused by people and it no longer works against any bacteria; it can be used against viruses. 
E)  The patient's body is neutralizing the antibiotic; he needs to take a probiotic to help the penicillin work.

Question 9

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

Accepted Answer

A)  X-rays. 
B)  alkylating agents. 
C)  UV radiation. 
D)  microwave radiation. 
E)  heat. 
A)  X-rays. 
B)  alkylating agents. 
C)  UV radiation. 
D)  microwave radiation. 
E)  heat.

Question 10

If you were carrying out a penicillin enrichment culture and you forgot to add penicillinase before plating the sample onto nutrient agar, what would happen?

Accepted Answer

A)  You would get the same results whether you add this enzyme of not because penicillin naturally rapidly degrades in agar. 
B)  The prototrophs would be able to grow on the agar plates but the auxotrophs would not. 
C)  The auxotrophs would be able to grow on the agar plates but the prototrophs would not. 
D)  Prototrophs and auxotrophs would both be killed by the penicillin; only Penᴿ mutants would grow and you would not enrich for auxotrophs. 
E)  Prototroph and auxotroph colonies would change color from cream to red in the presence of the penicillin. 
A)  You would get the same results whether you add this enzyme of not because penicillin naturally rapidly degrades in agar. 
B)  The prototrophs would be able to grow on the agar plates but the auxotrophs would not. 
C)  The auxotrophs would be able to grow on the agar plates but the prototrophs would not. 
D)  Prototrophs and auxotrophs would both be killed by the penicillin; only Penᴿ mutants would grow and you would not enrich for auxotrophs. 
E)  Prototroph and auxotroph colonies would change color from cream to red in the presence of the penicillin.

Question 11

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

Accepted Answer

A)  will respond to chemical agents. 
B)  are mutagens. 
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. 
A)  will respond to chemical agents. 
B)  are mutagens. 
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 12

The largest group of chemical mutagens consists of

Accepted Answer

A)  radiation. 
B)  alkylating agents. 
C)  nitrous acid. 
D)  base analogs. 
E)  intercalating agents. 
A)  radiation. 
B)  alkylating agents. 
C)  nitrous acid. 
D)  base analogs. 
E)  intercalating agents.

Question 13

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. 
-H. influenzae has genes that it needs to make pili for attachment to host cells. These pili genes are not always expressed; sometimes the bacterium turns them off and does not produce pili. This is an example of

Accepted Answer

A)  phase variation. 
B)  antigenic sensing. 
C)  two-component control. 
D)  transduction. 
E)  gene splicing. 
A)  phase variation. 
B)  antigenic sensing. 
C)  two-component control. 
D)  transduction. 
E)  gene splicing.

Question 14

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

Accepted Answer

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

Question 15

The F plasmid carries the information for

Accepted Answer

A)  the sex pilus. 
B)  recipient cell DNA replication. 
C)  antibiotic resistance. 
D)  the Y chromosome. 
E)  bacterial flagella. 
A)  the sex pilus. 
B)  recipient cell DNA replication. 
C)  antibiotic resistance. 
D)  the Y chromosome. 
E)  bacterial flagella.

Question 16

Which change in a gene's DNA sequence would have the least effect on the eventual amino acid sequence produced from it?

Accepted Answer

A)  Deletion of two consecutive nucleotides 
B)  Addition of one nucleotide 
C)  Addition or deletion of three consecutive nucleotides 
D)  Substitution of one nucleotide AND addition of one nucleotide 
E)  Addition of two consecutive nucleotides 
A)  Deletion of two consecutive nucleotides 
B)  Addition of one nucleotide 
C)  Addition or deletion of three consecutive nucleotides 
D)  Substitution of one nucleotide AND addition of one nucleotide 
E)  Addition of two consecutive nucleotides

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

You mix two bacterial stains in a tube of glucose-salts agar. One strain is His−, Val−, while the other strain is Trp−, Leu−. You previously showed that neither strain grows on glucose-salts agar. After incubating the tube, you plate a sample onto a new glucose-salts agar plate. Several colonies grow. What do you know is True about these colonies?

Accepted Answer

A)  The bacteria in the colonies are His−, Val−, Trp⁺, Leu⁺. 
B)  The bacteria in the colonies are His−, Val⁺, Trp⁺, Leu⁺. 
C)  The bacteria in the colonies are His−, Val−, Trp−, Leu−. 
D)  The bacteria in the colonies are His⁺, Val⁺, Trp⁺, Leu⁺. 
E)  The bacteria in the colonies are His⁺, Val⁺, Trp⁺, Leu⁺, Penᴿ. 
A)  The bacteria in the colonies are His−, Val−, Trp⁺, Leu⁺. 
B)  The bacteria in the colonies are His−, Val⁺, Trp⁺, Leu⁺. 
C)  The bacteria in the colonies are His−, Val−, Trp−, Leu−. 
D)  The bacteria in the colonies are His⁺, Val⁺, Trp⁺, Leu⁺. 
E)  The bacteria in the colonies are His⁺, Val⁺, Trp⁺, Leu⁺, Penᴿ.

Question 19

Intercalating agents

Accepted Answer

A)  act during RNA synthesis AND often result in frameshift mutations. 
B)  act during RNA synthesis AND change the hydrogen bonding properties of nucleotides. 
C)  act during DNA synthesis AND often result in frameshift mutations. 
D)  change the hydrogen bonding properties of nucleotides AND always result in nonsense mutations. 
E)  act during DNA synthesis AND always result in nonsense mutations. 
A)  act during RNA synthesis AND often result in frameshift mutations. 
B)  act during RNA synthesis AND change the hydrogen bonding properties of nucleotides. 
C)  act during DNA synthesis AND often result in frameshift mutations. 
D)  change the hydrogen bonding properties of nucleotides AND always result in nonsense mutations. 
E)  act during DNA synthesis AND always result in nonsense mutations.

Question 20

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

Accepted Answer

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

Exam 8: Bacterial Genetics

Which is True about a crown gall tumor?

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?

Insertion sequences

Segments of DNA capable of moving from one area in the DNA to another are called

The designation his⁻ refers to

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

If you were carrying out a penicillin enrichment culture and you forgot to add penicillinase before plating the sample onto nutrient agar, what would happen?

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

The largest group of chemical mutagens consists of

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

The F plasmid carries the information for

Which change in a gene's DNA sequence would have the least effect on the eventual amino acid sequence produced from it?

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

Intercalating agents

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

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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