Deck 6: An Introduction to Viruses

Question 1

The virus-induced, specific damage to the host cell that can be seen in a light microscope is called

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

Answer 1

D

Question 2

Which 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

Answer 2

D

Question 3

Which of the following is not associated with every virus?

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

Answer 3

A

Question 4

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 5

Host cells of viruses include

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

Question 6

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

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

Question 7

Viruses have all the following except

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

Question 8

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 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 9

These 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 are correct.

Question 10

The core of every virus particle always contains

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

Question 11

Viruses acquire envelopes around their nucleocapsids during

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

Question 12

All of the following pertain to virus envelopes except they

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

Question 13

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)blood agar

Question 14

The correct sequence of events in viral multiplication is

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

Question 15

Which of the following is correct about viruses?

A)cannot be seen with a light microscope
B)are procaryotic
C)contain 70S ribosomes
D)undergo binary fission
E)can be grown on nutrient agar

Question 16

Virus capsids are made from subunits called

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

Question 17

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 18

Which of the following represents a virus family name?

A)Herpes simplex virus
B)Herpesviridae
C)Picornavirus
D)Enterovirus
E)Hepatitis B virus

Question 19

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 20

Classification of viruses into families involves determining all the following characteristics except

A)type of nucleic acid.
B)type of capsid.
C)presence of an envelope.
D)biochemical reactions.
E)nucleic acid strand number.

Question 21

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 22

The nucleocapsid consists of

A)the capsomers assembled into the capsid.
B)the nucleic acid of the virus only.
C)the nucleic acid along with the capsid.
D)the envelope and capsid.
E)the envelope, nucleic acid, and capsid.

Question 23

Infectious naked strands of RNA are called

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

Question 24

Oncogenic viruses include all the following except

A)hepatitis B virus.
B)measles virus.
C)papillomavirus.
D)HTLVI and HTLVII viruses.
E)Epstein-Barr virus.

Question 25

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 round up
E)All of the choices are correct.

Question 26

All of the following is correct about treating viral diseases except

A)viruses are killed by the same antibiotics that kill bacteria.
B)many antiviral drugs block viral replication.
C)many antiviral drugs cause severe side effects.
D)interferons show potential for treating and preventing viral infections.
E)All of the choices are correct.

Question 27

When a virus enters a lysogenic phase, it means

A)the virus is integrated into the DNA of the host cell and is latent.
B)the virus is bursting through the host cell membrane.
C)the virus is starting biosynthesis of its nucleic acid.
D)the virus will remain in circulation and not continue infecting its host.
E)the number of viruses in the host is decreasing as the immune system becomes effective.

Question 28

Which body system is mainly affected by Creutzfeldt-Jakob disease?

A)digestive
B)genitourinary
C)nervous
D)circulatory
E)respiratory

Question 29

Which of the following viruses did D.Ivanovski and M.Beijerinck work with?

A)rabies
B)smallpox
C)tobacco mosaic virus
D)herpes
E)Epstein-Barr virus

Question 30

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 31

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 32

Viruses that consist of only a nucleocapsid are considered

A)simple viruses.
B)complex viruses.
C)naked viruses.
D)viroids.
E)incomplete viruses.

Question 33

Viral growth in bird embryos can cause discrete, opaque spots in the embryonic membranes called

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

Question 34

Viruses belong to which of the following Kingdoms?

A)Protists
B)Fungi
C)Archaea
D)Bacteria
E)None of the choices are correct.

Question 35

All of the following are characteristics of viruses except

A)they can be crystallized.
B)they often have a geometric capsid.
C)they have a viscous fluid inside their capsids.
D)they can cause fatal diseases.
E)they can cause mild diseases.

Question 36

The capsomers are made of

A)DNA.
B)RNA.
C)lipids.
D)protein.
E)carbohydrate.

Question 37

Uncoating of viral nucleic acid

A)does not occur in bacteriophage multiplication.
B)involves enzymatic destruction of the capsid.
C)occurs during penetration in the multiplication cycle.
D)occurs before replication.
E)All of the choices are correct.

Question 38

Infectious protein particles are called

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

Question 39

Which of the following parts of a virus is not always present?

A)envelope
B)nucleic acid
C)capsid
D)capsomers
E)None of the choices are optional parts of a virus.

Question 40

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 41

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

Question 42

Viruses that infect bacteria are specifically called _____.

Question 43

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

Question 44

No cases of variant Creutzfeldt-Jakob syndrome linked to eating infected cows have occurred in the United States.

Question 45

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

Question 46

A naked virus does not have an _____.

Question 47

Viral infections are easier to treat with drugs than bacterial infections.

Question 48

Diagnosis of viral infections sometimes involves analyzing the patient's blood for specific _____ that the immune system produced against the virus.

Question 49

The International Committee on Taxonomy of Viruses has determined that there are only three orders of viruses.

Question 50

How do enveloped animal viruses exit their host?

A)Budding or exocytosis
B)Bursting the host cell
C)Rupturing the virus
D)Endocytosis
E)None of these are correct

Question 51

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

Question 52

The adeno-associated virus (AAV) and the delta agent are prions.

Question 53

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

Question 54

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

Question 55

Spikes are glycoproteins of the virus capsid.

Question 56

Clostridium botulinum is made virulent by incorporated prophage genes encoding for the botulinum toxin.What term describes this process?

A)Lytic phase
B)Budding
C)Adsorption
D)Lysogenic conversion
E)Latent phase

Question 57

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

Question 58

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

Question 59

Freshly isolated animal tissue that is placed in a growth medium and allowed to produce a cell monolayer is referred to as a _____ cell culture.

Question 60

Bacteriophages do not undergo adsorption to specific host cell receptors prior to penetration.

Question 61

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

Question 62

Explain what is meant by host range, what governs host range, and what is meant by tissue tropism.

Question 63

Compare and contrast viruses, prions, and viroids.

Question 64

Compare and contrast the steps of viral multiplication cycles in bacteriophages and animal viruses.

Question 65

Discuss the criteria used for classifying viruses into families and genera.

Question 66

Discuss why it is difficult to trace the origins of viruses and why they are important.

Question 67

Discuss at least six characteristics that are unique to viruses compared to other microorganisms.

Question 68

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