Viruses & Prions Flashcards

1
Q

What are 5 differences between viruses and other microorganisms?

A

They’re non-living, small, an obligate intracellular parasite, contain either DNA or RNA (never both) and have minimal/no enzymes or ribosomes

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2
Q

Capsids are:

A

A protein coat composed of capsomeres surounding virions

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3
Q

The nucleocapsid contains:

A

Genetic information

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4
Q

What is a lipid envelope?

A

An outer layer surrounding the capsid in some viruses

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5
Q

Enveloped viruses are ____ easily inactivated by disinfectants

A

more

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6
Q

Glycoproteins/spikes can be found:

A

Inserted in either the capsid or envelope

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7
Q

The functions of glycoproteins are:

A

Cellular attachment and recognition of binding sites in host cells

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8
Q

Viruses usually have a specific ____ ____

A

host range

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9
Q

The 6 DNA viruses are:

A

Herpesvidrae, Poxviridae, Adenoviridae, Papillomaviridae, Parvoviridae, Hepadnaviridae

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10
Q

What are the three main steps of viral infection?

A
  1. Attachment and penetration into host cell
  2. Replication of the genome
  3. Assembly and release of new virus
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11
Q

What are the two methods of penetration for viral infection?

A

Fusion and pinocytosis

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12
Q

Enveloped viruses usually penetrate the host cell by ____

A

fusion

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13
Q

During penetration, the ____ and/or ____ is removed from the virus

A

envelope, capsule

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14
Q

Virus and its nucleic acids are released into the ____ upon penetration

A

cytoplasm

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15
Q

Describe how DNA viruses replicate in host cells

A
  • Use the host cell’s DNA polymerase to produce viral DNA

- Occurs in nucleus

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16
Q

Describe how RNA viruses replicate in host cells

A
  • Uses own RNA polymerase to produce viral RNA

- Occurs in cytoplasm

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17
Q

Describe how RNA retroviruses replicate in host cells

A
  • Uses own reverse transcriptase in the capsid to produce viral RNA
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18
Q

Replicated viral RNA/DNA have new ____

A

nucleocapsids

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19
Q

If an enveloped virus, the envelope is ____ into the host cell’s plasma membrane and ____

A

inserted, buds

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20
Q

What are the 3 outcomes of infection?

A

Productive/acute, latent, and chronic infection

21
Q

Describe productive/acute infections

A
  • Virus replicates
  • Produces virions
  • Host cell often killed = lytic infection
22
Q

Describe latent infections

A
  • Viral genome persists but doesn’t replicate
  • Provirus
  • Herpes, HIV
23
Q

Describe chronic infections

A
  • Virus replicates without destroying host cell

- Persists for long period of time

24
Q

What are the symptoms of acute infection for chickenpox

A

Fever, itchy rash on trunk and head

25
Q

How is chickenpox transmitted?

A

Direct contact, droplet and airborne if scratched

26
Q

For chickenpox, skin is always present in ____ stages of lesion

A

different

27
Q

Describe latent infection of chickenpox

A

Virus is present in the ganglion, but not replicating, until triggered and reactivates

28
Q

What are 2 complications of chickenpox?

A

Secondary bacterial infection and CNS disease

29
Q

What are 2 methods to prevent chickenpox?

A

Active and passive immunization

30
Q

Describe active immunization

A
  • Live attenuated vaccine

- Highly protective, memory cells produced

31
Q

Describe passive immunizations

A
  • Effective up to 3 days post-exposure

- Mainly for immunocompromised and neonates

32
Q

What is shingles/zoster?

A

Reactivation of chickenpox

33
Q

What are the symptoms of shingles?

A

Skin rash (2-5 weeks) and pain

34
Q

What is a complication of shingles?

A

Post herpetic neuralgia (PHN)

35
Q

Describe PHN

A
  • Pain persists from months to years

- Can cause permanent nerve damage

36
Q

How to treat PHN?

A

Give antiviral (acyclovir) within 48-72 hours

37
Q

Oncogenic virus can transform normal host cells into:

A

Cancer cells

38
Q

What are the 2 methods in viral diagnosis?

A

Polymerase chain reaction (PCR) and culturing

39
Q

What are prions?

A

Misfolded protein that act as infectious agents in susceptible animals

40
Q

____ prion disease is always fatal

A

Human

41
Q

What are the symptoms of human prion disease:

A
  • Ataxia (losing balance)
  • Cortical visual symptoms
  • Dementia
  • Myoclonus: sudden muscle jerks
  • Akinetic mutism: inability to speak
42
Q

What are the 4 antiviral drugs discussed in class?

A

Fuzeon, acyclovir, HAART (Highly active antiretroviral therapy), tamiflu

43
Q

What is the function of fuzeon?

A

Stops fusion of HIV into cells

44
Q

What is the function of acyclovir

A

Stops replication of herpes viruses by interfering with viral DNA polymerase

45
Q

What is the function of HAART?

A

A combination of antiviral drugs for stopping the replication of HIV

46
Q

What is the function of tamiflu?

A

Stops budding/release of influenza

47
Q

For small pox, the skin is always present in ____ stages of lesion

A

identical

48
Q

What are some examples of prion diseases?

A

Mad cow disease, scrapie in sheep, CJD & vCJD in humans