Virology Flashcards
What is a virus? (3)
- A set of gene (instruction in DNA & RNA) packaged in a virion (protein coat).
- Obligate intracellular parasite - meaning it cannot finish its lifecycle w/o a host.
- Incapable of self-replication
Capsid
Protein shell around nucleic acid core, made of repeating structure units
Nucleocapsid
- Capsid + nucleic acid
- Protective shell around genetic material.
Envelope viruses
- Some virus types have lipid wrap around nucleocapsid.
- Warm magical blankie to keep them safe.
Virion
Hint: Villian’s sidekick
- Complete infective virus particle.
- What viruses use to infect host cells.
Viral structure:
Enveloped (5)
Hint: De-immortalized god
- Coat of lipids & proteins.
- From host during budding off.
- Easier to kill.
- Less resistant to disinfectants.
- Examples:
- Adenovirus
- Kennel cough (CaDV-2)
Viral structure:
Non-enveloped (6)
Hint: Nothing to hide behind
- Capsid coat.
- More virulent.
- More resistant to harsh environment.
- Can’t survive long in host.
- Retain infectivity after drying.
- Examples:
- Influenza
- COVID-19
T/F: Non-enveloped viral structures can mutate rapidly
True!
How do viruses multiply? (3)
- Enter: Virus enters the cell.
- Entertainment: Virus mult. in the cell.
- Exit: Virus exits the cell.
Step 1 of virus multiplying - Enter:
Virus enters a cell by two methods
- Direct cell membrane fusion - by injecting into the cell. Think of how a mosq bite works.
- Endocytosis (inward budding)
Step 2 of a virus multiplying - Entertainment:
How does it multiply?
Host cell does all the work on multiplying after the virus has entered the cell.
Use and abuse the host cell!
Step 3 of virus multiplying - Exit:
How does the virus leave/exit the cell? (2)
- Virus can kill the cell & release with the cell rupture. (This one isn’t great for the host)
- Budding from cell membrane. They literally put their coat on, then leave the cell.
What are the three responses the body can have to a virus?
- Immune system eradicates virus:
- Interferon
- Antibodies & Lymphocytes - Cell death or host death (Uh oh)
- Chronic infection:
- Viral genome becomes apart of the host cell DNA
What is interferon?
Hint: “Emergency alert system”
CHEMICAL the body makes to protect itself from viral infection
How do viruses cause death of cells?
1. D
2. E
3. A
4. T
5. H
- Damage cell membrane.
- Extinguish host cells normal mechanisms for survival (DNA, RNA, protein synthesis).
- Attract lymphocytes to kill invaded cell.
- Transform cell into cancer.
- Host killed due to dependence on invaded cells.
Your friend makes a new friend. She’s okay. All the other friends start to like her but you know there’s something off. New girl notices it and turns everyone against you. It’s too late now. You’re dead to them.
