Quiz 1 Flashcards
In virology, what is meant by the term non-structural protein?
Non-structural proteins are not part of the virus particle and are found only within the infected cell.
What two functions are associated with the proteins encoded by any given virus?
- capsid protein that is used for genome protection
2. a nucleic acid polymerase or modifier subunit which re-targets a cellular polymerase. Used for genome replication.
What two kinds of macromolecule do extracellular virus particles invariably contain?
Nucleic acid plus protein
In the ‘NdNp’ notation, what is the designation of a reverse transcriptase activity?
RdDp
In virology, what specifically is meant by the term ‘structural protein’
A protein which is part of the virus particle
What are viruses functionally?
- Obligate intracellular parasites
- Viruses just don’t use the machinery of the host cell, they actively subvert it for their own ends. (Don’t use hosts machinery- viruses hijack the plane and reprogram to make virus particles/fly somewhere else)
- No viral genome encodes rRNA- (Don’t make proteins-depend on protein producing ribosome in host cell)
What do SOME viruses have structurally?
-Some have a lipid envelope or contain lipids within the particle.
What are the different forms of nucleic acid that can be contained in virus particles?
- RNA or DNA
- circular (DNA) or linear (RNA or DNA)
- Single stranded (ss) or double-stranded (ds)
Where are viruses found?
EVERYWHERE
- both prokaryotes and eukaryotes
- bacteria and Archaea- numerous types of phages
- animals
- plants
- fungi
What is the virus program called?
Infection cycle
What is the objective of a virus program?
is to produce Viral Progeny (make more than what you put in)
Viral infection as a program of events
-right thing has to happen at the right place and time (temporal and spatial compartments)
How do viruses push the envelope of what is possible in the cell?
There able to start translation with other codons
How are viruses genetically composed?
typically, little, or no junk in their genomes (everything is functional)
What else can viruses encode instead of the minimum?
-membrane spanning proteins called SPIKES
(applies to enveloped viruses only)
-proteins that are not part of the virus particle and are found only within infected cells called NON-STRUCTURAL PROTEINS
In the ‘NdNp’ notation, what is the designation of the polymerase that our cells are full of and transcribes DNA to RNA?
DdRp
In the ‘NdNp’ notation, what is the designation of the two most common polymerases?
DdRp
DdDp
In the ‘NdNp’ notation, what is the designation of the polymerase that codes for all viruses that have RNA genomes?
RdRp
In the ‘NdNp’ notation, what is the designation of the polymerase that replicates DNA by assembling nucleotides?
DdDp
What are polymerases made up of?
They are either structural proteins, or (often) non-structural proteins (depending on the specific type of virus)
-one exception is RdDp is always found in the virus particle
What are modifier subunits composed of for viruses that employ them?
non-structural proteins- (never found in virus particle and always made from scratch within infected cells)
What are two distinct post-transcriptional modifications that may occur during the maturation of mRNA molecules in eukaryotic cells?
intron and exon splicing
a 7-methylguanosine triphosphate cap attached to the 5’ end that aids in an attachment site in protein synthesis.
3’ is polyadenylated with the poly (A) tail
In the ‘NdNp’ notation, what is the polymerase that reverses transcriptase and generates an CDNA from an RNA template used by retroviruses?
RdDp
In what class of single-stranded RNA viruses is the RdRp always a structural protein?
negative since single stranded RNA viruses
What types of virus encode ribosomal RNA molecules?
NONE- no viral genome encodes rRNA
antiparallel
two strands that go in opposite direction
3’ -> 5’
5’ -> 3’
Base
heterocyclic compound
Nucleoside
base + sugar
nucleotide
base + sugar + phosphate
What two functions are invariably associated with the proteins encoded by any given virus?
genome protection and genome replication
