Introduction to Viruses Flashcards
What size are viruses?
Small, from 20-400 nm in diameter
Viruses are non-cellular.
What does this mean?
Genetic element that cannot replicate independently of a living (host) cell
Name the three structures a virus could have.
Icosahedral, Helical or Complex.
Describe the Icosahedral structure of a virus.
20 faces, each an equilateral triangle
Describe the helical structure of a virus?
Protein binds around DNA/RNA in a helical fashion
Describe the complex structure of a virus.
Simple- just neither helical or icosahedral.
Where do viruses replicate?
Only replicate inside a host cell.
What types of cells do viruses infect?
Most viruses have a specific host range and only infect specific host cell types.
What is the study of viruses?
Virology
Define virion.
Extracellular form of a virus.
Where does a virion exist?
Exists outside host and facilitates transmission from one host cell to another
What do virions contain?
Contains nucleic acid genome surrounded by a protein coat and, in some cases, other layers of material
List the ways a virus family can be classified.
According to-
-Virion shape / symmetry
-Presence / absence of envelope
-Genome structure
-Mode of replication
Name the four ways a virus can be classified regarding taxonomy.
Order, family, genus and species.
Describe the structure of a virion.
Basically-
Nucleic acid is enclosed in a protein capsid which is then enclosed in a lipid envelope.
There are spike projections covering the virion.
How do viruses replicate?
- Viruses attaches to cell wall.
- Virus becomes uncoated so leaves it’s outside.
- Protein capsid and nucleic acid enter the host cell to allow replication of the nucleic acid.
4.Protein synthesis occurs. - Genomic nucleic acid synthase and newly synthesised virus proteins get assembled to produce the new virion.
- New virion is released to go and infect another cell.
->this wasn’t explained v well tbh did the best i could
List a few of the many ways transmission can take place.
Give examples
Blood borne (HIV, Hep b)
Sexually transmitted (HIV, Hep b)
Vertically transmitted (HIV, Hep b)
Droplet (influenza)
Air borne. (measles, chickenpox).