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RUSVM Virology > Replication of Viruses > Flashcards

Replication of Viruses Flashcards

1
Q

Nuclear Spread of Virus Genome

A

Viral genome is integrated into the host cell genome and passed down to next progeny or generation of host cell

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2
Q

Assembly and Maturation

A

Assembly of virus genome and proteins into new virions follows a specific order, all components are packaged to form mature virions

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3
Q

Result of splicing

A

mRNA having different coding information derived from a single gene

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4
Q

Burst Size

A

Number of infectious virions released per average cell

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5
Q

Fusion Proteins

A

Found on the surface of the virus, facilitate membrane fusion

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6
Q

Adsorption

A

During this period, virus attaches to and enters the cells, and the titer of free virus in the medium may actually decline

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7
Q

Intercellular Spread

A

Spread from cell to cell without contact with extracellular environment

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8
Q

Replication of (+) single stranded RNA with Reverse Transcriptase

A
  • (+)ssRNA → RNA Dependent DNA Polymerase → (-) ssDNA → DNA Dependent DNA Polymerase → dsDNA Intermediate
  • (-)dsDNA Intermediate → DNA Dependent RNA Polymerase → (+)mRNA → Viral Protein
  • (-)dsDNA Intermediate → DNA Dependent RNA Polymerase → (+)ssRNA → Viral Genome
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9
Q

Exocytosis

A

Vesicles containing virus migrate to plasma membrane and released

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10
Q

Replication of (+) single strand RNA

A
  • (+)ssRNA → Translates Directly → (+) mRNA → Viral Protein
  • (+)ssRNA → RNA Dependent RNA polymerase → (-)ssRNA
  • (-)ssRNA → RNA Dependent RNA Polymerase → (+) mRNA → Viral Protein
  • (-)ssRNA → RNA Dependent RNA Polymerase → (+)ssRNA
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11
Q

Mechanisms of intercellular transmission of viruses

A

Cell to Cell plasma membrane fusion

Passage across tight junction

Movement across a neural synapse

VIral induction of actin or tubulin

Subversion of actin containing structures form filopodial bridges

Membrane nanotube subversion

Virological synapse

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12
Q

Monocistronic mRNA

A

mRNA that encodes one polypeptide

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13
Q

Co-Receptor

A

Additional cell surface molecule required for entry when binding to a cellular receptor is not sufficient for infection

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14
Q

Exon

A

Portion of a gene that encods for amino acids

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15
Q

Replication of double stranded RNA

A
  • (-)dsRNA → RNA Dependent RNA Polymerase → (+) mRNA → Viral Protein
  • dsRNA → RNA Dependent RNA Polymerase → dsRNA → Viral Genome
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16
Q

Pore-Mediated Penetration

A

Inject their genome into the host cytoplasm throug the creation of a pore in the host membrane

________________________________

Non-Enveloped Viruses

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17
Q

Eclipse Period

A

Time interval between uncoating (disappearance of viruses) and appearance intracellularly of first infectious progeny virions.

_______________________

No infectious virus can be detected

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18
Q

Steps of Virus Replication

A

Attachment

Penetration

Uncoating

Synthesis of Viral Components

Assembly and Maturation

Release

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19
Q

Viral Protein and Nucleic Acid Synthesis

A

Flow of genetic information in eukaryotic cell

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20
Q

Function of the PolyA Tail

A

Interact with polyA binding protein - translation

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21
Q

Splicing

A

Process that removes introns and joins exons in primary transcript

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22
Q

Lysis occurs when a viral capsid induces ruptrue of endosomal membrane, releasing viral capsid or genome in (enveloped/nonenveloped) viruses

A

Non Enveloped

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23
Q

Endocytosis

A

Process involves invagination and pinching off of small regions of teh cell membrane, resulting in the non-specific internalization of molecules

24
Q

3’ Polyadenylation

A

Stretch of adenylate residues are added to the 3’ end

25
Type of Endocytosis that uses specialized lipid rafts
Caveolin-Mediated Endocytosis
26
Extracellular Spread
Released viruses in extracellular environment travel to new cell, same replication cycle occurs
27
Clathrin-Mediated Endocytosis
* Virion attachment to host cell receptor induces binding of adaptor protein * Adaptor protein bind Clathrin * Clathrin-Coated Pit forms * Dynamin pinch off Clathrin-Coated Pit from host membrane creating a Clathrin coated vesicle * Clathrin basket released from vesicle * Vesicle delivers viral components to endosome * pH of endosome becomes acidic and viral genome is released
28
Intron
Portion of gene that does not code for amino acids
29
Capping
Additon of 7-methylguanosine to the 5' end of RNA
30
Receptor
Structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance and mediates its entry or action into the cell
31
Alternative Splicing
All introns spliced out, only select exons spliced in
32
Latent Period
Time before new infectious virus appears in the medium \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ No extracellular virions detected
33
pH Independent Fusion Proteins
* Fusion protein catalyzes membrane fusion at the cell surface at neutral pH * Viral nucleocapsid is released into the cytoplasm
34
Functions of the 5' Cap
Adds stability to the mRNA Binding of mRNA to ribosomes Marks mRNA as self
35
Permissive Cell
Cell in which a virus is able to replicate
36
Replication of (-) single strand RNA
* (-)ssRNA → RNA Dependent RNA Polymerase → (+) mRNA → Viral Protein * (-)ssRNA → RNA Dependent RNA Polymerase → (+) ssRNA → RNA Dependent RNA Polymerase → (-)ssRNA → Viral genome
37
Non-Permissive Cell
Cells in which a factor or factors necessary to viral replication is not present or one detrimental to viral replication is present
38
Surface Fusion
Enveloped virus fuses with the surface of the host cell, the viral glycoproteins are retained on the cell surface and since they are antigenic the cell becomes a target for immune response
39
Antibody Mediated Penetration
* Virus enters the macrophage by attachment of its spike proteins to the CD13 receptor * Antibodies against spike protein cannot clear the virus from the host - antibodies bind to spike proteins and facilitate entry of virus into host cell through IgG-Fcy receptor
40
Replication of single stranded DNA
* (+)ssDNA Strand → DNA-Dependent DNA Polymerase → dsDNA Intermediate * (-)dsDNA Intermediate → DNA Dependent RNA Polymerase → (+) mRNA → Viral Protein * (-) dsDNA Intermediate → DNA-Dependent DNA Polymerase → (+)ssDNA → Viral Genome
41
Enveloped virions release progeny virions by
Budding
42
Replication of double stranded DNA with Reverse Transcriptase
* dsDNA → (+) ssRNA → RNA dependent DNA polymerase → (-)ssRNA → DNA dependent DNA polymerase → (-) dsDNA → DNA dependent RNA polymerase → (+)mRNA → Viral Protein
43
Enveloped viruses can penetrate the host cell by
Surface Fusion
44
Antibody Dependent Cell Mediated Cytotoxicity
* Antibody binds antigens on the surface of the target cell * Fc receptors on NK cell recognize bound antibody * Cross-linking of Fc receptors signals the NK cell to kill the target cell * Target cell dies by apoptosis
45
T/F: Viruses multiply by division
False \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Viruses do not have the genetic capability to muliply by divison
46
Naked Virions release progeny virions by
Lysis of host cell
47
Uncoating
Release of viral genome in host cell
48
Polycistronic mRNA
mRNA that encodes several polypeptides
49
Some (enveloped/nonenveloped) viruses induce local permeabilization of host endosomal membrane to allow virus capsid penetration into the cytoplasm
Non Enveloped
50
Penetration of the virus into the host cell typically occurs by
Endocytosis
51
pH Dependent Fusion Proteins
* Low pH in endosome promotes fusion of envelope with endosomal membrane * Lysis of nucleocapsid by lysosomal proteases and release of viral genome
52
Replication of double stranded DNA viral genome
* (-)dsDNA Strand → DNA-Dependent RNA Polymerase → (+) RNA → Viral Protein * (+) and (-) dsDNA Strand → DNA-Dependent DNA Polymerase → dsDNA → Viral Genome
53
Constitutive Splicing
Every intron is spliced out and every exon is spliced in
54
Surface membrane fusion of enveloped viruses results in
Antibody-Dependent Cell Mediated Cytotoxicity
55
Assembly and Maturation can take place in
Nucleus, Cytoplasm or Plasma/Cell Membrane
56
Fusion of virus membrane with host endosomal membrane releases the viral genome in (enveloped/nonenveloped) viruses
Enveloped
57
Caps are synthesized from what sources
Host Cell Enzymes Viral Enzymes Cap Snatching - from host mRNA

RUSVM Virology (35 decks)

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