Virology Flashcards
what viruses have a lytic life cycle
(cause the cell to explode)
T3, T7 and T2, T4
(double stranded)
what viruses are temperate (integrate their genomes into a host chromosome)
Mu and lambda
(double stranded)
what is a lysogenic cell?
a bacterial cell which can produce and transfer the ability to produce a phage
what is a prophage?
A prophage is a bacteriophage genome that is integrated into the circular bacterial chromosome
what is transduction?
the process by which a virus transfers genetic material from one bacterium to another
what happens during the eclipse period of viral reproduction?
causing infection and the appearance of new mature virus in a host cell
what are plaques on agar
zones of lysis
where does the T1 virus attach
iron transport protein
what type of viral life cycle occurs when viruses lyse host cells after infection
virulent mode
what type of viral life cycle occurs when viruses replicate their genomes in tandem with the host genome and without killing the host
temperate mode
(viruses can also be lytic)
The time elapsed between successful cell infection and the start of virus production in the cell is called what?
the eclipse period
The period that is the time taken by a phage particle to reproduce inside an infected host cell is called what?
the latent period
what bacteriophage is used as a cloning and dna sequencing vector in genetic engineering
bacteriophage M13
- does not lyse the cell
where does lamda virus attach itself on a cell (can be used in genetic engineering)
specific site on the chromosome
where does mu attach itself on the cell (can be used in genetic engineering)
generalized attachment to the cell (anywhere)
mu: mutation
can temperate viruses kill the host cell?
yes through lytic cycle
what is the lysogeny state of a virus?
state where most of the virus gene is not expressed and virus genome (prophage) is replicated in synchrony with host cchromosome
what is a lysogen
a bacterium containing a prophage
what are cos sites
sticky ends on lambda virus
what are the twoo repressor prooteins that control the regulation of lytic vs lysogenic events in lambda
- cl protein: causes repression of lambda lytic events
- cro repressor: controls activation of lytic events
how does the virus use the cell to protect it’s dna?
by using 5-hydroxymethyl-cytosine which endonucleases cant recognize
what is a nucleocapsid
the capsid of a virus with the enclosed nucleic acid.
picture of a nonenveloped polyhedral virus
picure oof morphology of an envelope heliccal virus
picture of helical virus
what is a syncytia
evolutionarily conserved cellular structures form by the multiple cell fusions of uninuclear cells
what is a cytopathic effect?
The changes in cell morphology caused by infecting virus are called cytopathic effects
what DNA virus forms an inclusion in the cytoplasm?
prox virus
DNA viruses infect what part of the cell
nucleus
RNA viruses infect what part of the cell
cytoplasm
how do viruses cause cancer?
when the virus effects the chromosome of a cell
what are cancerous viruses called?
oncogene viruses
-hepetitis B and HPV
how do you determine the number of plaque particles
of physical particles/# of infectious particles
what rule must all viruses follow to become infectious
viral genomes must make mRNA that can be read by host ribosomes
what are the 7 classes of key virus families
parovirus
retrovirus
poliovirus
influenza virus
reovirus
herpes virus
hepatitis B
what is the purpose of the 5’ cap
helps the ribosome attach to the mRNA and start reading it to make a protein
when a virus only has a nucleic acid and protein coat it is called what?
a naked virus because it has no envelope
what are the five single stranded positive RNA viruses
- Picornaviridae (Poliovirus, Rhinovirus)
- Caliciviridae (gastroenteritis)
- Coronaviridae (SARS)
- Flaviviridae (Yellow fever virus, West Nile virus, Hepatitis C virus, Zika virus)
- Togaviridae (Rubella virus, Equine encephalitis virus)
five single stranded single stranded RNA
- Paramyxoviridae (Measles virus, Mumps virus)
- Rhabdoviridae (Rabies virus)
- Filoviridae (Ebolavirus, Marburg virus)
- Orthomyxoviridae (Influenza virus)
- Arenaviridae (Lassa virus)
what are viroids
an infectious entity affecting plants, smaller than a virus and consisting only of nucleic acid without a protein coat
precursor for prions disease
PrPc to PrPsc
