L18 Symmetry, genome, shape and size Flashcards
what are viruses?
acellular microorganisms that require a host to survive
obligate intracellular parasites
aspects of viruses that make them living
have self-replicating genome
produce offspring
encode enzymes
what does a viruses ability to encode enzymes do
allows it to manipulate the metabolism of the host
what aspects of viruses make it non-living
acellular
obligatory dependence on host
do not have their own metabolism
what aspects of viruses make it non-living
acellular
obligatory dependence on host
do not have their own metabolism
general structure of a virion
nucleocapsid (nucleic acid genome + protein coat)
name of the protein coat
capsid
what is the third components that is sometimes present in virions
lipid envelope
what is the capsid comprised of
multiple units of protein building blocks
-protomers
symmetry of protomers
helical
icosahedral
complex
describe a helical structure
a helix (spring) similar to the nucleic acid
example of virus with helical symmetry
tobacco mosaic virus
examples of enveloped helical viruses
influenza
covid
describe icosahedral symmetry
icosahedral (20 face polyhedron)
each face is an equilateral triangle
what happen within each triangular face of viruses with icosahedral symmetry
protomers further arrange into units of 5-6 to form capsomers
examples of non-enveloped viruses with icosahedral symmetry
poliovirus
adenovirus
papillomavirus
examples of enveloped viruses with icosahedral symmetry
herpes simplex virus
what is binal symmetry
when the capsid is separated into two parts;
icosahedral head
helical tail
example of a virus with binal symmetry
bacteriophage
what is complex symmetry
when the virus capsid is not either icosahedral or helical
example of virus with complex symmetry
pox virus
structure of pox virus
envelope
inner membrane
core with nucleic acid
lateral body
components of the viral genome
nucleic acid: RNA and DNA
4000->1 million nucleotides
possible structures of a virus genome
linear
circular
segemented
example of a virus with a segmented genome
influenza virus
example of a virus with a circular genome
simian virus
example of a virus with a linear genome
pox virus, coronavirus
4 configurations of the viral genome
single-stranded DNA
double-stranded DNA
single-stranded RNA
double-stranded RNA
what two configuration are common and which are rare
dsDNA and dsRNA common
ssDNA and ssRNA rare
example of virus with ssDNA
Parvovirus
example of virus with dsDNA
poxvirus
bacteriophage
example of virus with dsRNA
influenza
coronavirus
example of viruses with ssRNA genome
reovirus
what is ssRNA divided into
positive sense (plus strand) negative sense (negative strand)
example of positive sense ssRNA genome
zika virus
corona virus
example of negative sense ssRNA viruses
influenza
shapes of viruses
rod brick bullet filament crystal moon-landing shuttle crown
size range of viruses
10nm-400nm
what is the largest virus known
mimivirus
