Deck 13: Viruses, Viroids, and Prions

Question 1

During penetration of

A)lysozyme is used to allow entry of the phage capsid.
B)the tail acts as a "hypodermic needle," injecting the phage DNA into the cell.
C)the protein fibers digest a hole in the cell wall.
D)the bacterial receptor molecules open a hole through the cell wall.
E)coli by the T4 phage

Answer 1

the tail acts as a "hypodermic needle," injecting the phage DNA into the cell.

Question 2

The term filterable viruses was coined by

A)Beijerinck.
B)Iwanowsky.
C)Twort.
D)d'Herelle.

Answer 2

Beijerinck.

Question 3

Which does not refer to the shape of a virus?

A)Icosahedral (isometric)
B)Helical
C)Complex
D)Bacillus

Answer 3

Bacillus

Question 4

A virion is a(n)

A)pathogenic virus.
B)subviral particle.
C)complete,extracellular virus particle.
D)enveloped virus particle.

Question 5

Phages that can either replicate and cause cell lysis or can integrate their DNA into the host DNA are called

A)lysogenic phages.
B)lytic phages.
C)virulent phages.
D)segmented phages.

Question 6

The viral envelope closely resembles the

A)prokaryotic cell wall.
B)capsomere.
C)eukaryotic cellular membrane.
D)cytoplasm.

Question 7

A phage that replicates inside the host cell and then lyses its host during its release is a

A)virulent or lytic phage.
B)latent phage.
C)lysogenic phage.
D)dormant phage.

Question 8

The protein projections on the surface of a virus that are involved in attachment to the host cell are called

A)suckers.
B)pili.
C)cilia.
D)spikes.
E)hooks.

Question 9

The shape of the virus is determined by its

A)nucleic acid.
B)capsid.
C)envelope.
D)tail.

Question 10

One of the most intensively studied virulent phages which infects

A)T9.
B)T4.
C)beta.
D)gamma.
E)coli is

Question 11

What part of the attached bacteriophage enters through the host cell wall?

A)The entire virus
B)Only the enzymes necessary for replication
C)The nucleic acid
D)The nucleic acid and capsid
E)The capsid only

Question 12

Viruses

A)probably keep the numbers of bacteria in check.
B)have no effect on the number of bacteria.
C)increase the number of bacteria.
D)are active in passing DNA from one bacterium to another.
E)probably keep the numbers of bacteria in check AND are active in passing DNA from one bacterium to another.

Question 13

Outside of living cells,viruses are

A)scavenging glucose.
B)slowly stockpiling ATP from the mitochondria.
C)using cilia to move to the next host.
D)metabolically inert.

Question 14

The protein coat of a virus

A)is called a capsomere.
B)is called a capsid.
C)protects the nucleic acid.
D)is involved in the recognition of host cell receptors by non-enveloped viruses.
E)is called a capsid,protects the nucleic acid,AND is involved in the recognition of host cell receptors by non-enveloped viruses.

Question 15

The correct order for the stages of a phage infection is:

A)penetration,transcription,attachment,replication of nucleic acid and protein,assembly,release.
B)attachment,penetration,transcription,replication of nucleic acid and protein,assembly,release.
C)attachment,replication of nucleic acid and protein,penetration,transcription,assembly,release.
D)transcription,attachment replication of nucleic acid and protein,assembly,penetration,release.

Question 16

Phage-encoded proteins are

A)coded for by host DNA.
B)coded for by phage DNA.
C)proteins normally present in the uninfected cell.
D)early proteins.
E)coded for by phage DNA AND early proteins.

Question 17

What part of the

A)Capsid fragments around the nucleic acid
B)Protein fibers at the end of the phage tail
C)Pili of the envelope
D)Spikes of the envelope
E)coli T4 phage attaches to the host cell receptors?

Question 18

A virion is composed of

A)lipid,protein,and either RNA or DNA.
B)protein and either RNA or DNA,but no lipid.
C)protein and both RNA and DNA,but no lipid.
D)protein,either RNA or DNA,and possibly lipid.

Question 19

Crystallization of tobacco mosaic virus was accomplished by

A)Berkley.
B)Stanley.
C)Iwanowsky.
D)Twort.

Question 20

Viruses that infect bacteria are referred to as

A)viralcidens.
B)bacteriocidins.
C)bacterialogens.
D)bacteriophages.

Question 21

In the replication of phage containing positive-sense DNA,

A)the host's enzymes are used to make dsDNA.
B)the host's DNA polymerase uses the phage RNA as a template to make negative-sense DNA.
C)a phage-encoded DNA polymerase is used to make negative-sense RNA using the phage positive-sense RNA as a template.
D)a phage-encoded DNA polymerase is used to make DNA using the phage positive-sense RNA as a template.

Question 22

The filamentous phages all contain

A)single-stranded DNA.
B)double-stranded DNA.
C)single-stranded RNA.
D)double-stranded RNA.

Question 23

In the case of T-even phages,the burst size is about

A)1 per host cell.
B)5 per host cell.
C)200 per host cell.
D)1,000 per host cell.

Question 24

The integration of phage DNA into the bacterial chromosome occurs because of

A)the phage's ability to synthesize an enzyme that integrates its DNA into the host's chromosome.
B)the phage's ability to synthesize enzymes to enter the bacterium.
C)similar RNA nucleotides in both.
D)the similarity in enzyme metabolism.
E)the phage's ability to synthesize enzymes to enter the bacterium AND similar RNA nucleotides in both.

Question 25

Lysogenized cells

A)are immune to any further infection by any virus.
B)are immune to infection by the same virus.
C)may have new properties.
D)respond to infection with the SOS response.
E)are immune to infection by the same virus AND may have new properties.

Question 26

Assembly of the T4 phage

A)may involve some self-assembly.
B)may involve the use of scaffolds.
C)is completely self-assembly.
D)is completely dependent on scaffolds.
E)may involve some self-assembly AND may involve the use of scaffolds.

Question 27

An exit method used by viruses that does not immediately destroy the host bacterium is

A)lysis.
B)inversion.
C)extrusion.
D)excising.

Question 28

Phage-encoded enzymes are

A)all produced simultaneously.
B)produced in a sequential manner.
C)strictly host enzymes.
D)used to customize the cell for viral production.
E)produced in a sequential manner AND used to customize the cell for viral production.

Question 29

The replicative form of nucleic acid in filamentous phages is

A)dsDNA.
B)dsRNA.
C)positive ssRNA.
D)negative ssDNA.

Question 30

DNA is protected from restriction enzymes by being

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

Question 31

The phenomenon responsible for the ability of Corynebacterium diphtherium to produce the virulent toxin responsible for the devastating effects of diphtheria is called

A)self-assembly.
B)matrix conversion.
C)prion protein.
D)lysogenic conversion.

Question 32

Most phages that contain single-stranded DNA

A)are extruded.
B)contain a positive-sense DNA strand.
C)have their DNA transformed to double-stranded DNA before replication and transcription occur.
D)All of the choices are correct.

Question 33

The time from absorption to release for T-even phage is about

A)1 minute.
B)10 minutes.
C)30 minutes.
D)1 day.

Question 34

Regarding phage replication,

A)the majority of phages are temperate.
B)when integrated into host DNA,the phage DNA is called a prophage.
C)lambda is a good example of a temperate phage.
D)All of the choices are correct.

Question 35

The activation of the SOS system in a bacterium infected with a prophage results in

A)destruction of the viral genes.
B)complete lysis of the bacterial culture.
C)mutation of the DNA.
D)destruction of the viral repressor through host protease activity.
E)complete lysis of the bacterial culture AND destruction of the viral repressor through host protease activity.

Question 36

Transducing virulent phages do not lyse the cells they invade because

A)transformation is taking place in the phage and this is transferred to the bacterium.
B)bacterial DNA has replaced critical viral DNA in the phage.
C)their virulence is dependent on the bacteria and virus replicating together.
D)the lytic genes are unable to enter during penetration and are shed outside the host.

Question 37

A temperate phage

A)may be lysogenic.
B)may be lytic.
C)enters a lysogenic or lytic life cycle shortly after entering the host cell.
D)are all RNA viruses.
E)may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.

Question 38

The bacterial viruses that are released by a process termed extrusion are called

A)lysogenic viruses.
B)temperate phages.
C)filamentous phages.
D)lambda viruses.

Question 39

Once integrated,phage DNA can remain in the prophage state as long as

A)the bacteria is frequently plated on new media.
B)certain phage genes are excised.
C)certain phage genes are repressed.
D)bacterial repressor genes are activated.

Question 40

Which is a filamentous phage?

A)M13.
B)T4.
C)Lambda.
D)TMV.

Question 41

Using phages to treat a bacterial infection is an interesting idea because

A)a single type of phage can destroy a wide range of strains of the same pathogen.
B)of the increasing problem of antibiotic resistance.
C)lysed bacteria pose no threat.
D)a single phage can be genetically engineered to infect many different species of bacteria.

Question 42

A lysogenic cell contains viral DNA,a prophage,integrated into the host chromosome.

Question 43

Animal viruses are divided into a number of families whose names end in

A)-virus.
B)-viridae.
C)-viscous.
D)-eieio.

Question 44

The term "segmented" refers to viruses that

A)may contain several pieces of RNA.
B)have an icosahedral-shaped capsid.
C)are linked together before budding out.
D)have an envelope.

Question 45

The integration of phage DNA into host DNA occurs in much the same fashion as seen in transformation,transduction,or conjugation.

Question 46

What are two ways that phage can replicate in harmony (not directly lysing)their host cell?

A)Conjugation and lysogeny
B)Lysogeny and transduction
C)Extrusion and transformation
D)Extrusion and lysogeny

Question 47

Enveloped viruses

A)just require a stamp.
B)have an outer lipid bilayer membrane containing various proteins.
C)are surrounded by an additional layer of carbohydrate.
D)envelope a cell.

Question 48

Virulent as well as temperate phages can serve as generalized transducing phages.

Question 49

If the infecting phage lacks some critical pieces of DNA necessary for replication,it is called

A)incomplete.
B)mutated.
C)defective.
D)vegetative.

Question 50

Completed filamentous phages are often found in the cytoplasm of infected bacteria.

Question 51

The host range of a virus depends on the presence of host receptor molecules.

Question 52

Transduction often involves defective virus.

Question 53

Once inside the host cell,phage DNA

A)is replicated.
B)is transcribed.
C)may get degraded by bacterial nucleases.
D)All of the choices are correct.

Question 54

The terms helical,icosahedral,and complex refer to

A)viral life cycles.
B)forms of nucleic acid.
C)types of viral envelopes.
D)shapes of viruses.

Question 55

Specialized transduction

A)involves the random transmission of any gene.
B)involves the transfer of a few specific genes.
C)utilizes a defective virus.
D)only involves genes near the viral DNA integration site.
E)involves the transfer of a few specific genes,utilizes a defective virus AND only involves genes near the viral DNA integration site.

Question 56

Filamentous virus is incapable of causing a lytic infection.

Question 57

What is a defective phage?

A)A virus that has lost some of its genetic material,and therefore cannot infect a new target cell
B)A virus that has lost some of its genetic material,and therefore cannot replicate within a new target cell
C)A virus that lacks the ability to replicate independently of its host cell
D)A virus that cannot attach to its host cell

Question 58

The nucleocapsid is composed of

A)DNA and RNA and protein.
B)DNA or RNA and protein.
C)protein located in the nucleus.
D)nucleic acid in the ribosome.

Question 59

The restriction-modification system always has two genes involved,the cutting enzyme and the methylating enzyme.

Question 60

A limiting factor for viral infection is

A)internal metabolic temperature of the host cell.
B)nutrition of the host cell.
C)stage of cell cycle of the host cell.
D)presence of specific receptor molecules on the host cell.

Question 61

Viruses are commonly referred to by their _________ name.

A)locale
B)genus
C)disease
D)species
E)disease AND species

Question 62

In the region of budding,the inside of the plasma membrane becomes coated with

A)enzymes.
B)carbohydrates.
C)steroids.
D)matrix proteins.

Question 63

For which of the following processes are enzymes not required?

A)Replication
B)Translation
C)Maturation
D)Self-assembly

Question 64

There are _______ major families of DNA containing viruses that infect vertebrates.

A)2
B)4
C)5
D)7

Question 65

The family to which the Rhinovirus belongs is the

A)Picornaviridae.
B)Enterovirus.
C)Enteroviridae.
D)Picornavirus.

Question 66

In latent infections,the virions are

A)constantly produced.
B)only produced during reactivation.
C)produced slowly.
D)continually being slowly budded out.

Question 67

Bacteriophages and animal viruses

A)both may enter a host cell by endocytosis.
B)both may enter a host cell by fusion.
C)both involve entry of the entire nucleocapsid.
D)differ because bacteriophages leave the capsid outside the cell,while animal virus entry involves the entry of the whole nucleocapsid.

Question 68

In the region of budding,the plasma membrane acquires

A)carbohydrates.
B)spike proteins.
C)matrix proteins.
D)enzymes.
E)spike proteins AND matrix proteins.

Question 69

Cells infected with animal viruses lyse because

A)the release of the virions depletes the cell of energy.
B)the virus releases enzymes that lyse the cell.
C)functions necessary for cell survival are not carried out and the cell dies.
D)the virus RNA and cellular protein interact to kill the cell.

Question 70

In addition to lysis,animal viruses may exit the host cell by

A)extrusion.
B)budding.
C)fission.
D)fusion.

Question 71

The common species name of the virus is based on the

A)presence or absence of a nuclear membrane.
B)type of nucleic acid it contains.
C)disease the virus causes.
D)geographic area it is found.

Question 72

A key feature of all viral infections is the

A)integration of viral DNA into host DNA.
B)disintegration of host DNA.
C)addition of a lipid membrane to the virus.
D)separation of viral nucleic acid from the capsid.

Question 73

Resistance of some animals to certain viral diseases is based on

A)lack of spikes for attachment.
B)phagocytosis of the virus by the host cell.
C)the presence of the viral envelope.
D)lack of specific receptors on the host cell.

Question 74

The receptors to which animal virus attachment proteins usually bind are

A)proteins.
B)carbohydrates.
C)nucleic acid.
D)lipids.
E)glycoproteins.

Question 75

Attachment of animal viruses to the host cell may be by means of

A)a tail.
B)the envelope.
C)a capsid.
D)spikes.

Question 76

An infection in which the virus is continually present in the body is referred to as

A)acute.
B)balanced.
C)determinant.
D)persistent.

Question 77

There are _______ major families of RNA containing viruses that infect vertebrates.

A)2
B)5
C)7
D)13

Question 78

When an enveloped virus adsorbs to the host cell with its protein spikes,the virions are taken into the cell by the process of

A)penetration.
B)production.
C)fusion.
D)endocytosis.

Question 79

Carriers

A)may have a persistent infection.
B)may be a source of infection.
C)usually show symptoms of the disease.
D)have been cured of the infection.
E)may have a persistent infection AND may be a source of infection.

Question 80

The enveloped viruses typically obtain their envelope

A)from the host plasma membrane.
B)as they exit the host.
C)from a newly constructed viral-derived membrane.
D)from the nuclear membrane.
E)from the host plasma membrane AND as they exit the host.