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81 Cards in this Set
- Front
- Back
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DNA virus genome replication goes ___->___
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DNA-->DNA
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Retrovirus genome replication goes ___--> ___
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RNA --> DNA
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Pararetrovirus genome replication goes __--> ___
(ex:?) |
DNA -->RNA-->DNA
(hepadnavirus) |
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DNA replication begins at ___ sites
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origin
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DNA dependent synthesis requires a ____ for initiation of replication.
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primer
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True or False
Replication is semi conservative |
True
Each product has one parental and one daughter strand |
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What happens during DNA virus replication?
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Proteins are hijacked from the host machinery
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During which phase of the cell cycle does virus replication with host DNA take place?
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S phase
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True or False
Viruses cannot induce S phase in their host |
False - the y can
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What phase of the cell cycle do cells grow?
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G1
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At what point does a cell decide whether to continue
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R or restriction point
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g1 r s g2 m
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Just look at it
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dsDNA viruses are ___ and ___.
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linear and circular
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Family names of dsDNA viruses
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polyoma, papillonma, adeno, hepadna, herpes, Irido, pox
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dsDNA genome (AGAIN!!) =
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polyomaviridae, adenoviridae, herpesviridae, poxviridae
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Polymerases in dsDNA are supplied by ____ and transcription is carried out by ___.
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virus or cell
cellular RNA polymerases |
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in dsDNA viral replication who supplies primer other enzymes for elongation.
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The host
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Circular viral DNA is packaged with what?
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Histones
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True or False
In dsDNA, replication is unidirectional |
False it is bi-directional
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What is used to relieve supercoiling in circular DNA and also aids in untangling?
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topoisomerase I or II for supercoils
or topo II for separation |
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Adenovirus has a ___ genome
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linear
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Adenovirus genome replication uses a ____ and ____.
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protein primer and strand displacement
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The protein in adenovirus is attached to a ____ in order to generate a primer.
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C-residue
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How many daughter molecules are made during adenovirus replication?
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2
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True or False
The primer used during adenovirus replication is an RNA molecule. |
False- it's a protein that base pairs with the terminal on the viral genme
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Why does a displaced strand in the replication of adenovirus circulize?
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Due to inverted terminal repeats
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The circular displaced strand in the adenovirus genome is used for what?
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To act as a primer and make another molecule (has panhandle primer)
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Name some ssDNA viruses?
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Parvo and Circo
Note: they are very small |
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True or False
in ssDNA viral replication there is a dsDNA intermediate |
True, dsDNA is the template used for replication
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_____ virions are transported to the nucleus via ____
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Parvovirus, nuclear pore
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Physical characteristic of parvovirus?
Why important? |
Looks like a barbell
Barbell is important for replication, pairing there acts like a primer |
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Where is parvovirus' ssDNA genome released?
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the nucleus
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True or False
Parvovirus cannot induce S phase |
True
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_______ in parvovirus prime replication start
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termminal repeat sequences
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Write down the steps of parvovirus replication
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http://nature.berkeley.edu/~elyons/X142/data/files/DNAreplicationandproteinexpression.pdf
go here |
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In parvovirus who brings the nicking enzyme?
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the virus
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What is the overall end result of parvovirus replication?
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one full length ssDNA and one intermediat dsDNA used to return to step 2
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Retroviruses are a _____ genome that involve a ____.
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+ssRNA
DNA intermediated |
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Characteristics of retrovirus replication?
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-virion has two copie of +ssRNA genome
-nucleocapsid protein is bound to RNA -Virion contains reverse transcriptase |
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Draw the retrovirus replication cycle
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http://nature.berkeley.edu/~elyons/X142/data/files/DNAreplicationandproteinexpression.pdf
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In reverse transcription what serves as a primer?
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tRNA
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In retroviral transcription what does RNase H do?
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Digests RNA/DNA complex, also removes tRNA at end
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where does tRNA come from in retrovirus transcription?
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comes from last host
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RT in rever.T recognizes what to begin transcription?
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pbs
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Why are LTR's important?
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Are important for integration and regulation of transcription once dsDNA is integrated into the host genome
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True or False
In integration or retrovirus dsDNA, the provirus remains for life of cell and is inherently mutagenic |
True
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Hepadnaviruses are a ____ genome that involve a ____ intermediate
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dsDNA
RNA |
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How does a hepadnavirus enter the cell?
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via direct membrane fusion
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True or False
The Hepadnavirus genome is never integrated into the host genome |
True
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In regards to hepadnavirus, when does reverse transcription take place?
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Before the new virion exits the cell
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In regards to hepadnavirus, where does the open circular DNA goe to get "repaired"?
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virus
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What kind of structure does hepadnavirus have?
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Open circular dsDNA
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Polymerase is added to the ____ end in the hepadnavirus.
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-5' end
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Which end of DNA in hepadnavirus is capped?
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+5'
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In the hepadnavirus which strand is full length and which is incomplete?
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+ strand is incomplete, and - is full
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In regards to hepadnavirus,
how many mRNA's are produced and where? |
5-all in the nucleus, 1 is the pregenomic RNA
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Hepadnavirus reverse transcriptase priming uses ____
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protein priming
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Hepadnavirus RT acts as the protein primer therough a conserved ____ in terminal protein region.
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tyrosine
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Primer in HIV:
Primer in Hep: |
tRNA
tyrosine |
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In regards to hepadnavirus, RNA/CAP primes _____.
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+ strand RNA synthesis
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eukaryotic mRNAs are processed from _____ before eport from the nucleus
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precursor
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Almost all eukaryotic mRNA's are ___.
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monocistronic- one reading frame codes for one genome
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What cap structure is most common in viral and mammalian mRNA
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m(^7)GpppN
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True or False
Virus particles are often polycistronic |
True
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Translation of many (+)ssRNA viruses is initiated at ____
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5' cap structure
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in (+)ssRNA
expression of 5' proximal: expression of 3' via - |
host mRNA's
subgenomic mRNAS |
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Picornavirus is capable of ____expression
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polyprotein
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Polyprotein processed by which proteases?
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2A^(pro) and 3C^(pro)
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True or False
A monocistronics RNA can encode multiple proteins |
True
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Purpose of suppression of termination
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to generate fusion proteins with extended carboxy termini
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Retroviruses express ___ and ___ genes to help supression of termination
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gag and pol
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Leaky scanning enables translation of ___
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nested genes
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Give examples of viruses with overlapping reading frames.
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Alpha viruses, influenza, retroviruses, and SV40
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Ribosomes usually terminate at ___.
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UAG
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Where will a tRNA shift back in ribsomal frameshifting?
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at a shifty heptanucleotide AAAUUUA
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Ribosomes can skip over hairpin structures via ____.
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ribosome shunting
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If a virus lacks a cap, what can be used instead?
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IRES- internal ribosome entry sites
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Type I IRES ---
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entero and rhinovirus
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Type II IRES
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CARDIO AND APTHOVIRUSES
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Type III IRES
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hepatitis C virus
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The 3' ends of viral RNA's may interact with the 5' end and form ___.
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pseudoknots- a way of getting around knots
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