Intro Virology Flashcards
How many nm does virus range
20-300nm
What two things does a virus contain and sometimes a third?
nucleic acid
protein sheath
lipid envelope
role of protein sheath
carry around nucleic acids
how virus reproduce
obligate intracellular parasites
location of capsid
outer protein sheath
roleof capsid
predominant structure
three main capsid “shapes”
icosahedral (roughly spherical)
helical (cylindrical)
complex (combo of the upper two)
composition of capsid
collection of individual subunits
Icosahedral viruses are composed of repeating subunits called _____, which are composed of ___ individual protein structures, each called a _____.
capsomeres, 5-6, protomer
when a lipid membrane from the host is pinched off
enveloped
when a virus is considered naked,
only a capsid is surrounding the genetic material
places the envelope can come from
plasma membrane, nuclear membrane and cytoplasmic membranes
structure to help viruses attach to host
glycoproteins ‘spikes or envelops proteins’
layer between proteins and capsid
tegument or matrix protein
role of tegument
attach envelope to capsid and delivering viral genetic material/replication enzymes into cells
Types of viruses
DNA, ssDNA, dsDNA
RNA, ssRNA, dsRNA, ssRNA(-), ssRNA (+)
Sense refers to
reading (translation) direction of genetic material
Positive sense
directly translated into viral proteins (5’ to 3’), pracitcally mRNA
Negative-sense
complementary strand needed
glycoproteins can be on
capsid or envelope
a virus can use a _____ to enter a cell
co-receptor
name of period when virus injects genetic material
eclipse phase
antibodies work only before
eclipse phase
two ways enveloped viruses enter
direct fusion
viropexis
viropexis
essentially receptor mediated endocytosis
envelope fuses with the endosomal vesicle not the plasma directly
viropexis
what causes vesicles to open
low pH
enters through viropexis but disrupt the endosomal vesicle
naked capsids
series of viral genomes
concatemer
if replication is done in the cytoplasm, virus must bring its own
enzymes
protiens in different batches, expressing their genome in phases, each induced by the proceeding protein products
complex expression
name of phase where it remains dormant in its circular configuration within nucleus
latent phase
name of phase when replicating
lytic phase
RNA (+) reproduce in the
cytoplasm
RNA (-) needs to
bring own polymerase, works either in cytoplasm or nucleus
Retroviruses can
form DNA from RNA
Encapsidation
step wise/regulated assembly of genetic material and capsid protein
Ex of bugs that use direct fusion
HIV-1, herpesvirus, paramyxovirues
Ex of bugs that use viropexis
influenza, rubella, rabies
