Deck 6: An Introduction to Viruses

Question 1

All of the following pertain to virus envelopes except they

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

Answer 1

E

Question 2

When used in a description of viruses, the term replication includes

A) the production of multiple copies of a virus by a host cell.
B) the copying of the viral DNA in a DNA virus.
C) the copying of the genomic RNA in an RNA virus.
D) All of these choices are correct.

Answer 2

D

Question 3

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 these choices are correct.

Answer 3

B

Question 4

Which of these structures are used by bacteriophages to attach to host cell receptors?

A) sheath
B) tail fibers
C) nucleic acid
D) capsid head

Question 5

Which of the following represents a virus family name?

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

Question 6

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 7

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) always lyse the host cells
E) occur when temperate phages enter host cells

Question 8

Viral capsids are made from subunits called

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

Question 9

Viruses acquire envelopes around their nucleocapsids during

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

Question 10

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

A) nucleus; cytopl
B) cytopl; cell membrane
C) cell membrane; cytopl
D) cytopl; nucleus
E) nucleus; endoplic reticulum

Question 11

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 12

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.
E) All of these choices are correct.

Question 13

Host cells of viruses include

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

Question 14

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

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

Question 15

All of the following are characteristics of viruses except

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

Question 16

Which of the following is not associated with every virus?

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

Question 17

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 18

Which of the following is correct about viruses?

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

Question 19

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 20

The core of every virus particle always contains

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

Question 21

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 22

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 these choices are correct.

Question 23

The capsomers are made of

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

Question 24

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

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

Question 25

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 26

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

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

Question 27

Which of the following is a type of cytopathic effect?

A) inclusions in the nucleus
B) multinucleated giant cells
C) inclusions in the cytopl
D) rounding of cells
E) All of these choices are correct.

Question 28

Infectious naked strands of RNA are called

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

Question 29

Viruses that consist of only a nucleocapsid are considered

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

Question 30

Infectious protein particles are called

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

Question 31

All of the following are 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 these choices are correct.

Question 32

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 33

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 34

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

A) lysogeny.
B) budding.
C) plaques.
D) pocks.

Question 35

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 effect.
E) pocks.

Question 36

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 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 these choices are correct.

Question 38

Viruses belong to which of the following Kingdoms?

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

Question 39

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 40

Creutzfeldt-Jakob 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 41

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

Question 42

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

Question 43

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

Question 44

A naked virus does not have an) _____.

Question 45

Spikes are glycoproteins of the virus capsid.

Question 46

The Adeno-Associated Virus AAV) and the Delta Agent are prions.

Question 47

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

Question 48

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

Question 49

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

A) lytic phase
B) budding
C) adsorption
D) lysogenic conversion
E) latent phase

Question 50

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

Question 51

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

Question 52

Viruses that infect bacteria are specifically called _____.

Question 53

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

Question 54

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 55

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

Question 56

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

Question 57

How do enveloped animal viruses exit their host?

A) budding or exocytosis
B) bursting the host cell
C) rupturing the virus
D) endocytosis

Question 58

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

Question 59

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

Question 60

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

Question 61

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

Question 62

Viral replication can involve the copying of RNA in an RNA virus.

Question 63

Which type of virus is most likely to cause the immediate damage and destruction of an infected animal cell when it is released?

A) enveloped virus
B) RNA virus
C) nonenveloped virus
D) DNA virus

Question 64

Discuss theories regarding the origins of viruses and make a case for whether viruses originated before cellular life-forms or after cellular life-forms.

Question 65

Select the FALSE statement about viruses.

A) Cellular life-forms most likely preceded the origin of viruses since viruses need host cells in which to develop and reproduce.
B) Viruses are the most numerous microbes on Earth.
C) Viruses have impacted the evolution of all other cellular life-forms including bacteria, achaeans, and eukaryotes.
D) When viruses are treated in a way that prevents them from entering host cells and reproducing, they are said to be dead.

Question 66

Which of the following viral types enter animal cells via fusion with the animal cell membrane?

A) enveloped viruses
B) non enveloped viruses
C) naked viruses
D) All of these choices are correct.

Question 67

Compare and contrast viruses, prions, and viroids.

Question 68

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

Question 69

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

Question 70

Noneveloped viruses enter their animal host cell via an active process that requires the participation of the animal cell.

Question 71

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

Question 72

While of the following techniques or tools has provided information regarding the nature of viruses, which one had to be developed before the genetics, biochemistry, and life cycles of viruses could be thoroughly studied?

A) scanning electron microscopy
B) viral cultivation techniques
C) transmission electron microscopy
D) serological techniques

Question 73

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

Question 74

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

Question 75

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

Question 76

The descriptive groupings of virus into categories such as icosahedral and helical are based on

A) the type of nucleic acid.
B) the shape of the nucleocapsid.
C) the presence or absence of an envelope.
D) the mechanism of entry into host cells.

Question 77

What tool or technique used by Ivanowski and Beijerinck while studying diseased tobacco plants enabled them to determine that the disease was caused by an agent significantly smaller than bacteria?

A) scanning electron microscopy that enabled them to view the virus the tobacco mosaic virus
B) transmission electron microscopy that allowed them to view the tobacco mosaic virus
C) porcelain filters that trapped bacteria but allowed passage of the virus
D) cell culture that enabled cultivation of the virus

Question 78

The three basic groups of viruses based on morphology include

A) enveloped viruses, non enveloped viruses, and complex viruses.
B) enveloped viruses, DNA viruses, and non enveloped viruses.
C) helical viruses, round viruses, and enveloped viruses.
D) non enveloped viruses, RNA viruses, and bacteriophages.