exam three (viruses) Flashcards
viruses are ____
aceullular
a virus particle is called ___ and can be DNA or RNA
virion
viruses can have a protective ____ from host cell (takes piece of host when it buds)
envelop e
viruses can exist outside or inside of a cell; where do they need to be to replicate
inside a cell
viruses can use all machinery or only some machinery from ____ (energy, metabolism, etc.)
host
viruses have a ____ ____ inside a capsid
nucleic acid (RNA or DNA)
nucleic acid and capsid together is called
nucleocapsid
an enveloped virus has host cell proteins and _____ proteins (has also a protective lipid bilayer)
virus
-the shape of virus is its _
symmetry
in a _____ virus the nucleic acid and structure around it are twisted
helical
polyhedron with 20 triangle faces
icosahedral
a _____ virus shape doesn’t fit into helical or icosohedral
complex
nakes viruses do not need
envelope
most of the envelope is made up of _____ constituents (but has viral proteins in envelope to be able to attach)
host
the genes of a DNA virus can be either ___ or ____
linear or cirular
The genes of an RNA virus can be ___ , ____ or ___
linear, circular or segmented
segmented RNA viruses have more than one piece of ___; can change readily
RNA
class I virus
double strand DNA
class II virus
single stranded DNA
class III virus
double stranded RNA
single stranded RNA class (IV)
is a plus or sense strand
the plus strand can be translated into ___
protein
single stranded RNA class (V)
minus or antisense strand
the antisense strand has to be repliacted before it can make ____
proteins
RNA class (VI)
retrovirus
DNA double stranded, gapped, reverse transcriptase
class VII
when the virus integrated into target cell it has to ____ its genome and make __ ____ to send off particles
replicate; virus proteins
dsDNA virus does the exact same replication as humans which means
transcription, translation into proteins
an ssDNA virus makes ____ as an intermediate
dsDNA
once the ssDNA virus has made its intermediate it makes ___ and ____
mRNA (translated into protein) and ssDNA (this is the genome of the virus)
the double stranded RNA makes a _____ intermediate (its necessary)
ssRNA
the double stranded RNA makes a _____ intermediate other than ssRNA
mRNA
the antisense strand of RNA makes an mRNA intermediate that can then be made into RNA
a retrovirus (ssRNA) becomes _____ to replacte
dsDNA
the retrovirus end products from dsDNA are ____ and ___
ssRNA and mRNA
hepadnaviruses (liver) they are ___ dsDNA (gapped) viruses makes ssRNA and mRNA
partial
use host to repliacte, translate genomes
DNA viruses
need to bring their own polymerases
RNA viruses
five steps of replication cycle
- attachmemnt (adsorption)
- penetration (entry)
- synthesis
- assembly
- release (can bud or lyse)
viruses that infect prokaryotic cells
bacteriophage
a virulent phage ____; does lytic cycle
lysis
a temperate phage is _____
lysogenic
lysogenic conversion means virus brings something new to ____
genome (can be a virulence factor)
from the moment of infection to lysis of bacterium from T4 phage is ___ min.
25
Adsorption of the T4 phage has a very specific ____
tropism
tropism is very specific towards different __ ___ ___ to attach
cell envelope components
t4 likes ___ of E. Coli
LPS
__ __ of T4 contract when it makes contact with LPS to pentrate and inject nucleic acid
tail fibers
the baseplate of the t4 contact membrane in what phase
penetration or entry
lysozyme dissolves
peptidoglycan
the T4 phage releases ____ during entry, then injects DNA (without this; dna cannot enter)
lysozyme (allows it to get all the way through)
DNA cannot get through ___ ___ without lysozyme
inner membrane
DNA makes early mRNA, middle and late so that it can make
early, middle and late proteins
the early mRNA’s ____ host cell machinery; degrade the host cell (taking immune defenses out of play)
commandeering
the middle and late mRNA’s and late mRNA’s focus on _____ sturctural proteins, phage assembly
phage
late mRNA’s mostly but not entirely focus on __ ___
cell lysis
___ is needed from bacterial cell to put DNA into head
ATP
using phages to clear bacterial infections is called
phage therapy
phages cannot infect ____
humans
phage therapy is restricted because of?
very very specific tropism
eukaryotic viruses have similar stages of infection but what are the two differences
entire virion enters cell
eukaryotes have nucleus and organelles
the eukaryotic viruses are looking for ____ or ____ as tropism
receptors or adhesions
eukaryotic virus
the viruses use ___ ____ to attach and find target on host cell
spike proteins
HIV has gp120 and gp41 that has tropism for immune cells; if a person does not express one of them (CCR5) then it cannot infect the human.
CD4 and CCR5 (need both to be infected)
the host cell and enveloped virus cell will fuse and allow ____ to be put into cell
nucleocapsid
eukaryotic
the non-enveloped virus will attach to receptor and be taken in by ___ __ ___
receptor mediated endocytosis
the translation and replication of a eukaryotic virus can happen where
in nucleus or cytoplasm
the virus has to deal with ____ in eukaryotic cell (nucleus, ER, ribosomes); has to take over machinery to do that
organelles
HIV is a ssRNA ____ and has to make dsDNA to be functional so they bring their own __ ___
retrovirus; reverse transcriptase
____ happens in a lot of envelope virus
budding (virus factories; does not kill cell )
naked viruses typically ____ cell
lyse
viruses without a doubt ____ cell function
disrupts
the virus can cause death of cell or _____
cytocidal
a virus that lasts 1-2 weeks
acute infection
a virus that lasts years and is never dormant
chronic
an acute infection but then the virus stops replicating but is living in cell is a ___ virus; chickenpox and herpes simplex
latent
___ has all three stages of infection; acute then latent; reemerges as chronic infection
HIV
Hepatitis C is ____
chronic
viral infections can lead to cancer, common of ____
HPV
virus will bring ____ or turns on ___ __ in your own cell
oncogene; proto-oncogene
plant viruses are most ___ viruses
RNA
first studied plant RNA virus
tobacco mosaic virus
new and really large viruses typically effect
protozoa, amoeba or fungi
pithovirus sibericum is the ____ virus
giant
a virus that can infect insects
baculovirus
most viruses that infect archaeal are __DNA and have unusual morphologies
dsDNA
ATV virus grows ___ at high temp to infect archaea
tail
infectious circular pieces of ssRNA; only infect plants
viroids
viroids do not encode ___ and take no proteins from plant; only use plant to replicate
proteins
satellite viruses require ___ ___ to infect plant (viroids)
helper virus
proteinaceous infectious partice; abnormally folded and attach to normally folded proteins and cause normal ones to ____; this is the function of a
misfold; prion
misfolded proteins ____ together and cause cell to misfunction
aggregate
bovine spongifrom encephalopathy (mad cow disease) is caused by ____ and misfolded proteins
in humans its called creutzfeldt-jakob disease
prions