5. Overview of Viruses Flashcards
What neutralizes the viral particles?
Antibody to the viral spikes
what is the importance of a mutating viral spike?
mutated spike = new spikes = human antibody can’t recognize. Also, expands the range of potential hosts a virus might infect.
Virus consist of:
- Genes (genome that is ds DNA/RNA, ss DNA/RNA
2. Capsid (protein bottle/shell)
2 ways virus leave the host cell:
- Budding
2. Lysis
what is budding?
Virus leaves the host cell in a membrane bubble that stays around the capsid and forms an envelope. Envelope usually has spikes.
What is lysis?
Virus triggers host cell to break open, allowing naked nucleocapsids. Spikes are integrated into capsid.
What are the 5 outcomes/response of host cells to viral infections?
- Abortive
- Lytic
- Chronic, non-lytic
- latent
- Transformation
Abortive is….
When no progeny virus are produced in host cell.
Lytic is….
The acute process where viral progeny are releasted by death (Lysis) of the host cell.
Chronic, non-lytic, is…
when virally infected cells slowly release viral progeny without dying.
Latent is…
when virus genome usually becomes integerated into the cell DNA and stays dormant. Virus can ‘re-awake’ at anytime and produce progeny.
Transformation is…
when virus causes cell to proliferate uncontrollably.
Virus capsids can be:
helical or icosahedral
+ Viral DNA/RNA is “____________” whereas - DNA/RNA is “_______.”
+ Viral DNA/RNA is in “the same orientation as mRNA” whereas - DNA/RNA is “anti-sense.”
Viruses are simply “_____ ________”
Viruses are simply “genetic instruction”
The 2 key steps for virus to replicate and cause disease are:
- Replication of their genetic material
2. Produce positive-stranded mRNA (+RNA), to replicate their protein components.
What is the overall cycle for a virus to infect a host cell? (6 steps)
- Attachment - to host cell
- Penetration
- Uncoat protein capsid - to expose viral genome
- Replicate viral genome and structure
- Assemble new virus
- Release
Viremia is….
The release of viral agent into the blood.
Viroid is…
a nucleic acid polymer lacking a capsid (basically a virus without a capsid. Only infects plants)
Prions are…
infectious agents that are only protein. Infects humans and animals
Virus have “______” effect. Many infections occur with little or non obvious symptoms.
Virus have “iceberg” effect. Many infections occur with little or non obvious symptoms.
