Chapter 6 Flashcards

1
Q

What is the capsid?

A

External shell surrounding the virus’s nucleic acids

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2
Q

What types of cells can viruses infect?

A

Bacteria, algae, fungi, protozoa, plants, animals (all types)

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3
Q

How are viruses referred to?

A

As infectious particles that are either active or inactive

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4
Q

What are some of the cytopathic effects that can occur?

A

Disoriented cells, changes in cell shape/size, development of intracellular damage

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5
Q

What are oncogenic viruses?

A

Viruses that have the ability to cause cancer

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6
Q

What are in vitro methods?

A

Viral cultivation methods that occur in cell or tissue culture

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7
Q

What is nucleocapsid?

A

Term referring to the capsid and nucleic acid together

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8
Q

What are spikes?

A

Projections from the nucleocapsid or envelope that allow viruses to dock with their host cells

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9
Q

What is the genome?

A

The full complement of DNA and RNA carried by a cell

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10
Q

What are reverse transcriptases?

A

Enzymes that synthesize DNA from RNA

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11
Q

How were viruses discovered?

A

By filtering bacteria out of fluid and realizing the fluid was still infectious

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12
Q

What are primary cell cultures?

A

Freshly isolated animal tissue that is cultured to produce a monolayer with the characteristics of the original tissue

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13
Q

What are complex capsids?

A

Capsids found in bacteriophages that form unsymmetrical shapes

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14
Q

What is uncoating?

A

Enzymes in the vacuole dissolve the envelope and capsid, releasing the virus into the cytoplasm

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15
Q

What are capsomeres?

A

Identical protein subunits that spontaneously self-assemble to form the capsid

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16
Q

What are viroids?

A

Viruslike agents that parasitize plants and are composed of naked strands of RNA only

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17
Q

What is lysogenic converison?

A

The acquisition of a new trait from a temperate phage

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18
Q

What are bacteriophages?

A

Viruses that infect bacteria

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19
Q

What is the virus envelope?

A

A modified piece of host cell membrane that is found on some, but not all, viruses

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20
Q

What are arenaviruses?

A

Viruses that pack along host cell ribosomes

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21
Q

What genes do viruses possess?

A

Only those necessary to invade host cells and redirect their activity

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22
Q

What is negative-sense RNA?

A

RNA genomes that need to be converted into the proper form to be made into proteins

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23
Q

Why do scientists develop vaccines to viruses as opposed to therapies?

A

Viruses mutate rapidly, thus making therapy design difficult

24
Q

What are the characteristics of bacteriophage infections?

A

Infect every known bacterial species, make bacteria more pathogenic to humans

25
Q

What are inclusion bodies caused by viruses?

A

compact masses of viruses or damaged cell organelles in the nucleus or cytoplasm

26
Q

What is a naked virus?

A

A virus that consists of only the nucleocapsid

27
Q

What are in vivo methods?

A

Viral cultivation methods that occur in lab animals or embryonic bird tissues

28
Q

What is a virion?

A

Fully formed virus capable of establishing infection

29
Q

What are polymerases?

A

Enzymes that synthesize DNA and RNA

30
Q

What are prophages?

A

an inactive state in which phage DNA is inserted into the host chromosome

31
Q

What is induction?

A

Activation of a prophage in a lysogenic cell that leads to a lytic cycle

32
Q

How are enveloped viruses liberated?

A

Budding or exocytosis

33
Q

Where do DNA viruses replicate?

A

Nucleus

34
Q

What is positive-sense RNA?

A

Single-stranded RNA genomes ready for immediate translation into proteins

35
Q

What are satellite viruses?

A

Viruses that depend on other viruses for replication

36
Q

What constitutes the informal classification system for viruses?

A
  1. Animal, plant, or bacterial virus
  2. Enveloped or naked
  3. DNA or RNA
  4. Helical or Icosahedral
37
Q

What is the host range?

A

The range of host cell types that a virus can infect

38
Q

What are retroviruses?

A

Viruses that “borrow” the host’s tRNA molecules

39
Q

What is chronic latent state?

A

Periodic reactivation after a period of viral inactivity

40
Q

What is Interferon?

A

A naturally occurring human cell product that has shown success in preventing and treating viral infections

41
Q

What happens to a virus during endocytosis?

A

Entire virus in engulfed by the cell and inclosed in a vesicle or vacuole

42
Q

What is a lytic cycle?

A

bacteriophage cycle that ends in bacterial cell destruction

43
Q

What are temperate phages?

A

Bacteriophages that can undergo adsorption and penetration but do not immediately undergo replication and release

44
Q

What are prions?

A

Distinct protein fibrils found in the brain tissue of animals with encephalopathies

45
Q

What two parts are every virus formed from?

A

External coating and core containing nucleic acids

46
Q

What are the two main capsid shapes?

A

Helical and Icosahedral

47
Q

What is a lysogenic cycle?

A

bacteriophage cycle in which the bacteriophage becomes incorporated into host cell DNA

48
Q

What are replicases?

A

Enzymes that copy RNA

49
Q

What are cytopathic effects?

A

Virus-induced damage to the cell that alters its microscopic appearance

50
Q

What are the properties of viruses?

A
  1. Not cells and do not fulfill characteristics of life
  2. Obligate intracellular parasites that rely on host cell for reproduction
  3. Can have dsDNA, ssDNA, dsRNA, or ssRNA, but not more than one
  4. Lack enzymes and protein synthesizing machinery
51
Q

What is adsorption?

A

The attachment of the virion to the host cell

52
Q

Where do RNA viruses replicate?

A

Cytoplasm

53
Q

What are the general phases in the “life cycle” of animal viruses?

A
Adsorption
Penetration
Uncoating
Synthesis
Assembly
Release
54
Q

What is a provirus?

A

Virus whose DNA is incorporated into the DNA of the host

55
Q

What are syncytia?

A

Fusions of multiple host cells into single large cells containing multiple nuclei

56
Q

What are the purposes of viral cultivation?

A

Isolation and identification
Preparation for vaccines
Research

57
Q

What are plaques?

A

Clear, well-defined patches in the cell sheet caused by radiating patterns of viral infection