Lecture 1: General Virology 1 Flashcards

1
Q

Define a virus and how does that compare to bacteria

A
  • Filterable (virus - <200um) – retain bacteria but allow smaller (0.22um)
  • Obligate intracellular (depend on host mechanisms)
  • No organelles (can acquire non-functional ribosomes from host)
  • either DNA/RNA
  • Require electron microscopy to view

Bacteria can have independent metabolism, they are larger, and have DNA/RNA, can see with light microscope

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2
Q

Which virus has organelles

A

arenavirus
non functional ribosome

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3
Q

2 types of viral structure

A
  • Naked: genome + protein coat (capsid)
  • Enveloped: genome + protein coat + lipid bilayer
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4
Q

What is a Pasteur-Chamberland filter

A
  • 0.1 – 1 um
  • Remove all bacteri/cells from liquid suspension
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5
Q

Which type of viral structure can you remove easily by washing hands

A

enveloped

o Lipid bilayer makes it more vulnerable to desiccation/detergents vs naked

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6
Q

How does a virus get an envelope

A

o Viral enveloped from host cell membrane
o Bilayer contains virus coded membrane proteins – genome and capsid move into the bilayer with the glycoproteins
o Virus can acquire host proteins in bilayer
o Proteins in bilayer determine range and antigenic composition

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7
Q

What is the largest and smallest virus

A

Pithovirus sibericum - 1.5 um
Human papilloma virus - 100nm

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8
Q

What virus has the largest genome

A

pandora virus
1 um
2.5 million bp

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9
Q

What are bacteriophages

A

viruses that infect bacteria
o Used as biological control agent – specific
o No relevant associated animal diseases

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10
Q

What large virus can act like a bacteria

A

acanthamoeba polyphagia mimivirus

large size
“mimic microbe” - gram stains positive like bacteria

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11
Q

What is the smallest virus?

A

circovirus

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12
Q

What is the largest virus? (mammal)

A

poxvirus

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13
Q

What is the largest virus? (amoeba)

A

pithovrius

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14
Q

How are virus naming classifications organized? 2 ways

A
  • Linnaean hierarchical system (phylum/class/order…) –
    o should not be used for virus – high mutation rate/small genome
    o can’t classify beyond the order (class/phylum) - can use family/genus/species

use the ICTV (international committee of taxonomy of viruses)
* order: - virales
* family: -viridae
* subfamily: -virinae
* genus: -virus
* species: -virus

Baltimore classification
o dsdNA
o ssDnA
o dsDNArt
o dsRNA
o ssRNA
o ssRNA(-)
o ssRNA(+)
o ssRNArt

based on genome and method of transcription

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15
Q

Which dsDNA virus carries its own transcriptase/enzymes for transcription

A
  • most use host enzymes for transcription except pox virus – carries own enzymes
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16
Q

5 examples of dsDNA viruses

A
  • examples: adeno/hepadna/herpes/papilloma/polyoma
17
Q

Where does the pox virus replicate? how does that compare to other viruses of that same category?

A

dsDNA virus
pox virus replicated in the cytoplasm because it already has the enzymes needed for transcription

the rest of the dsDNA viruses replicate in the nucleus because it has to use the cells machinery/enzymes

18
Q

6 examples of ssRNA(+) viruses

A
  • example: picona/flavi/calci/astro/corona/retro
19
Q

How do retroviruses function

A
  • genome can act as mRNA except retrovirus – use reverses transcriptase and integrase to convert RNA to DNA

retroviruses go to nucleus and incorporate into host genome using integrase

20
Q

2 examples of dsRNA and how do they worK?

A
  • example: reo/birna
  • has RNA dependent RNA polymerase to make mRNA
21
Q

7 examples of ssRNA (-) and how do they worK?

A
  • example: rabdo/filo/borna/paramyxo/orthomyxo/bunya/delta
  • has viral RNA dependent RNA polymerase to make mRNA
22
Q

Where do all RNA viruses replicate

A

cytoplasm

except:
retro

23
Q

Where do all DNA viruses replicate

A

nucleus

except:
pox

24
Q

What is the function of the 3 parts of a virus

A

genome: contains information
caspid: protection
envelope: glycoproteins provides a receptor for entry into host cells