Virology 2

Question 1

Name of whole virus particle?

Answer 1

Virion

Question 2

What is the process of viral life?

Answer 2

Attachment
Penetration
Uncoating
Transcription & translation of viral proteins
Genome replication
Assembly
Maturation
Release

Question 3

What is the name of the receptor used by flu virus?

Answer 3

Sialic acid, which is a component of plasma membrane gangliosides

Question 4

Three types of penetration; they are? Most common?

Answer 4

Viral translocation - not much known about, only naked.

Surface fusion (from without) - enveloped viruses only; pH independent

Receptor mediated endocytosis - naked or enveloped, MOST COMMON, pH dependent

Question 5

How does release of naked viruses differ from that of enveloped… any exceptions?

Answer 5

Naked happens just because the cell bursts. The naked virus assembles, and during replicaiton of the genome the cell isn’t functioning well, and eventually it lyses.

Enveloped viruses assemble associated to a membrane, and the glycoprotein spikes attach to the membrane and the bud forms there. The plasma membrane then invaginates and the virus buds with its new enveloped made from the host cell plasma membrane.

Exception: some enveloped viruses exit naked because they form a vesicle by budding on intracellular machinery membranes instead of external plasma membranes, and then the vesicle fuses with the external plasma membrane and the virus exits uncoated.

Question 6

Which viruses are spread by insects?

Answer 6

Yellow fever
Malaria
Dengue

Question 7

Most common route of viral ifnection?

Answer 7

Resp tract

Question 8

What are the immune defecnces of the RT?

Answer 8

Secretory IgA
Alveolar macrophages
Tonsillar lymphoid tissue
Ciliary escalator
Mucus

Question 9

M cells, where are they and waht’s their significance?

Answer 9

Scattered among peyer’s patches and lymphoid aggregates

Antigen uptake and presentation to initiate immune response

Used by pathogens for entry e.g. coronavirus, HIV

Question 10

How does flu attach?

Answer 10

Haemagluttinin

Question 11

How does flu detach?

Answer 11

Neuraminidase

Question 12

What is the genome of flu?

Answer 12

ssRNA(-)

Question 13

How does rabies disseminate?

Answer 13

Nerves

Question 14

Very long incubation period w/ years before sx?

Answer 14

Insidious

Question 15

Infection with no symptoms but may be transmitted?

Answer 15

Subclinical (carrier state)

Question 16

Persists beyond acute onset and may be reactivated

Answer 16

Latent

Question 17

Infectious agents persist with symptosm and slow to resovlve

Answer 17

Chronic

Question 18

Rapid onset, short lived

Answer 18

Acute

Question 19

What is cell rounding?

Answer 19

Cytopathic effect of virus

Question 20

What are the cytopathic effects?

Answer 20

Cell rounding
Formation of inclusion bodies
Syncitia formation
Cell fusion
Inhibition of protein synthesis
Inhibition of DNA/mRNA synthesis and degradation

Then transformation or cell death

Question 21

Damage to cells by viruses can be…

Answer 21

direct e.g. cell death

indirect e.g. immunosuppression

Question 22

Which chemical is produced in abundance in virally infected tissue and why do we care?

Answer 22

NO

It’s produced during inflammation from L-argnine by iNOS, and inhibits viral replication.

Its damaging to the tissue at high concentrations

Question 23

What are free radicals?

Answer 23

Superoxide (O2-) and nitric oxide (.NO)

Question 24

Why does measles virus cause immunosuppresion?

Answer 24

Infects DCs and macrophages causing their destruction

Question 25

Why does EBV cause immunosuppresion?

Answer 25

Infects B-cells causng a latent infection

Question 26

Which virus is associated with a cancer and which type?

Answer 26

EBV

B-cell lymphoma in IC patients