Lec 62: Basic Virology Flashcards Preview

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Flashcards in Lec 62: Basic Virology Deck (23):
1

What is unique about viral replication compared to other pathogens?

  • Obligate Parasites: cannot replicate on their own, lack the machinery to repliate genome 
  • Must infecy host to replicate 

2

What are the key structural components of the viruses?

  • proteins
  • envelope
  • nucleic acids

3

Describe the types and characteristics of viral proteins.

  • Found in all viruses
  • Capsids
    • structural proteins
    • Icosahedra, Helical
  • Enzymes 
  • M proteins

4

Describe the components of the enveloped vs. non-enveloped viruses.

  • enveloped
    • found only in some viruses
    • composed of lipids
    • makes virus susceptible to detergents 
  • non-enveloped
    • glycoprotein layer 
    • very hearty, resistant 

5

What are the classifications of DNA viruses?

  • Enveloped
    • dsDNA (linear)
    • dsDNA (circular)
  • Non-enveloped
    • dsDNA (circular) 
    • ssDNA (linear) 
    • dsDNA (linear)

6

What are the classifications of RNA viruses?

  • Enveloped 
    • retrovirus (+ssRNA ---> DNA intermediate)
    • -ssRNA
    • +ssRNA
  • Non-enveloped
    • +ssRNA
    • dsRNA

7

What are the 7 virus types according to Baltimore Classification?

  1. Group I: dsDNA
  2. Group II: +ssDNA
  3. Group III: dsRNA
  4. Group IV: +ssRNA
  5. Group V: -ssRNA
  6. Group VI: +ssRNA (reverse transcription)
  7. Group VII: dsRNA (reverse transcription)

8

What are the goals of viral replication?

  1. make viral proteins
  2. duplicate viral genome

9

Where do RNA viruses generally replicate? Where do DNA viruses generally replicate?

RNA: cytoplasm

DNA: nucleus 

10

Describe the major viral replication enzymes, their roles, and their sources.

  1. RNA-dependent RNA polymerase
    • ​​replicates RNA from RNA template
    • source: all RNA virses
  2. RNA-dependent DNA polymerase
    • reverse transcriptase, reverse transcribes RNA to DNA
    • source: virus
  3. DNA-dependent RNA polymerase
    • ​​transcribes RNA from DNA template 
    • source: host 
  4. DNA polymerase
    • ​replicates DNA from DNA
    • source: host/virus

11

What are the steps in the viral replication cycle?

  1. attachment & entry into host cell 
  2. viron uncoating
  3. transcription of viral mRNA
  4. translation of viral mRNA (viral protein production)  
  5. replication of viral genome 
  6. assembly of virons (viral proteins encapsulate viral genes)
  7. virons released from host cell via budding or lysis

12

What do all viruses transcribe before protein translation?

mRNA (+ssRNA)

 

13

 What is the general process of viral protein synthesis?

General Process: Viral DNA/RNA --> mRNA --> proteins

Exception: Viral RNA retrovirus --> DNA --> mRNA --> proteins

14

+ssRNA replication

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15

-ssRNA replication

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16

dsRNA replication

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17

RNA retrovirus replication

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18

dsDNA retrovirus replication

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19

ssDNA replication

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20

dsDNA replication

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21

What is cytopathic effect (CPE)?

morphological changes that occur in cells during many viral infection: ballooning, rounding, lysis, giant cell (syncitium), or inclusion body formation

22

What is Viral Latency?

  • virus becomes dormant and ceases production of new virus to hide from immune system
  • virus can reactivate at any time, life-long persistence 
  • ex. herpes simplex virus  

23

What is viral tropism?

specificity of a virus for a specific host tissue; determined by interaction between host cell receptors and viral glycoproteins

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