Quiz 1 Flashcards
What is obligatory viremia?
need for viruses to travel in blood; targeted more easily by vaccines via antibodies
what is plus-stranded RNA?
messenger RNA (positive stranded)
icosohedral symmetry has ___ faces
20
how do antibodies neutralize viruses?
binds to virion protein required for attachment to host. Therefore virus can’t get in.
incclusion bodies are:
visible areas on EM where viruses are being assembled and packaged into virions. area of cell helps classify virus
plaque
single virus dropped onto cell, spreads and causes cells to lyse and creates zone of death.
syncytia
single cell defined by plasma membrane that contains more than one nucleus.
Describe the series of steps in replication of polio virus:
1) +-stranded RNA enters cytoplasm
2) host machinery used for translation into polyprotein
3) cleavage into functional proteins & viral RNA polymerase
4) polymerase makes -RNA from +RNA.
5) -RNA = template for more +RNA
What are synonyms for asymptomatic infection?
Subclinical, inapparent or silent infection
the picornavirus group has what
a) symmetry
b) nucleic acid genome
c) 5 examples are:
a) icosahedral
b) single + RNA
c) Polio, coxsackie, echo, rhinoviruses, hepatitis A
reovirus group has what
a) symmetry
b) nucleic acid genome
c) example
a) icosahedral
b) multiple molecules of double-stranded RNA
c) rotaviruses
the two families of unenveloped RNA viruses are
picornavirus; reovirus
the 6 families of enveloped RNA viruses are:
orthomyxovirus; paramyxovirus; rhabdovirus; coronavirus; togavirus; retrovirus
rhabdovirus & paramyxovirus have what
a) symmetry
b) nucleic acid genome
a) helical
b) single negative RNA
What are four examples of the enveloped RNA virus family paramyxovirus
parainfluenza; respiratory syncytial; measles; mumps
Orthomyxovirus has what
a) symmetry
b) nucleic acid genome
c) example
a) helical
b) multiple molecules of negative RNA
c) influenza
most enveloped RNA viruses have what symmetry?
helical
What is the a) symmetry and b) nucleic acid genome of coronaviruses?
a) helical
b) single + RNA
ex: SARS
Togaviruses have what
a) symmetry
b) nucleic acid genome
c) example
a) icosahedral
b) single + RNA
c) equine encephalitis
retroviruses have what
a) symmetry
b) nucleic acid genome
c) example
a) uncertain
b) 2 identical + RNA
c) HIV-1; various tumor viruses
the three families of unenveloped DNA viruses are:
parvovirus; papovavirus; adenovirus
what is the nucleocapsid symmetry of the unenveloped DNA viruses parvovirus, papvavirus, and adenovirus?
icosahedral
what are two viruses with a single molecule of circular double stranded DNA?
papovavirus, adenovirus
what is the nucleic acid genome of parvovirus?
single molecule of single stranded DNA
ex: B-19
herpesvirus have what
a) symmetry
b) nucleic acid genome
c) example
a) icosahedral
b) single molecule double-stranded DNA
c) herpes simplex, varicella-zoster, cytomegalovirus, EB virus