Virus Replication Strategies Flashcards
What size can virus genomes be between?
2kb and 2.5Mb
What is a good example of an enveloped virus?
Influenza
What does being enveloped or non-enveloped define?
The replication cycle
What is a good example of a non-enveloped virus?
Polio
What are non-enveloped viruses coated by?
A capsid only , they possess no membrane
How do enveloped viruses get into cells?
Have to fuse the membrane with the membrane of a cell
How do non-enveloped viruses get into cells?
Have to go into invaginate vesicle and fuses the vesicle
What are repeating subunits of a capsid called?
Capsomeres
What shapes can capsids take?
Helical
Icosahedral
Complex
What is the most common shape of viruses and the least common?
Icosahedral is most common
Helical is rare for medically important viruses
Complex viruses - no human pathogens like this
What can virus families be assigned based on?
Nucleic acid - DNA or RNA
Ss or ds genome
Positive sense or negative sense
Virion architecture
What is class 1 Baltimore system?
DsDNA virus
What is class II Baltimore classification?
SsDNA
What is class 3 Baltimore classification?
DsRNA
What is class 4 Baltimore scheme?
Positive ssRNA
What is class 5 Baltimore scheme?
Negative ssRNA
What is class VI Baltimore scheme?
Ss (+) RNA with DNA intermediate
What is class VII Baltimore scheme?
DsDNA with RNA intermediate
What is the maturation process?
Assemble a particle but it is not infectious so the maturation makes it infectious
What are the stages of virus life cycle?
- Binding
- Entry (and Uncoating)
- Protein expression
- Genome replication
- Virion assembly
- Maturation
- Release of particles
What is examples of tissue tropism?
Measles (skin cells) vs mumps (salivary glands)
What are examples of species tropism?
Togavirus (both insect/mammalian cells)
Poliovirus (primate cells)
Where do RNA viruses often replicate?
In cytoplasm
Where do DNA viruses often replicate?
In the nucleus
What are the 3 types of structural proteins?
Capsid proteins
Envelope proteins
Matrix proteins
What do alpha proteins mainly trigger?
Mostly transcription factors and then expression of beta genes to make beta proteins
What do beat proteins do?
Accumulate and binds to promoters and transcription factors that allow expression of gamma genes and therefore gamma proteins
