Lecture 1 content Flashcards
what defines a virus
its subcellular
needs host for replication
they can be both lytic causing cell death or dormant/latent
what is the most effective type of virus
one which does not kill the host as if the host is dead the virus cannot spread effectively
where does the majority of viral replication take place in the cell
the cyto
what does the cow example comparing a toxin to a virus show
this example shows that unlike a toxin virus cannot be serially diluted over generations as they are constantly making copies of them self’s
what are the 7 majors compents of a virus and there function
VIRION = virus particle, a single infectious agent
ENVELOPE = derived from host cell lipid bilayer, covers virus capsid
CAPSID = protein structure surrounding viral genome
GENOME = nucleic acid of the virus, RNA or DNA
NUCLEOPROTEINS = proteins that directly associate with the virus genome
NUCLEOCAPSID = nucleic acids, structural, and replicative proteins
MATRIX PROTEIN = protein on inner surface of lipid bilayer of viral envelope
what are the 5 standard morphological groups in which viruses can be categorized
1) non-enveloped/helical capsid
2) Non-enveloped / icosahedreal capsid
3) envleoped/ helical
4) enveloped/iosahedral capsid
5) complex
the tegument is a unique structure found in only a few viruses what is it?
Thick group of proteins underneath herpesvirus envelope(only in herpesvirus)
how is the virus membrane derrived?
From the host membrane, the materials needed for this can be taken from a variety of places in the host cell
what is the capsid of a virus made of and how does it assemble
a virus capsid is made out of proteins this proteins(repeating) and are able to self assemble, this sturctures are either helical, isohedral or complex
what kind of genomes are viruses able to have
Both RNA and DNA but cannot have both at the same time must be one or the other
how do viruses make there small genome as efficient as possible
they have overlapping genes which enable the genome to encode for more mRNA then the size of the genome itself
also fact– 90% of the viral genome is used for coding whereas only 5% of the human genome is used
what are some methods which viruses employ to create a more efficient genome
mRNA splicing
readthrough of stop codons
Multiple start sites
overlapping genes
frameshifting(controlled)
Lytic infection
and enzymes which cause the cell to degrade and “blowup”
what is a chronic infections
infections that produce small amms of virus over a long period of time this avoids the immune system this can be seen in hep C
