viral diversity Flashcards
what is the first virus discovered
tobacco mosaic disease
-took extract from disease plant to see if it infects healthy plant
first viruses that are filterable agents in cattle and human
cattle: foot and mouth disease
humans: yellow fever
difference between positive sense RNA and negative sense RNA (single stranded RNA virus)
-are there genomes infecious
-are there genomes function mRNAs
-translation with RdRp (RNA replicase)
-error rate
positive= genome is infecious.
-genomes are function mRNAs
-RdRp catalyses the replication of RNA fro. RNA template
-highly error prone from going positive to negative back to positive genome
negative= genome not infecious
-genomes not functional mRNAs
-the host ribsome cannot translate the genome to creare RdRb. therefore the viroin already contains RdRb already.
what is viroin diversity
extracellular infecious form of virus. consisting of RNA and DNA and envelope
what is demarcation of viruses
and examples
how similar do viruses need to be to classify them as same species
e.g. hepatitus C
-poliovirus
phages
what kind of phages use lytic and lysogenic cycle of viral reproduction
and examples
lytic= virulent phages (phage T4)
lysogenic and lytic =temperate phages (lambda)
describe lytic cycle in viral reproduction
destruction of infected host cell and it’s membrane.
replicstion happens seperately
describe lysogenic cycle of viral reprodution
-what events can release prophage and result in cell divison
phage infects bacterium and inserts DNA into bacterial chromosome. allowing phage DNA (prophage) to be copied and passed along with cells own DNA
-stress, UV radaiation
example of RNA virus in animals
foot and mouth disease
difference between antigenic drift and shift
drift= small changes (via mutations) in influenza virus gene. HA and NA protein driver by high error rate of RdRp.
shift= major change in influenza virus. new HA and NA proteins. can happen if flu virus in animals is now able to infect humans. e.g. reassortment of segments
