Deck 5: Viral Structure and Life Cycles

Question 1

Viruses acquire envelopes around their nucleocapsids during

A)replication.
B)assembly.
C)adsorption.
D)release.
E)penetration.

Answer 1

D

Question 2

A(n)_____ is the protein shell around the nucleic acid core of a virus.

A)capsomere
B)capsid
C)spike
D)envelope
E)monolayer

Answer 2

B

Question 3

Who developed a rabies vaccine by separating bacteria from virus using a filter?

A)Leewonhoek
B)Koch
C)Pasteur
D)Cohn
E)Semmelwise

Answer 3

C

Question 4

Helical and icosahedral are terms used to describe the shapes of a virus

A)spike.
B)capsomere.
C)envelope.
D)capsid.
E)core.

Question 5

Virus capsids are made from subunits called

A)envelopes.
B)spikes.
C)capsomeres.
D)prophages.
E)peplomers.

Question 6

Viruses with _____ -sense RNA contain the correct message for translation,while viruses with _____ -sense RNA must first be converted into a correct message.

A)positive,negative
B)negative,positive
C)primary,secondary
D)secondary,primary
E)None of the choices is correct.

Question 7

Viruses have all the following except

A)definite shape.
B)metabolism.
C)genes.
D)the ability to infect host cells.
E)ultramicroscopic size.

Question 8

All of the following pertain to virus envelopes except

A)gained as a virus leaves the host cell membrane.
B)are comprised primarily of lipids.
C)contain special virus proteins.
D)help the virus particle attach to host cells.
E)are located between the capsid and nucleic acid.

Question 9

Viruses

A)cannot be seen in a light microscope.
B)are prokaryotic.
C)contain 70S ribosomes.
D)undergo binary fission.
E)All of the choices are correct.

Question 10

The core of every virus particle always contains

A)DNA.
B)capsomeres.
C)enzymes.
D)DNA and RNA.
E)either DNA or RNA.

Question 11

Which of the following is not a typical capsid shape?

A)tetrahedral
B)complex
C)helical
D)icosahedron
E)All of the choices are capsid shapes.

Question 12

A negative-sense RNA virus

A)is ready for immediate translation.
B)must synthesize a negative RNA copy of its genome.
C)must synthesize a positive RNA copy of its genome.
D)is a special form of tRNA used by viruses.
E)always codes for RNA polymerase.

Question 13

Viral nucleic acids include which of the following?

A)double-stranded DNA
B)single-stranded DNA
C)double-stranded RNA
D)single-stranded RNA
E)All of the choices are correct.

Question 14

Which of the following is not associated with every virus?

A)envelope
B)capsomeres
C)capsid
D)nucleic acid
E)genome

Question 15

Host cells of viruses include

A)humans and other animals.
B)plants and fungi.
C)bacteria.
D)protozoa and algae.
E)All of the choices are correct.

Question 16

In general,most DNA viruses multiply in the host cell's _____,while most RNA viruses multiply in the host cell's _____.

A)nucleus,cytoplasm
B)cytoplasm,cell membrane
C)cell membrane,cytoplasm
D)cytoplasm,nucleus
E)nucleus,endoplasmic reticulum

Question 17

A naked virus only has a(n)

A)capsid.
B)capsomere.
C)nucleocapsid.
D)envelope.
E)antigenic surface.

Question 18

Viral spikes

A)are always present on enveloped viruses.
B)protrude from the envelope.
C)block attachment between virus and host.
D)are derived from host proteins.
E)All of the choices are correct.

Question 19

Reverse transcriptase synthesizes

A)the positive RNA strand from a negative RNA strand.
B)a negative RNA strand from a positive RNA strand.
C)RNA from DNA.
D)DNA from RNA.
E)None of the choices is correct.

Question 20

One of the principal capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a(n)_____ capsid.

A)spiked
B)complex
C)icosahedral
D)helical
E)buckeyball

Question 21

Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called

A)latent.
B)oncogenic.
C)prions.
D)viroids.
E)delta agents.

Question 22

T-even phages

A)include the poxviruses.
B)infect Escherichia coli cells.
C)enter host cells by engulfment.
D)have helical capsids.
E)All of the choices are correct.

Question 23

Uncoating of viral nucleic acid

A)does not occur in bacteriophage multiplication.
B)involves enzymatic destruction of the capsid.
C)releases viral nucleic acid into the cell.
D)occurs before replication.
E)All of the choices are correct.

Question 24

Which of the following is a type of cytopathic effect?

A)inclusions in the nucleus
B)multinucleated giant cells
C)inclusions in the cytoplasm
D)cells change shape
E)All of the choices are correct.

Question 25

Which of the following occurs during assembly?

A)Nucleocapsid is formed.
B)New viral nucleic acid is formed.
C)Viral spikes insert in host cell membrane.
D)A nucleocapsid is formed and viral spikes insert in host cell membrane.
E)All of the choices occur.

Question 26

The envelope of enveloped viruses is

A)identical to the host plasma membrane.
B)only composed of host endomembrane.
C)always includes spikes.
D)is obtained by viral budding or exocytosis.
E)None of the choices is correct.

Question 27

Viral tissue specificities are called

A)ranges.
B)virions.
C)receptacles.
D)tropisms.
E)uncoating.

Question 28

Which of the following is not a characteristic of a transformed cell?

A)viral nucleic acid integrated into host DNA
B)decreased growth rate
C)alterations in chromosomes
D)changes in cell surface molecules
E)capacity to divide indefinitely

Question 29

What structures are used by bacteriophages to attach to host cell receptors?

A)sheath
B)tail fibers
C)nucleic acid
D)capsid head
E)None of the choices is correct.

Question 30

Which of the following is incorrect about prophages?

A)present when the virus is in lysogeny
B)formed when viral DNA enters the bacterial chromosome
C)replicated with host DNA and passed on to progeny
D)cause lysis of host cells
E)occur when temperate phages enter host cells

Question 31

Host range is limited by

A)type of nucleic acid in the virus.
B)age of the host cell.
C)type of host cell receptors on cell membrane.
D)size of the host cell.
E)All of the choices are correct.

Question 32

The event that occurs in bacteriophage multiplication that does not occur in animal virus replication is

A)adsorption to the host cells.
B)injection of only the viral nucleic acid into the host cell.
C)host cell synthesis of viral enzymes and capsid proteins.
D)assembly of nucleocapsids.
E)replication of viral nucleic acid.

Question 33

The process of dissolving the envelope and capsid to release the viral nucleic acid is

A)adsorption.
B)penetration.
C)uncoating.
D)synthesis.
E)assembly.

Question 34

Viruses that infect bacteria are specifically called

A)viroids.
B)prions.
C)bacteriophages.
D)satellite viruses.
E)All of the choices infect bacteria.

Question 35

Oncoviruses include all the following except

A)hepatitis B virus.
B)measles virus.
C)papillomavirus.
D)HTLV I.
E)Epstein-Barr virus.

Question 36

Lysogeny refers to

A)altering the host range of a virus.
B)latent state of herpes infections.
C)virion exiting host cell.
D)viral genome inserting into bacterial host chromosome.
E)None of the choices is correct.

Question 37

New,nonenveloped virus release occurs by

A)lysis.
B)budding.
C)exocytosis.
D)both lysis and budding.
E)both budding and exocytosis.

Question 38

Mammalian viruses capable of starting tumors are

A)chronic latent viruses.
B)oncoviruses.
C)syncytia.
D)inclusion bodies.
E)cytiopathic.

Question 39

Viruses attach to their hosts via

A)host glycoproteins.
B)host phospholipids.
C)viral phospholipids.
D)viral flagella.
E)All of the choices are correct.

Question 40

Persistent viruses that can reactivate periodically are

A)chronic latent viruses.
B)oncoviruses.
C)syncytia.
D)inclusion bodies.
E)cytopathic.

Question 41

Cells grown in culture form a(n)

A)monolayer.
B)bilayer.
C)aggregate.
D)plaque.
E)None of the choices is correct.

Question 42

During lysogeny,an inactive prophage state occurs when the viral DNA is inserted into the

A)host cytoplasm.
B)host nucleus.
C)host nucleolus.
D)host DNA.
E)host cell membrane.

Question 43

Creutzfeld-Jacob disease is

A)caused by a chronic latent virus.
B)initiated by an oncogenic virus.
C)caused by a viroid.
D)a spongiform encephalopathy of humans.
E)also called "mad cow disease."

Question 44

A fully formed virus that can cause an infection in a host cell is called a virion.

Question 45

Spikes are glycoproteins of the virus capsid.

Question 46

Viruses are ultramicroscopic because they range in size from 2 mm to 450 mm.

Question 47

Two noncellular agents,smaller than viruses,are the infectious proteins called _____ and the infectious RNA strands called _____.

A)prions,capsomeres
B)virions,prions
C)viroids,phages
D)prions,phages
E)prions,viroids

Question 48

Viruses are used to produce vaccines for prevention of certain viral infections.

Question 49

Infectious protein particles are called

A)viroids.
B)phages.
C)prions.
D)oncogenic viruses.
E)spikes.

Question 50

The primary purpose of viral cultivation is

A)to isolate and identify viruses in clinical specimens.
B)to prepare viruses for vaccines.
C)to do detailed research on viral structure,lifestyle,genetics,and effects on host cells.
D)All of the choices are correct.

Question 51

A common method for cultivating viruses in the lab is to use in vitro systems called _____ cultures.

A)embryo
B)cell
C)plaque
D)bacteriophage
E)egg

Question 52

When a virus enters a host cell,the viral genes redirect the genetic and metabolic activities of the host cell.

Question 53

When a bacterium acquires a trait from its temperate phage,it is called

A)transformation.
B)lysogenic conversion.
C)viral persistence.
D)transcription.
E)translation.

Question 54

The activation of a prophage is called

A)activation.
B)lysogeny.
C)transformation.
D)induction.
E)adsorption.

Question 55

Satellite viruses are

A)also called viroids.
B)dependent on other viruses for replication.
C)the cause of spongiform encephalopathies.
D)significant pathogens of plants.
E)All of the choices are correct.

Question 56

The development of antiviral drug therapy is difficult because

A)viruses are obligate intracellular parasites so the host cell can be harmed by the drug.
B)viruses do not have specific replication cycles that can be targeted.
C)viruses do not contain genetic material.
D)their life cycles do not have distinctive stages.

Question 57

Which of the following will not support viral cultivation?

A)live lab animals
B)embryonated bird eggs
C)primary cell cultures
D)continuous cell cultures
E)All of the choices will support viral cultivation.

Question 58

Infectious naked strands of RNA that affect plants are called

A)viroids.
B)phages.
C)prions.
D)oncogenic viruses.
E)spikes.

Question 59

Visible,clear,well-defined patches in a monolayer of virus-infected cells in a culture are called

A)lysogeny.
B)budding.
C)plaques.
D)cytopathic effects.
E)pocks.

Question 60

What type of phage enters an inactive prophage stage?

A)primary
B)secondary
C)temperate
D)temporary
E)transformed

Question 61

RSV disease is caused by the respiratory syncytial virus (RSV).RSV is a(n)

A)DNA virus.
B)RNA virus.
C)prion.
D)bacteriophage.

Question 62

Prophages can be activated into viral replication and enter the lytic cycle.

Question 63

A bacterium acquiring a new trait from a bacteriophage is a phenomenon called

A)the cytopathic effect.
B)lytic conversion.
C)lysogenic conversion.
D)in vitro cultivation.

Question 64

RSV belongs to which virus family?

A)Poxviridae
B)Picornaviridae
C)Filoviridae
D)Reoviridae

Question 65

After the Harters leave for the hospital,you recall the challenges and limitations researching animal viruses such as RSV.Which of the following is not utilized in the cultivation of animal viruses?

A)bacterial cells
B)embryonated chicken eggs
C)cultured animal cells
D)live animals such as mice

Question 66

Viruses differ from cells in that they consist of

A)only DNA.
B)only RNA.
C)both RNA and DNA.
D)either DNA or RNA but not both.

Question 67

The adeno-associated virus (AAV)is a prion.

Question 68

Viruses mutate and some have not been discovered.

Question 69

Mrs.Harter questions which antibiotic will be given to treat her daughter's infection.You inform her that

A)antibiotics target eukaryotic cells and do not work on viruses.
B)antibiotics target bacterial cells and do not work on viruses.
C)her daughter will be tested for antibiotic sensitivity before they are given for treatment.
D)her daughter can be treated with any antibiotic to inactivate the virus causing RSV disease.

Question 70

Viruses are simple,noncellular,and lack mRNA.

Question 71

The bacteriophage multiplication cycle is similar to that of an animal virus with the exception of uncoating.Uncoating does not occur because

A)they utilize specific receptors on the bacterial surface to adsorb.
B)the viral nucleic acid penetrates the host after being injected through a rigid tube inserted through the bacterial cell membrane and wall.
C)the viral nucleic acid enters the host cell through transformation.
D)the virus is engulfed by the cell and enclosed in a vacuole via endocytosis.

Question 72

Viruses are not filterable.

Question 73

Even though it is a bacterium,Clostridium botulinum can be made more pathogenic once infected with a(n)

A)temperate phage.
B)oncogene.
C)plaque.
D)retrovirus.

Question 74

Mr.Hammond inquires how his wife contracted this viral infection,since she has not come in contact with anyone who has shingles.You recall from microbiology that varicella zoster virus can remain in a chronic latent state in a host by

A)integrating into a bacteriophage.
B)turning on oncogenes.
C)attacking T cells.
D)hiding from the immune system within nerve cells.

Question 75

Viruses are the most common cause of acute infections that do not result in hospitalization.

Question 76

Viral spikes are inserted into the host cell membrane before budding or exocytosis.

Question 77

Viruses contain the necessary tools to invade and control a host cell.These tools may consist of a

A)nucleus,nucleic acid strands of DNA and RNA,and enzymes.
B)capsid or envelope,nucleic acid strands of DNA or RNA,and enzymes.
C)nucleus,nucleic acid strands of RNA,capsid,and enzymes.
D)capsid or envelope,nucleic acid strands of DNA,and enzymes.

Question 78

Which of the following best explains how a bacterial prophage can negatively impact human health?

A)Toxins or enzymes are produced by the infected bacterial pathogen that cause pathology in humans.
B)The entry of the prophage causes cessation of protein synthesis in human cells.
C)The lysis of infected human cells results in the release of numerous phage particles.
D)The entry of the prophage shuts down DNA replication in human cells.

Question 79

Viruses are unable to multiply outside of a host cell.

Question 80

A specific animal virus has the ability to attach to and enter almost any animal host cell.