Deck 6: Viruses and Prions

Question 1

The core of every virus particle always contains ______.

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

Answer 1

either DNA or RNA

Question 2

Classi?cation 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) number of strands in the nucleic acid

Answer 2

biochemical reactions

Question 3

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

A) positive; negative
B) negative; positive
C) primary; secondary
D) secondary; primary
E) intermediate; primary

Answer 3

positive; negative

Question 4

A/an _______ is the protein shell around the nucleic acid core of a virus.

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

Question 5

Viral capsids are made from subunits called ______.

A) envelopes
B) spikes
C) capsomeres
D) prophages
E) peptones

Question 6

One of the principal viral capsid shapes is a 20-sided ?gure with 12 evenly spaced corners referred to as a/an _______ capsid.

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

Question 7

A negative RNA virus must ?rst ________.

A) synthesize a DNA copy of its genome
B) synthesize a negative RNA copy of its genome
C) synthesize a positive RNA copy of its genome
D) transcribe reverse transcriptase
E) transcribe RNA polymerase

Question 8

Viruses ______.

A) cannot be seen in a light microscope
B) are prokaryotic
C) contain 70S ribosomes
D) undergo binary ?ssion

Question 9

Viral nucleic acid types 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 10

A naked virus only has a/an ______.

A) capsomere
B) nucleocapsid
C) envelope
D) antigenic surface

Question 11

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 12

Helical and icosahedral are terms used to describe the shape of a viral ______.

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

Question 13

Viral spikes ________.

A) are always present on enveloped viruses
B) attach the viral capsid and envelope
C) allow bacteria to evade host defenses
D) are derived from host proteins
E) are for recognition among the various types of viruses

Question 14

Viruses exhibit all the following except ______.

A) de?nite shape
B) metabolism
C) genes
D) ability to infect host cells
E) ultramicroscopic size

Question 15

Which of the following represents a virus family name?

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

Question 16

Which of the following is not a typical capsid shape?

A) Tetrahedral
B) Complex
C) Helical
D) Icosahedron

Question 17

Reverse transcriptase synthesizes ________.

A) a positive RNA strand from a negative RNA strand
B) a negative RNA strand from a positive RNA strand
C) viral RNA from DNA
D) viral DNA from RNA

Question 18

All of the following pertain to virus envelopes except ________.

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

Question 19

Which of the following is not a viral order in the classi?cation system?

A) Caudovirales
B) Vaccinia virus
C) Nidovirales
D) Mononegavirales

Question 20

Which of the following is not associated with every virus?

A) Envelope
B) Capsomeres
C) Capsid
D) Nucleic acid
E) Genome

Question 21

Oncogenic viruses include all the following except ______.

A) hepatitis B virus
B) measles virus
C) Papillomavirus
D) HTLV-I and HTLV-II viruses
E) Epstein-Barr virus

Question 22

Which of the following is/are type(s) of cytopathic effects?

A) Inclusions in the nucleus
B) Multinucleated giant cells
C) Inclusions in the cytoplasm
D) Rounding of cells
E) All of the choices are correct.

Question 23

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 24

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 25

Persistent viruses that can reactivate periodically are ______.

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

Question 26

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 27

Viral tissue speci?cities are called ______.

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

Question 28

Which of the following occurs during assembly?

A) The nucleocapsid is formed.
B) New viral nucleic acid is formed.
C) Viral spikes insert in host cell membrane.
D) The nucleocapsid is formed and viral spikes insert in host cell membrane.
E) The viral envelope and the host cell membrane fuse.

Question 29

Mammalian viruses capable of starting tumors are ______.

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

Question 30

The envelope of enveloped viruses _______.

A) is identical to the host plasma membrane
B) is only composed of host endomembrane
C) does not contain spikes
D) is obtained by viral budding or exocytosis
E) makes the virus very susceptible to drug therapy

Question 31

Viruses attach to their hosts via ______.

A) host glycoproteins
B) host phospholipids
C) viral phospholipids
D) viral ?agella
E) carbohydrate attachments of the viral capsid

Question 32

The correct sequence of events in viral multiplication is ________.

A) penetration, uncoating, synthesis, adsorption, assembly, and release
B) uncoating, penetration, synthesis, assembly, absorption, and release
C) adsorption, penetration, uncoating, synthesis, assembly, and release
D) assembly, synthesis, uncoating, release, penetration, and adsorption
E) adsorption, release, synthesis, uncoating, assembly, and penetration

Question 33

Host range is limited by the _______.

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

Question 34

Viruses acquire envelopes around their nucleocapsids during ______.

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

Question 35

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 inde?nitely

Question 36

New, nonenveloped virus release occurs by ______.

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

Question 37

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 38

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 39

T-even phages ______.

A) include the poxviruses
B) infect Escherichia coli cells
C) enter host cells by engulfment
D) have helical capsids

Question 40

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

A) Viral sheaths
B) Tail ?bers
C) Nucleic acids
D) Capsid heads

Question 41

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 42

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

A) initial
B) primary
C) secondary
D) continuous
E) positive

Question 43

What type of phage enters an inactive prophage stage?

A) Primary
B) Secondary
C) Temperate
D) Temporary
E) Transformed

Question 44

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 45

Diagnosis of viral infections sometimes involves analyzing the patient's blood for speci?c _____ that the immune system produces against the virus.

A) glycoproteins
B) antibodies
C) complement proteins
D) antigens

Question 46

Infectious protein particles are called ______.

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

Question 47

Lysogeny refers to _______.

A) altering the host range of a virus
B) the latent state of herpes infections
C) virions exiting host cell
D) the viral genome inserting into bacterial host chromosome

Question 48

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

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

Question 49

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

A) patches
B) buds
C) plaques
D) cytopathic effects
E) pocks

Question 50

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

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

Question 51

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 52

In transduction, the viral genome _______.

A) initiates lysis of the host
B) includes DNA from the previous host
C) is replicated in the cytoplasm
D) is replicated in the nucleus

Question 53

The activation of a prophage is called ______.

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

Question 54

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 55

Viruses that infect bacteria are speci?cally called ______.

A) viroids
B) prions
C) bacteriophages
D) satellite viruses

Question 56

Infectious naked strands of RNA that affect plants are called ______.

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

Question 57

Creutzfeldt-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 58

Visible, clear, well-de?ned patches in a monolayer of virus-infected cells in a culture are called ______.

A) patches
B) buds
C) plaques
D) cytopathic effects
E) pocks

Question 59

Satellite viruses are _______.

A) also called viroids
B) dependent on other viruses for replication
C) the cause of spongiform encephalopathies
D) signi?cant pathogens of plants

Question 60

Cells grown in culture form a/an ______.

A) monolayer
B) bilayer
C) aggregate
D) plaque

Question 61

Animal viruses have the ability to attach to and enter almost any animal host cell.

Question 62

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

Question 63

Viruses mutate, and some viruses have not been discovered.

Question 64

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

Question 65

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

Question 66

Spikes are glycoproteins that can be found projecting from the viral capsid.

Question 67

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

Question 68

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

Question 69

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

Question 70

Who developed a rabies vaccine after realizing the disease was caused by something smaller than a bacterium?

A) Leeuwenhoek
B) Koch
C) Pasteur
D) Cohn
E) Ivanovski

Question 71

The primary purpose(s) of viral cultivation is/are to _______.

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

Question 72

Viruses are simple, noncellular, lacking mRNA and ribosomes.

Question 73

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

Question 74

A treatment for bacterial infections from the early 20th century has made a comeback; the use of bacterial viruses to eliminate bacterial infections. Which explanation most accurately describes the mechanism of action behind this treatment?

A) A wide variety of bacteria cause a large percentage of human infections, producing much sickness and death.
B) Viruses can infect bacteria, transferring pathogenic genes. The viral genes can then be suppressed, causing the bacteria to not replicate viruses.
C) The attachment structures on the virus and the receptors on the host cells make for exquisite speci?city of viruses for particular bacterial species.
D) Antibiotic resistance in humans is on the increase, so using a different kind of therapy is more bene?cial.

Question 75

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

Question 76

Each virus is classified into a genus based on its host, target tissue, and type of disease it causes.

Question 77

Viruses are not filterable.

Question 78

Some animals can become infected with multiple in?uenza virus strains usually associated with other animals. Which statement below describes the result of these infections?

A) A new novel strain of ?u may be produced, for which the human population has no immunity.
B) Major genetic variations in the ?u viruses can be reproduced.
C) The viral genomes within the host cells can become recombined.
D) All of the choices are correct.

Question 79

Viruses are unable to multiply outside of a host cell.

Question 80

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