POS - Virology Structure Flashcards
What are viruses dependent on?
The metabolic and genetic functions of the host
Materials and habitat from the host.
How is a virus not cellular?
Lack of organelles (no internal membranes or cytoplasm)
What does the host provide to the virus structure?
Building blocks/amino acids and nucleotides
Protein synthesis machines/ribosomes
Energy/ATP mitochondria
Do viruses divide?
NO!
They disassemble and cease to exist. A progency is an assembly of viral proteins and nuclei acid.
What enzymes do the viruses have to code?
RNA dependent RNA polymerase
Reverse transciptase ( copy RNA to make DNA)
How can viruses be visualised?
Electron microscope
Whats the largest mammalian viruses?
Poxviridae
Filoviridae
What are the smaller viruses?
Picornaviridae
Parvoviridae
What are the shapes of viruses?
Spherical and smooth
Irregular and roughly spherical
Projections on surface
Adenoviruses with fibres on corners
Irregular shape e.g. bullet
What does a viron consist of?
Nucleic acid, surrounded by a capsid and maybe an envelop
Whats a DNA virus?
ds or ss (most are ds)
Can be circular
All monopartite (on single piece of DNA)
Replicate in the nucleus with larger genomes
What is a RNA virus?
ds or ss (-ve or +ve)
Some monopartite and some segmented, with single gene on segment or 2 segments one for structural and one for not.
Replicate in a cytoplasm
What is the difference between -ve or +ve ssRNA?
+ve acts as mRNA so can be replicated directly to proteins
-ve needs to synthesise +ve mRNA before can be translated so less infectious
What is a icosahedral capsid?
12 corners, 20 faces, composed of capsomers
Mostly not enveloped.
What is an example of an icosahedral capsid?
Non-enveloped icosahedral, built of 252 capsomers
