Micro - Virology (Viral Basics) & Prions Flashcards Preview

FA - Microbiology > Micro - Virology (Viral Basics) & Prions > Flashcards

Flashcards in Micro - Virology (Viral Basics) & Prions Deck (35)
Loading flashcards...
1
Q

Name, draw, and label the 3 progressions of general features for viral structure.

A

(1) Naked virus with icosahedral capsid - nucleic acid, capsid (2) Envelope virus with icosahedral capsid - nucleic acid, capsid, lipid bilayer, surface protein (3) Enveloped virus with helical capsid - helical capsule with nucleic acid inside, lipid bilary, surface protein; See p. 153 in First Aid for drawing and labels

2
Q

What are 4 processes in viral genetics?

A

(1) Recombination (2) Reassortment (3) Complementation (4) Phenotypic mixing

3
Q

What is recombination?

A

Exchange of gene between 2 chromosomes by crossing over within regions of significant base sequence homology

4
Q

What is reassortment? What virus and consequences should you associate with this process?

A

When viruses with segmented genomes (e.g., influenza virus) exchange segments; High-frequency recombination. Cause of worldwide influenza pandemics

5
Q

What is complementation?

A

When 1 or 2 viruses that infect the cell has a mutation that results in a nonfunctional protein. The nonmutated virus “complements” the mutated one by making a functional protein that serves both viruses

6
Q

What is phenotypic mixing?

A

Occurs with simultaneous infection of a cell with 2 viruses. Genome of virus A can be partially or completely coated (forming pseudovirion) with surface proteins of virus B. Type B protein coat determines the tropism (infectivity) of the hybrid virus. However, the progeny from this infection have a type A coat that is encoded by its type A genetic material.

7
Q

What are the different kinds of viral vaccines?

A

(1) Live attenuated (2) Killed (3) Recombinant

8
Q

What kind of immunity do live attenuated vaccines induce? What is a potential side effect?

A

Induce humoral and cell-mediated immunity, but have reverted to virulence on rare occasions

9
Q

Contrast live attenuated and killed/inactivated vaccines in terms of immunity induced and risks posed.

A

LIVE ATTENUATED - Induce humoral and cell-mediated immunity, but have reverted to virulence on rare occasions; KILLED/INACTIVATED - Induce only humoral immunity but are stable

10
Q

What are examples of live attenuated vaccines?

A

(1) Smallpox (2) Yellow fever (3) Chickenpox (VZV) (4) Sabin’s polio virus (5) MMR (6) Influenza (intransal); LIVE attenuated - SMALLpox, YELLOW fever, CHICKENpox (vzv), SABIN’S polio virus, MMR, Influenza (IntraNasal) = Think: “LIVE! one night only! see SMALL YELLOW CHICKENS get vaccinated with SABIN’s and MMR! It’s INcredible!”

11
Q

What are examples of killed vaccines?

A

(1) Rabies (2) Influenza (injected) (3) Salk Polio (4) HAV vaccines; Think: “RIP Always, salK = Killer”

12
Q

What are examples of recombinant vaccines? Give specifics on antigens/types as they apply.

A

(1) HBV (antigen = recombinant HBsAg) (2) HPV (types 6, 11, 16, and 18)

13
Q

What is a live attenuated vaccine that can be given to HIV-positive patients, and in what context?

A

MMR = measles, mumps, rubella (live attenuated vaccine that can be given to HIV-positive patients) who do not show signs of immunodeficiency)

14
Q

What are 2 advantages of live attenuated vaccines? In what patient population(s) is it dangerous to give live vaccines?

A

(1) No booster needed for live attenuated vaccines (2) Cellular and humoral immunity (unlike only humoral in Killed vaccines); Immunocompromised patients & their close contacts

15
Q

What kind of nucleic acid material do nearly all DNA viruses have? What is the exception, and what is its nucleic acid material?

A

dsDNA, except Parvoviridae = ssDNA; Think: “Parvus = small” and “all are dsDNA (like our cells), except ‘part-of-a-virus’ (parvovirus is ssDNA”

16
Q

What is the shape/form of nucleic acid material in nearly all nearly DNA viruses? What are the exceptions, and what is their shape/form of nucleic acid material?

A

Linear, except papilloma-, polyoma-, and hepadnaviruses = circular

17
Q

What kind of nucleic acid material do nearly all RNA viruses have? What is the exception, and what is its nucleic acid material?

A

ssRNA, except Revoiridae = dsRNA; all are ssRna (like our rna), except (REOvirus) = dsRNA; Think: “REpeatO-virus”

18
Q

What are the positive-stranded RNA viruses?

A

(1) Retrovirus (2) Togavirus (3) Flavivirus (4) Coronavirus (5) Hepevirus (6) Calcivirus (7) Picornavirus; Think: “i went to a RETRO TOGA party where i drank FLAVored CORONA and ate HIPPY CALIfornia PICkles.”

19
Q

Which purified nucleic acids are infectious?

A

INFECTIOUS: Purified nucleic acids of most dsDNA (except poxviruses and HBV) and (+) strand ssRNA (like mRNA) viruses

20
Q

Which naked nucleic acids are not infectious, and why?

A

NON-INFECTIOUS: Naked nucleic acids of (-) strand ssRNA and dsRNA viruses, because they require polymerases contained in complete virion

21
Q

Where do nearly all DNA viruses replicate? What is the exception?

A

All replicate in the nucleus (except poxvirus)

22
Q

Where do nearly all RNA viruses replicate? What are the exceptions?

A

All replicate in the cytoplasm (except influenza virus and retroviruses)

23
Q

What are naked viruses? What are examples of naked viruses?

A

Nonenveloped viruses; (1) Papillomavirus (2) Adenovirus (3) Picornavirus (4) Polyomavirus (5) Calcivirus (6) Parvovirus (7) Reovirus (8) Hepevirus; Think: “give PAPP smears and CPR to a NAKED HEPpy (hippy), DNA = PAPP, RNA = CPR, & hepevirus”

24
Q

How do enveloped viruses generally acquire their envelopes? What is the exception to this, and how does it acquire its envelope?

A

Generally, enveloped viruses acquire their envelopes from plasma membrane when they exit from cell; Exceptions include herpesviruses, which acquire envelops from nuclear membrane

25
Q

What are the 5 general rules of DNA viruses, and their exceptions?

A

(1) are HHAPPPy viruses (Hepadna, Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma) (2) are double stranded (except Parvo = single stranded) (3) are linear (except Papilloma & Polyoma = circular, supercoiled & Hepadna = circular, incomplete) (4) are icosahedral (except pox = complex) (5) replicate in the nucleus (except pox = carries own DNA-dependent RNA polymerase)

26
Q

What are the DNA viruses?

A

Hepadna, Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma; Think: “DNA viruses are HHAPPPy viruses”

27
Q

Are nearly all DNA viruses double stranded or single stranded? What is the exception to this general rule?

A

Double stranded; Except Parvo = single stranded

28
Q

What shape/form is the nucleic material in nearly all DNA viruses? What are the exceptions to this general rule?

A

Linear; Except Papilloma & Polyoma (circular, supercoiled) & Hepadna (circular, incomplete)

29
Q

What shape of caspid do nearly all DNA viruses have? What is the exception?

A

Icosahedral; Except pox = complex

30
Q

Where do nearly all DNA viruses replicate? What is the exception?

A

Replicate in the nucleus; Except pox (carries own DNA-dependent RNA polymerase)

31
Q

What causes prion diseases?

A

Prion diseases are caused by the conversion of a normal cellular protein termed prion protein (PrP^c) to a Beta-pleated form (PrP^sc), which is transmissible

32
Q

Again, what causes prion disease? Is it transmissible?

A

Prion diseases are caused by the conversion of a normal cellular protein termed prion protein (PrP^c) to a Beta-pleated form (PrP^sc), which is transmissible

33
Q

What role does PrP^sc directly play in prion disease?

A

PrP^SC resists degradation and facilitates the conversion of still more PrP^c to PrP^sc

34
Q

What conditions result from the accumulation of PrP^sc?

A

Accumulation of PrP^sc results in spongiform encephalopathy and dementia, ataxia, and death

35
Q

What are the different forms of prion disease? Give an example of each form.

A

It can be (1) Sporadic (Creutzfeldt-Jakob disease – rapidly progressive dementia), (2) Inherited (Gerstmann-Straussler-Scheinker syndrome), or (3) Acquired (kuru)

Decks in FA - Microbiology Class (43):