Nature of Human Viruses Flashcards

1
Q

T/F: Virus can’t get through a filter

A

False!
Viruses are filterable agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Are viruses alive?

A

No, they are not considered alive
- they require a living cell to grow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do viruses divide?

A
  • infect a susceptible cell and take over cellular machinery
  • do NOT divide via binary fission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T/F: Antibiotics/antifungals do NOT work on viruses

A

True!
- some antiviral agents are available but most viruses have no effective drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is viruses genetic material?

A

RNA/DNA
- newly made particle= virions spread the virus to new cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is nucleic acid plus capsid called?

A
  • nucleocapsids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the 2 viral capsids and what are their characteristics?

A

Helical capsids in human viruses:
- all negative RNA viruses
- all have enveloped viruses
- most are spaghetti like and not rigid

Icosahedral:
- can be enveloped or naked
- complex structure
- formed from viral capsid proteins with the nucleic acid inside
- can form spontaneously form once a sufficient amount of capsid protein is present
- can withstand stomach acid in some cases
- ex: HPV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

There are 2 types of capsid structures. What are they?

A
  • helical
    which are all enveloped
  • icosahedral
    which can be enveloped or naked
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does it mean for a naked virus?

A
  • no lipid bilayer
  • must be an icosahedral
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are viral envelopes derived from?

A
  • infected cell membranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which type of virus (enveloped or naked) is more labile/easier to disrupt?

A
  • enveloped are more fragile due to easy disruption of lipid bilayer making virus unable to enter
  • naked viruses are more resistant stomach acid, detergents, solvents, heat, and drying agents and can be transferred through oral-fecal route
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How are enveloped viruses are spread?

A
  • respiratory droplets, blood, and sexual contact
  • naked viruses can do all these things plus oral-fecal spread
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is required for viruses to infect?

A
  • proteins need to recognize on the surface of the cell (lipid bilayer)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does a neutralizing antibody do?

A
  • prevent a virus from infecting cell
  • recognize surface proteins on virion:
  • for naked viruses: bind capsid proteins
  • for enveloped viruses: bind envelope glycoproteins embedded in the lipid bilayer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the genome for positive single stranded RNA viruses?

A
  • same sense as mRNA
  • +ssRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the difference of negative sense RNA viruses (-ssRNA)?

A
  • NOT like mRNA
  • must use genome -ssRNA as a template to make mRNA
16
Q

What is the root for family of virus?

A
  • virdae
17
Q

What virus has a segmented genome?

A
  • BOAR viruses:
    bunyavirus, orthomyxovirus, arenavirus, reovirus
18
Q

What is a steady state virus-cell interaction?

A
  • virus does not kill the cell but does produce virus
  • non-cytocidal
  • productive and non-cytocidal
19
Q

What is a lytic-cytocidal virus-cell interaction?

A

2 types:
lytic:
- kills cell, cell death needed to release virus

cytopathic:
- kills cell by making it so sick but not needed to release virus

  • productive and cytocidal
20
Q

What is a latent virus-cell interaction?

A
  • virus infects cells and doesn’t produce any virus but can reactivate
  • ex: any herpesvirus
  • nonproductive and noncytocidal
21
Q

What is syncytial formation?

A
  • infected cell fuses membranes of neighboring cells that are not infected to form large multinucleated cells
  • a way for virus to spread to cells
22
Q

T/F: Cell transformation by viruses is the same as bacterial transformation

A

False!
- if a virus can transform a cell, it’s more likely to cause cancer
- transforming a cell makes them immortal and able to grow on top of each other aka no contact inhibiton

23
Q

What are the viruses that cause cancer?

A
  • EBV (Epstein-Barr Virus)-Burkitt lymphoma, Nasopharyngeal carcinoma, oral hairy leukoplakia (in HIV infections)
  • HPV (Human Papilloma Virus) – Cervical, Anal, and Oropharynx
  • Human Herpes Virus 8-Kaposi’s Sarcoma (in HIV infections, immunocompromised)
  • HTLV (Human T cell lymphotropic virus) Adult T-cell leukemia and lymphoma
  • HBV (Hepatitis B virus)-Hepatocellular carcinoma
  • HCV (Hepatitis C Virus)-Hepatocellular carcinoma
24
Q

All DNA viruses are….

A

icosahedral

25
Q

All -ssRNA viruses are (except coronavirus)…

A

helical

26
Q

What viruses are linear ssDNA?

A

Parvovirus

27
Q

What viruses are linear dsDNA?

A

Adenovirus, Herpesvirus, and Poxvirus

28
Q

What viruses are circular dsDNA?

A

Papillomavirus and Polyomavirus

29
Q

What viruses are circular mostly ds but small part is ssDNA?

A

Hepadnavirus

30
Q

What viruses are +ssRNA?

A

Hepevirus, Picornavirus, Calicivirus, Togavirus, Coronavirus, Flavivirus, and Retrovirus
Retrovirus have +ssRNA but incorporate 2 strands of same RNA into virion

31
Q

What viruses are -ssRNA?

A

Filovirus, Paramyxovirus, and Rhabdovirus

32
Q

What viruses are segmented -ssRNA?

A

Arenavrius, Bunyavirus, and Orthomyxovirus

33
Q

What viruses are segmented dsRNA?

A

Reovirus

34
Q

What viruses are circular -ssRNA?

A

Deltavirus (HDV) but required Hep B virus to replicate