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VIrology > Chapter 1 > Flashcards

Chapter 1 Flashcards

1
Q

who is the father of virology?

A

dimitri ivanovsky

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2
Q

Dimitri Ivanovsky did what?

A
  • Russian biologist (botanist)
  • Reported that the infectious component of tobacco mosaic disease could pass through a porcelain filter that removed bacteria and fungi (1892)
  • “filter-passing”
  • Did not isolate a virus particle
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3
Q

who is martinus Beijerinck?

A
  • Dutch microbiologist and botanist
    infectious agent could replicate in plants, therefore not a toxin (1898)
  • Used the term
  • Contagium vivum fluidim (infectious living liquid) to describe his findings
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4
Q

who was Ernst Ruska?

A
  • german physicist

- visualization of viruses didn’t occur till 1930s with the microscopy advent of electron microscopes

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5
Q

how did yellow fever originate?

A

from africa, spread to the new world with slave trade

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6
Q

what was the first human disease whose causative agent was identified as a virus?

A

yellow fever

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7
Q

Jesse William Lazear preformed what two tests?

A
  1. Volunteers slept in clothes and beds of yellow fever patients (but had mosquito nets) (did not get sick)
  2. Volunteers stayed away from patients but were exposed to mosquitoes that fed on yellow fever patients
    (all got sick)
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8
Q

yellow fever was spread by?

A

insect vector

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9
Q

you need____ and ___ cells to culture viruses

A

live and replicating

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10
Q

what is a virus?

A
  • A subcellular ‘organism’ with a parasitic life cycle
  • Needs a host cell to replicate
  • Has no metabolic activity outside of the host cell
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11
Q

a virus’s infection may be lytic or latent meaning?

A

lytic (causing cell death)

latent (viral genome remains dormant in host cell)

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12
Q

oncogenic

A

cancer causing

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13
Q

what are the abilities that prove viruses to be alive

A
  • Ability to replicate
  • Evolve
  • Contain nucleic acids
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14
Q

what are the abilities that prove viruses not to be alive

A
  1. Energy production
  2. Respiration
  3. Response to negative environments
  4. Locomotion
  5. Growth
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15
Q

virus particles bind to ____ cells

A

target

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16
Q

viral genome replicates _____ the cell

A

within

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17
Q

what is the viron?

A
  • virus particle, a single infectious agent

- Made of nucleic acid genome (DNA or RNA) protected by a protein shell

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18
Q

what is the capsid?

A

protein structure surrounding viral genome

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19
Q

Capsomers

A

repeating protein subunits that form the capsid

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20
Q

envelope

A

derived from host cell lipid bilayer, covers virus capsid

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21
Q

Nucleoproteins

A

proteins that surround the viral genome (either structural or replicative proteins)

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22
Q

Nucleocapsid

A

nucleic acids, structural, and replicative proteins

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23
Q

what is a tegument?

A

Thick group of proteins underneath envelope

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24
Q

enveloped virus:

A
  • RNA genome
  • Nucleoproteins
  • Nucleocapsid
  • Capsid
  • Envelope
  • Glycoproteins
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25
Q

non enveloped virus:

A
  • DNA genome
  • Nucleoproteins
  • Capsid
  • Nucleocapsid
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26
Q

what are the 4 standard morphological groups?

A
  1. non enveloped /helical capsid
  2. non enveloped/ icosahedral capsid
  3. enveloped/ helical capsid
  4. enveloped/icosahedral capsid
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27
Q

How is the capsid formed?

A

repeating protein subunits (capsomers)

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28
Q

capsids arent capable of self assembly (T F)

A

false, they are

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29
Q

what is the morphology of capsids?

A

helical or complex

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30
Q

describe icosahedral symmetry

A

symmetry is based on the presence of the correct axes of symmetry

  • 2 fold axes of rotational symmetry about the face edge
  • 3 fold axes of rotational symmetry about the face centre
  • 5 fold axes of rotational symmetry about the face vertex
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31
Q

what is the symmetry of picornovirus?

A

dodecahedron

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32
Q

what is the symmetry of adenovirus?

A

hexameric

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33
Q

the picornavirus is a __________ capsid protein

A

4 (VP1 VP2 VP3 VP4)

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34
Q

the adenovirus is made up of __________ hexon subunits

and ____________ proteins in total

A

20, 11

35
Q

the poxvirus has a very _______ genome and expresses more than 100 proteins

A

large

36
Q

`the flivovirus has a ____ nucleocapsid

A

helical

37
Q

when was the last outbreak of smallpox?

A

1997

38
Q

*what did jesse lazear determine was the vector of yellow fever?

A

mosquitos

39
Q

the virus envelope is derived from the __________ _________

A

host membrane

40
Q

viral glycoproteins are ________

A

hydrophilic

41
Q

lipids cannot be inserted into the envelope (T F)

A

false (they can)

42
Q

lipids cannot be inserted into the envelope (T F)

A

false (they can)

43
Q

the viral genome has eirther _____or _____

A

DNA or RNA but not both

44
Q

can the viral genome be single or double stranded?

A

yes

45
Q

viruses are the only known form of life that can have a genome made of RNA (T F)

A

T

46
Q

the genome size is related to the ________ of the virus

A

complexity

47
Q

____ has one of the largest genomes that can infect humans?

A

poxvirus

48
Q

_________ has the smallest genome infecting humans

A

parvovirus

49
Q

_________ has the smallest genome infecting humans

A

parvovirus

50
Q

viruses use ________ to maximize functionality from limited genome sequence

A

frameshifting

51
Q

each amino acid is encoded by 3 bases called a ____

A

codon

52
Q

what is RNA splicing?

A

cut and joins viral mRNA to produce different proteins from one original RNA molecule

53
Q

even in the largest virus genome _______ codes for proteins

A

90%

54
Q

DNA viruses are replicated by _____ processes or _____ processes

A

cellular or simple

55
Q

DNA viruses form replication centers in what 2 places?

A

cytoplasm or nucleus

56
Q

what do host DNA polymerases do?

A

check the sequence

57
Q

for RNA viruses replication usually involves _____ cell machinery

A

host

58
Q

are RNA viruses proofread?

A

no

59
Q

RNA viruses have a ______ mutation rate

A

high

60
Q

RNA viruses have a _______ genome to decrease the mutation rate

A

segemnted

61
Q

what is antigenic drift and which viruses use it?

A

RNA viruses use to confer immune escape advantage

62
Q

*A larger genome means more complex virus ( T F)

A

T

63
Q

HIV is one of the most rapidly ________ viruses

A

changing

64
Q

is HIV segmented

A

non segmented

65
Q

is HIV segmented

A

non segmented

66
Q

HIV has a ____ genome

A

diploid

67
Q

what are the 4 hypothesis for HIV mutation rates?

A
  1. reverse transcriptase is a low fidelity polymerase, each genome copy will be different from its parental template
  2. Reverse transcriptase jumping from one genome to the other could introduce errors
  3. Multiple HIV particles infecting the same cell, genomes could reassort
  4. Recombination during DNa integration and excision, recombination rate would be high
68
Q

what is the result of HIV mutation rates?

A

incredible immune invasion capabilities

69
Q

what is the result of HIV mutation rates?

A

incredible immune invasion capabilities

70
Q

does every ifnection cause disease?

A

no

71
Q

describe the effect infection causing disease?

A

mostly observed in viruses who have jumped to new host

- some symptoms cause imune response, ex. ebola

72
Q

what is asymptomatic ?

A

no symptoms or flare ups

- latent HSV 1

73
Q

what is asymptomatic ?

A

no symptoms or flare ups

- latent HSV 1

74
Q

describe how viruses modulate the host cell?

A
  • take over protein synthesis machinery
  • have mechanisms to maike host cell recognize viral mRNA
  • control the immune response
75
Q

what are the types of virus infection?

A
  • transforming
  • latent
  • acute
  • chronic
76
Q

describe a lytic infection:

A
  • cell lysis following production of viral particles

- rapid cell death

77
Q

what causes cell lysis?

A
  • viral enzymes
  • indirect damage of producing so many viral particles
  • breakdown of membrane integrity
78
Q

describe persistent or chronic infections:

A

Infections that produce small amounts of virus over a long period of time because the immune system doesnt recognize viral antigens
ex. hep B hep C

79
Q

describe a latent infection

A

viral genome is present but not active within the cell, only a small portion of viral genome is active

80
Q

there is __ RNA LAT involved in the reactivation of HSV 1

A

3

81
Q

what is a provirus?

A

the genetic material of a virus is incorporated into and able to replicate as part of the genome of a host cell

82
Q

what is oncogenesis?

A
  • loss of regulation of cell growth
  • Changes to cell appearance and structure
  • Abnormal chromosome numbers (aneuploidy)
  • Altered transcription and production of growth factors
  • Uninhibited cell growth
83
Q

what is retroviridae?

A

viruses can insert their genome into the hosts causing mutations

VIrology (5 decks)

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