Deck 13: Viruses, Viroids, and Prions

Question 1

During attachment of phage to E. coli, the phage

A) actively seeks out the bacteria AND attaches to proteins or carbohydrates on the bacterial surface.
B) randomly bumps into the bacteria AND attaches to proteins or carbohydrates on the bacterial surface.
C) randomly bumps into the bacteria AND attaches to the bacterial RNA.
D) randomly bumps into the bacteria AND attaches to the bacterial DNA.
E) actively seeks out the bacteria AND attaches to the bacterial DNA.

Answer 1

B

Question 2

The shape of the virus is determined by its

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

Answer 2

B

Question 3

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.

Answer 3

D

Question 4

Phage-encoded enzymes are

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

Question 5

Viruses that infect bacteria are referred to as

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

Question 6

A virion is a(n)

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

Question 7

What part of the E. coli T4 phage attaches to the host cell receptors?

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) Spikes of the cell wall.

Question 8

Outside of living cells, viruses are

A) scavenging glucose.
B) gaining ATP from the mitochondria.
C) metabolically inert.
D) using cilia to move to the next host.
E) replicating by binary fission.

Question 9

A virion is composed of

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

Question 10

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.
E) temperate phage.

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

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

A) temperate phages.
B) lytic phages.
C) virulent phages.
D) segmented phages.
E) bacteriophages.

Question 13

Which of the following BEST describes the protein coat of a virus? It

A) is called a capsomere, AND is involved in the recognition of host cell receptors by non-enveloped viruses.
B) is called a capsid, AND is involved in the recognition of host cell receptors by non-enveloped viruses.
C) protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses.
D) is called a capsomere, protects the nucleic acid, AND 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 14

The viral envelope closely resembles the

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

Question 15

One of the most intensively studied virulent phages which infects E. coli is ________.

A) T9
B) T4
C) beta
D) gamma
E) lambda

Question 16

Which does not refer to the shape of a virus?

A) Bacillus
B) Icosahedral
C) Helical
D) Complex
E) These are all virus shapes.

Question 17

Assembly of the T4 phage

A) is completely self-assembly 
B) is completely dependent on scaffolds.
C) may involve some self-assembly AND may involve the use of scaffolds.
D) may involve some self-assembly AND is completely dependent on scaffolds.
E) is completely self-assembly AND is never dependent on scaffolds.

Question 18

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.
E) attachment, replication of nucleic acid and protein, assembly, penetration, transcription, release.

Question 19

During penetration of E. coli by the T4 phage,

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) the intact phage enters the host by endocytosis.

Question 20

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 21

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.
E) viral DNA has replaced critical bacterial DNA in the phage.

Question 22

Which is True of lysogenized cells?

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

Question 23

The replicative form of nucleic acid in filamentous phages is

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

Question 24

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) lysogenic conversion.
D) prion protein.
E) phase variation.

Question 25

Filamentous phages

A) only infect E. coli that have pili.
B) only infect E. coli lacking pili.
C) infect E. coli regardless of the presence of pili.
D) do not infect E. coli.
E) only infect Gram-negative E. coli.

Question 26

Which statement about most phages that contain single-stranded DNA is NOT True?

A) They are extruded from the host cell.
B) They contain a negative-sense DNA strand.
C) Their DNA is transformed to dsDNA before replication and transcription occur.
D) All of the choices are correct.
E) None of the choices is correct.

Question 27

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

A) 1 per host cell.
B) 5 per host cell.
C) 20 per host cell.
D) 200 per host cell.
E) 1,000 per host cell.

Question 28

The filamentous phages all contain

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

Question 29

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) may be lytic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.
E) may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.

Question 30

Which statement regarding phage replication is True?

A) A lysogen is a bacterial cell with an integrated prophage.
B) When integrated into host DNA, phage DNA is called a virophage.
C) Lambda is a good example of a lytic phage.
D) Lambda can be a lytic or a temperate phage.
E) A lysogen is a virus that has bacterial DNA in it.

Question 31

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.
E) a phage-encoded RNA polymerase is used to make DNA using the phage positive-sense RNA as a template.

Question 32

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

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

Question 33

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.
E) bacterial repressor genes are deactivated.

Question 34

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.
E) helical phages.

Question 35

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 that allow it to enter the bacterium.
C) similarity in RNA nucleotides in both the phage and the bacterial host.
D) the similarity in enzyme metabolism in the phage and the bacterial cell.
E) the phage's ability to synthesize enzymes to enter the bacterium AND similar RNA nucleotides in both.

Question 36

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

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

Question 37

Which is a filamentous phage?

A) M13
B) T4
C) Lambda
D) TMV
E) T2

Question 38

A limiting factor for viral infection of animals cells is

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

Question 39

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

A) 1 day.
B) 30 minutes.
C) 10 minutes.
D) 1 minute.
E) 45 seconds.

Question 40

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

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

Question 41

Enveloped viruses

A) never use spikes for attachment to host cells.
B) have a lipid bilayer membrane containing various proteins.
C) are surrounded by an additional layer of carbohydrate.
D) surround the boundary of a host cell.
E) are difficult to destroy using detergents.

Question 42

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

Question 43

Transduction often involves defective virus.

Question 44

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 and cannot survive.
D) A virus that cannot attach to its host cell and therefore cannot enter the target cell.
E) A virus that lacks a prophage, cannot enter a host cell, and cannot survive.

Question 45

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 in pathogens.
C) lysed bacteria pose no threat to a person's health.
D) a single phage can be genetically engineered to infect many different species of bacteria.
E) of the increasing problem of antibiotic resistance in people.

Question 46

A filamentous phage is incapable of causing a lytic infection.

Question 47

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

Question 48

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

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

Question 49

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.
E) DNA or RNA, lipid, and protein.

Question 50

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

Question 51

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

A) 2
B) 5
C) 7
D) 13
E) 6

Question 52

Once inside the host cell, phage DNA

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

Question 53

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

Question 54

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

A) 7
B) 5
C) 4
D) 2
E) 6

Question 55

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.
E) types of bacteriophages.

Question 56

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 that has several components.
E) may contain RNA with undefined regions in it.

Question 57

Viruses are commonly referred to by their ________ name.

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

Question 58

What are two ways that phage can replicate without directly lysing their host cell?

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

Question 59

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

Question 60

All of the statements about specialized transduction are correct EXCEPT

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

Question 61

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.
E) the viruses release lysozyme which destroys the host cell wall.

Question 62

Resistance of some animals to certain viral diseases is based on

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

Question 63

A key feature of all viral infections is the

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

Question 64

The best known chronic infection involves

A) hepatitis B.
B) hepatitis A.
C) chickenpox.
D) herpes.
E) influenza.

Question 65

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

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

Question 66

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

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

Question 67

Entry of bacteriophages and animal viruses into host cells

A) is by endocytosis.
B) is by fusion.
C) involve entry of the entire nucleocapsid.
D) differs because bacteriophages leave the capsid outside the cell, while animal virus entry involves the entry of the whole nucleocapsid.
E) differs because animal viruses leave the capsid outside the cell, while bacteriophage entry involves the entry of the whole nucleocapsid.

Question 68

The family to which the Rhinovirus belongs is the

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

Question 69

In the region of budding, the cytoplasmic membrane acquires

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

Question 70

Carriers

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

Question 71

The common species name of the virus is frequently 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.
E) shape of the viral nucleocapsid.

Question 72

The receptors to which animal virus attachment proteins usually bind are

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

Question 73

In latent infections, the virions are

A) constantly produced.
B) only produced during reactivation.
C) produced very slowly.
D) continually being slowly budded out.
E) always detectable in the infected person.

Question 74

The genome of retroviruses is made of

A) ssDNA.
B) dsDNA.
C) ssRNA.
D) dsRNA.
E) protein and RNA.

Question 75

The best-known examples of viruses that cause latent infections are

A) polio AND herpes.
B) herpes AND measles.
C) measles AND chickenpox.
D) chickenpox AND polio.
E) herpes AND chickenpox.

Question 76

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

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

Question 77

When a non-enveloped animal 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) endocytosis.
D) fusion.
E) budding.

Question 78

The enveloped viruses typically obtain their envelope

A) from the host cytoplasmic membrane as they exit the host.
B) from a newly constructed viral-derived membrane.
C) from the nuclear membrane as they exit the host.
D) from endoplasmic reticulum in the host.
E) from the host peptidoglycan as they exit.

Question 79

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

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

Question 80

For which of the following processes are enzymes not required?

A) Replication
B) Self-assembly
C) Translation
D) Maturation
E) All of the answer choices are correct.