Deck 15: Genetics of Viruses and Bacteria

Question 1

You are working in the field with your favorite bacteria species,Bacterium BB.You carry out some experiments with Bacterium BB,and find that it can now degrade toluene and it is pathogenic! What happened?

A)Bacterium BB acquired degradative and virulence plasmids by horizontal gene transfer
B)Bacterium BB picked up fertility and Col-plasmids via conjugation
C)Bacterium BB was exposed to a bacteriophage which is now in its lytic phase
D)Bacterium BB was transformed with a resistance plasmid and a digestive plasmid
E)Bacterium BB sexually reproduced with another strain of bacteria that had both toluene-degrading gene and virulence gene

Answer 1

A

Question 2

How is a typical prokaryotic genome similar to a eukaryotic genome?

A)both are composed of DNA packaged in the nucleus
B)both are composed of double-stranded DNA
C)both are composed of circular chromosomes
D)both are composed of multiple,linear chromosomes
E)both contain chromosome with a single origin of replication

Answer 2

B

Question 3

Lederberg and Tatum's experiments demonstrated that

A)bacteria can acquire genetic material from each other.
B)bacteria do not release DNA into the environment for other bacteria to take up.
C)bacteria must be in physical contact in order for bacteria to exchange genetic material.
D)the genetic transfer occurred when the bio+,met+ phe-thr- strain transferred DNA to the bio-met- strain.
E)All of these observations were made by Lederberg and Tatum.

Answer 3

A

Question 4

How did Davis demonstrate that bacterial cells must be in physical contact in order for genetic exchange to occur?

A)He mixed together two bacteria strains with different nutritional requirements,and then added them to agar plates that lacked their required nutrients.
B)When two bacterial strains with different nutritional requirements were combined in a tube and allowed to grow for several hours,they acquired the ability to grow without the addition of biotin.
C)When two bacterial strains with different nutritional requirements were separated from each other by a selective filter,they did not acquire the ability to grow on agar plates that lacked their required nutrients.
D)Only when enough pressure was applied to force bacteria from one side of a selective filter to another did they acquire the ability to grow without their required nutrients.
E)Nutritional deficient strains only acquired the ability to grow without their required nutrients when the pore size of a selective filter was increased to allow bacteria to pass from one side to the other.

Question 5

Prokaryotes

A)include bacteria and archaea
B)include bacteria and viruses
C)are any unicellular organism
D)include bacteria and viruses,but not archaea
E)include bacteria,but not archaea and viruses

Question 6

The different strains of a bacterial species

A)may be susceptible to different antibiotics
B)reproduce asexually
C)may be the result of random mutations
D)can participate in conjugation and transformation
E)all of these are correct

Question 7

Bacterial Strain A divides every 30 minutes.If you require at least 4 billion cells to perform an experiment,how many hours will you need to incubate a culture tube inoculated with a single cell of Bacteria A to get enough material to perform your experiment?

A)2
B)16
C)8
D)4
E)32

Question 8

A __________ bacterial cell is able to take up DNA from the environment.

A)competent
B)virulent
C)fertile
D)high frequency
E)transduced

Question 9

Bacterial plasmids

A)are essential for growth
B)can provide genes that allow the bacteria to grow and thrive in the presence of potential toxins
C)are essential for cellular respiration
D)are artificially created by humans and are present in bacteria only because humans put them there
E)are essential for chromosome replication and binary fission

Question 10

Place the following events of bacterial conjugation in order from first to last.
1 - DNA replication
2 - an enzyme joins F factor DNA ends
3 - sex pilus shortens
4 - DNA transfer
5 - an enzyme cuts F factor DNA

A)1,2,3,4,5
B)3,5,4,2,1
C)5,1,3,4,2
D)3,5,1,4,2
E)3,5,1,2,4

Question 11

A bacterial cell must have ___________ in order to transfer portions of its chromosome to another cell.

A)an F factor
B)a virulence plasmid
C)competence factors
D)growth enhancement genes
E)all of these components

Question 12

How is binary fission similar to the mitosis/cytokinesis?

A)both are modes of sexual reproduction
B)both occur only in eukaryotes
C)both occur only in prokaryotes
D)both involve replication of DNA and separation of DNA equally into two daughter cells
E)both give rise to offspring that are genetically different from the parent

Question 13

In conjugation,the donor cell makes ___________ whose function is to bring F- cells close enough to transfer a ___________ to the recipient.

A)a sex pilus,single strand of DNA
B)a sex pilus,double strand of DNA
C)an F factor,fertility plasmid
D)an F factor,replicated F factor
E)a sex pilus,bacterial chromosome

Question 14

You discover a bacteria species in a deep ocean sample that can turn olive oil into pure gold.The bacteria do not replicate well at sea level,and one night all of your "Golden" bacteria die.What can you do to possibly retrieve the gold-making gene from the dead Golden bacteria?

A)transform a live bacterial strain with the Golden bacteria's DNA
B)transduce a live bacterial strain with the Golden bacteria's DNA
C)conjugate a live bacterial strain with the Golden bacteria
D)transduce the Golden bacteria and then infect a live strain of bacteria with the transducing virus
E)there is nothing you can do because the cells are dead.You will have to search the ocean and hope to find the elusive bacteria again

Question 15

The prokaryotic chromosome is

A)held within a membrane-bound nucleus
B)localized to a nucleoid region
C)circular and loosely packed
D)composed of single-stranded DNA
E)linear and tightly wrapped around histone proteins

Question 16

You analyze two daughter cells of Bacteria A immediately after binary fission.Which of the following is ACCURATE about the daughter cells?

A)Each will have about half the number of plasmids as the mother cell.
B)They are members of the same colony.
C)They have genetically identical chromosomes.
D)They are members of the same colony and have genetically identical chromosomes.
E)They are members of the same colony,will have genetically identical chromosomes,and each will have about half the number of plasmids as the mother cell.

Question 17

An episome is

A)a plasmid that can make bacterial cells resistant to antibiotics
B)a plasmid that gives bacteria the ability to degrade toluene
C)a plasmid that can exist either autonomously in the cytoplasm or as part of a chromosome
D)a plasmid that can turn a bacteria that is harmless into a strain that can cause disease
E)a plasmid that gives bacteria the ability to exchange DNA with another bacterial cell

Question 18

Which of the following is NOT a characteristic of bacterial chromosomes?

A)they are single stranded
B)they are around 10* smaller than eukaryotic chromosomes
C)they contain gene coding regions and regulatory regions
D)they can be present in more than one copy
E)they have only one origin of replication

Question 19

What mechanism is used by a bacterial cell to fit its DNA into the nucleoid region?

A)the formation of loop domains
B)supercoiling by topoisomerases
C)tight wrapping around histones to form nucleosomes
D)the formation of loop domains and supercoiling by topoisomerases
E)the formation of loop domains,supercoiling by topoisomerases,and tight wrapping around histones to form nucleosomes

Question 20

A mutation in the gene encoding the enzyme that cuts F factor DNA during conjugation would result in

A)an inability to separate the recipient DNA from the donor DNA
B)an inability to draw the conjugated cells close enough to allow DNA transfer
C)the transfer of single-stranded DNA instead of double-stranded DNA
D)the inability of the donor DNA to move through the pilus
E)the inability of the recipient cell to replicate the F factor after transfer

Question 21

Which of the following is not a part of the general viral reproductive cycle?

A)viral recognition of host surface proteins
B)genome entry into the cell and immediate expression of some viral genes
C)viral proteins are synthesized
D)reverse transcriptase converts RNA to DNA
E)fully assembled viruses are released

Question 22

The influenza virus is typical of many animal viruses in that is has an envelope composed of lipids and glycoproteins.Which of the following statements about the envelope is ACCURATE?

A)the envelope glycoproteins are encoded by genes found in the host genome
B)the envelope is inside the capsid
C)the envelope is obtained from the host cell when the virus buds from the plasma membrane
D)the envelope is obtained from the host cell upon entry into the cell
E)the envelope is formed via the action of integrase

Question 23

Which of the following components of a virus is not encoded by its own genome?

A)capsid
B)lipid bilayer of viral envelope
C)spike glycoproteins of viral envelope
D)bacteriophage anchoring structures
E)tail fibers

Question 24

Persons infected with HIV often die of opportunistic diseases because

A)HIV can transduce other viruses into virulent strains
B)HIV destroys T cells
C)HIV binds to antibodies
D)HIV is a retrovirus
E)HIV mutates easily

Question 25

Soon after the introduction of antibiotics,resistant strains of bacteria that could grow in the presence of particular antibiotics began to evolve.Researchers develop new antibiotics,only to see resistant bacterial strains evolve within a few years.Which of the following explains why resistant strains of bacteria can evolve so quickly?

A)bacteria have a short generation time
B)bacteria can transfer plasmids containing resistance genes via conjugation
C)horizontal gene transfer
D)bacteria have a short generation time and can transfer plasmids containing resistance genes via conjugation
E)bacteria have a short generation time and can transfer plasmids containing resistance genes by horizontal gene transfer mechanisms such as conjugation

Question 26

Bacterial infections have become much more of a threat to human health due to which of the following?

A)the increased use of antibiotics
B)an increase in acquired antibiotic resistance by innocuous strains
C)horizontal transfer of pathogenicity
D)an increased use of antibiotics coupled with an increase in acquired antibiotic resistance by innocuous strains
E)an increased use of antibiotics,horizontal transfer of pathogenicity,and an increase in acquired antibiotic resistance by innocuous strains

Question 27

A scientist has been growing a bacterial strain for some time in culture media containing very few nutrients.The cells are growing slowly,so she enriches the media with amino acids and carbohydrates.To her dismay,instead of growing faster and to higher densities,the bacteria begin to die.What has caused this strange result?

A)a prophage switched from the lysogenic cycle to the lytic cyle
B)a prophage switched from the lytic cycle to the lysogenic cycle
C)the bacteria are infected with a temperate phage
D)the bacteria are infected with a virulent phage that has switched from the lysogenic cycle to the lytic cycle
E)the bacteria are infected with a temperate phage that has switched from the lysogenic cycle to the lytic cycle

Question 28

Viral release from a bacterial cell

A)requires the production of lysozyme encoded by the viral genome
B)requires the production of lysozyme encoded by the eukaryotic genome
C)kills the infected cell
D)requires the production of lysozyme encoded by the viral genome and kills the infected cell
E)requires the production of lysozyme encoded by the eukaryotic genome and kills the bacterial cell

Question 29

Which of the following characteristics do all viruses have in common?

A)they are all incapable of replicating their own nucleic acid
B)they all have DNA genomes
C)they all have a broad host range
D)they all infect eukaryotes
E)they all contain a capsid surrounded by a fatty envelope

Question 30

Dmitri Ivanovski demonstrated that TMV was not spread via bacteria by

A)transmitting sap of infected plants from generation to generation
B)filtering sap from an infected plant through pores smaller than bacteria,and then applying it to a healthy plant
C)spraying sap from an infected plant onto a healthy plant
D)sterilizing sap from an infected plant and then applying it to a healthy plant
E)treating an infected plant with a broad spectrum of antibiotics before extracting sap

Question 31

A particle that consists of nucleic acids surrounded by protein and requires a host organism to replicate is

A)a prokaryote
B)a eukaryote
C)a plasmid
D)a virus
E)bacterium

Question 32

Which of the following is an emerging virus?

A)HIV
B)Tobacco mosaic virus
C)Escherishia coli
D)Lamda phage
E)All of these choices are emerging viruses

Question 33

Integrase

A)is required for prophage formation
B)cuts viral genomes
C)is required for genome entry into the bacteria
D)is required for provirus formation
E)cuts the viral genome and is required for both prophage and provirus formation

Question 34

How do the reproduction of human immunodeficiency virus (HIV)and bacteriophage lambda differ from each other?

A)HIV enocodes and uses reverse transcriptase,while lambda phage does not
B)HIV production requires integrase,while bacteriophage lambda does not
C)HIV can reproduce in either eukaryotic or prokaryotic cells,while bacteriophage lambda can only infect bacteria
D)bacteriophage lambda attaches to specific proteins on the cell surface,while HIV does not
E)None of these is correct

Question 35

Transduction is the result of what "mistake" that viruses make during replication?

A)cutting up the bacterial chromosome
B)cutting up the viral genome
C)transcribing bacterial genes upon excision
D)incorporating bacterial genes during assembly
E)inserting a viral DNA fragment into the bacterial chromosome

Question 36

When a virus has a broad host range

A)it does not require close contact to infect a new host
B)it can infect many different cell types
C)it can infect many different species
D)the species that the virus can infect are spread over a large geographic distance,potentially causing pandemics
E)it can infect many cell types or species

Question 37

A pro- strain of bacteria,which has not been in contact with any other strains,develops the ability to produce the amino acid proline.What is the most likely mechanism of this mutant "rescue?"

A)addition of the pro+ gene via transduction
B)addition of the pro+ gene during conjugation
C)removal of the pro- gene during excision
D)addition of the pro+ gene via transformation
E)correction of the pro- gene by reverse transcriptase

Question 38

While a prophage genome is integrated into the host cell chromosome,it is

A)latent
B)lysogenic
C)virulent
D)latent and lysogenic
E)latent,lysogenic,and virulent

Question 39

Baculovirus genomes are 133.9 kb long and encode over 150 genes.This suggests that

A)their protein structures are very complex
B)their protein coats consist of very few types of protein subunits
C)their genetic material is RNA
D)their genetic material is DNA
E)they have a small host range

Question 40

Transduction is

A)the transfer of viral genes to a bacteria by a virus
B)the transfer of bacterial genes to another bacteria by a virus
C)the use of bacterial replication machinery to produce viral particles
D)the transfer of bacterial genes from one bacteria to another
E)the transfer of bacterial genes to another via a pilus

Question 41

To fit into the nucleiod region,a bacterial chromosome is tightly wrapped around histone proteins.

Question 42

The transfer of genes from dead bacteria to live bacteria is called transformation.

Question 43

Plasmids can help bacteria grow faster.

Question 44

Bacterial conjugation is also called bacterial sex because there is an equal exchange of genetic information between two cells.

Question 45

It has been difficult to create an effective vaccine against HIV because reverse transcriptase cannot correct its errors.

Question 46

Drugs that are HIV protease inhibitors

A)prevent HIV protease from degrading host cell proteins
B)block the translation of HIV proteases
C)bind to HIV proteases
D)prevent HIV proteases from breaking apart capsid proteins
E)bind to HIV proteases and prevent the proteases from breaking apart capsid proteins

Question 47

Viral genomes must always be excised from the bacterial chromosome before viral components can be produced.

Question 48

Lederberg and Tatum's landmark experiment showed that gene transfer could occur between bacteria,by mixing two strains of bacteria.One strain of bacteria could not synthesize methionine or biotin,but was capable of synthesizing threonine and proline.The other strain was able to synthesize methionine and biotin,but was not capable of synthesizing threonine and proline.Only when these strains were mixed together would they grow on agar that lacked these compounds.What positive control would Lederberg and Tatum have used to ensure that their experiments were accurate?

A)A bacteria that was not cable of synthesizing methionine,biotin,threonin or proline.
B)A bacteria that was capable of synthesizing methionine,biotin,threonin and proline.
C)An agar medium that contained methionine,biotin,threonin and proline.
D)An agar medium that lacked methionine,biotin,threonin,proline,and other nutrients that all bacteria require to grow (e.g.glucose).
E)No positive control would be used in this experiment because there are already two different strains of bacteria being tested.

Question 49

A person is infected with HIV.The individual is treated with several drugs,including azidothymidine (AZT).AZT competes for the active site of reverse transcriptase.Which of the following is the most immediate effect of this drug?

A)it allows reverse transcriptase to proofread,and this will allow successful treatment with a vaccine
B)it does not allow the virus to make a DNA copy of its genome
C)it does not allow the viral genome to become integrated into the host genome
D)it inhibits formation of the capsid
E)it inhibits budding,as it is the reverse of the process by which HIV enters a cell

Question 50

Bacterial cells always contain one copy of a circular chromosome.

Question 51

Viruses infect only eukaryotes.

Question 52

All forms of horizontal gene transfer require both the recipient and donor bacteria to be alive.

Question 53

You are reconstructing a phylogeny (evolutionary tree)of three strains of the same bacteria species.Analysis of different genes results in different phylogenies.Phylogeny A analyzed the bacterial strains using the smil gene,while phylogeny B analyzed the nosy gene.The true evolution of these strains is illustrated below the phylogenies.Study these diagrams and determine what is the best representation of these bacterial strains and why.

A)Phylogeny A,because the nosy gene was acquired via horizontal gene transfer and not an ancestor-descent relationship.
B)Phylogeny A,because the smil gene was acquired via horizontal gene transfer and not an ancestor-descent relationship.
C)Phylogeny B,because the nosy gene was acquired via horizontal gene transfer and not an ancestor-descent relationship.
D)Phylogeny B,because the smil gene was acquired via horizontal gene transfer and not an ancestor-descent relationship.
E)Phylogeny A and B are equally good representations of the relationships between these bacterial strains.

Question 54

The figure below represents a lineage of a bacterial strain.Study the figure and determine what is the most likely mechanism that induced a change in the phenotype of this lineage.

A)Random mutation
B)Conjugation
C)Transduction
D)Transformation
E)Lysogeny

Question 55

The figure below represents a lineage of a bacterial strain.Upon further studies of this system,you learn that the phage that infects the blue smile bacteria has a very small host range,and cannot infect the red smile bacteria.In light of this new information,determine what is the most likely mechanism that induced a change in the phenotype of this lineage.

A)Random mutation
B)Conjugation
C)Transformation
D)Transduction
E)Lysogeny

Question 56

Bacteria can exchange DNA between strains of the same species and between different species.

Question 57

Plasmids replicate independently of the bacterial chromosome

Question 58

During HIV reproduction,spike glycoproteins

A)do not enter the cell with the virus
B)are released into the cytoplasm by cellular enzymes
C)undergo a conformational change to inject viral contents into the host cell
D)are assembled into the virus along with reverse transcriptase
E)are embedded in the viral capsid

Question 59

Adenoviruses are a frequent cause of acute upper respiratory tract infections in humans.Adenoviruses are non-enveloped and their capsid contains a "fiber" protein that is analogous in function to the spike glycoproteins of HIV.Which of the following would be ACCURATE about an adenovirus that has a mutation in its fiber protein gene?

A)the virus would still cause upper respiratory tract infections in humans but at a slower rate
B)because it has defective fiber proteins,it will now have a broader host range
C)it would not be able to cause disease in humans
D)it would be able to infect humans normally,but would not be able to replicate its genome
E)it would be able to infect humans normally,but would not be able to release new adenoviruses from the human cells

Question 60

Adenoviruses are a frequent cause of acute upper respiratory tract infections in humans.Adenoviruses have a genome composed of double-stranded DNA,they are non-enveloped and their capsid contains a "fiber" protein that is analogous in function to the spike glycoproteins of HIV.Latency of the adenovirus can occur in lymphoid tissues.Based on this information,which of the following would be the best type of drug to develop to combat adenoviruses in humans?

A)a drug that inhibits reverse transcriptase
B)a drug that binds to fiber protein receptors in human cells
C)a drug that can switch off latency
D)a combination of drugs that inhibit reverse transcriptase and that binds to fiber protein receptors in human cells
E)a combination of drugs that inhibit reverse transcriptase,binds to fiber protein receptors in human cells,and switches off latency

Question 61

Lederberg and Tatum's landmark experiment showed that gene transfer could occur between bacteria,by mixing two strains of bacteria.One strain of bacteria could not synthesize methionine or biotin,but was capable of synthesizing threonine and proline.The other strain was able to synthesize methionine and biotin,but was not capable of synthesizing threonine and proline.Only when these strains were mixed together would they grow on agar that lacked these compounds.What negative control would Lederberg and Tatum have used to ensure that their experiments were accurate?

A)A bacteria that could synthesize methionine,biotin,threonine,and proline.
B)A bacteria that could not synthesize methionine,biotin,threonine,or proline.
C)An agar media that contained methionine,biotin,threonine,and proline.
D)An agar medium that lacked methionine,biotin,threonin,proline,and other nutrients that all bacteria require to grow (e.g.glucose).
E)A plate that contained no bacteria