L8 virus and virology Flashcards
How many groups in the Baltimore classification system
7
List the four traits of viruses
- Virion
- Capsomere
- Assembly
- Capacity to evolve
Decribe the four traits of virsuses
- Virion - extracellular infectious stage
- Capsomere - all have this cover that protexts nucleic acid in the virion
- Assembly - infected cells synthesise the virons component parts and then assembly into new virions. (in cytoplasm)
- Evolve - bc of its min composition of nucleic acids and protein capsomeres, virsus can change through evolution and alter nucleic acid in heritable ways.
What are viruses
Obligate intracellular parasites
What requires host cells to multiple with no machinery for protein synthesis and energy production?
Viruses
Virus replication simple
Assembly of pre-made components
Viruses are infectious particles minimally made up of what two things
Nucleic acids and proteins
What is a capsid
The protein coat of capsomeres that surrounds the nucleic acids.
What two classes are virions separated on?
Enveloped (has proteinaceous lipid bilayer) and naked (doesn not have lipid bilayer)
Name Capsid shapes
- Spherical
- Helical
- Icosahedrons
- bacteriophages
Spherical capsids are actually icosahedrons, which approximate the volume of a sphere yet are constructed from repeated subunits. Spherical capsids are somewhat rigid, whereas helical capsids can be rigid or flexible, depending on the virus.
Spherical capsids are somewhat ____, whereas helical capsids can be ____ or ____, depending on the virus.
rigid
rigid or flexible
Some bacteriophages combine icosahedral and helical elements, so that their heads that are full of nucleic acids are icosahedral but their tails are what?
helical assemblages of specialized tail proteins.
what is a Nucleocapsid
In some viruses, the nucleic acid genome and the capsomeres are so intimately associated that their structure is termed a nucleocapsid.
Capsid together with enclosed nucleic acid
Viral Structure
- Complete virus particle
- Infectious
- Composed of nucleic acid surrounded by protein coat, for protection
- Some viruses are enveloped