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Properties of Viruses
- Nucleic acid can be double DNA, single DNA, Single RNA, or double RNA
- Structure consist of protein shell (capsid) surrounding nucleic acid core
- Lack enzymes and most metabolic processes
Fully formed virus able to establish an infection
What is the general structure of a virus
- Virus particle.
- a) Covering; capsid or envelope(not found in all viruses)
- b)Central Core; Nucleic acid (DNA or RNA) or matrix proteins enzymes (not found in all viruses)
All viruses have
Capsids - Protein coats that enclose and protect their nucleic acid
- Construct capsid
- Identical subunits that are made of proteins
The capsid paired with nucleic acid
- Not found in all viruses
- External covering
- Mostly in animal viruses
Viruses not containing envelopes are called?
When are envelopes acquired?
When the virus leaves the host cell
- Exposed proteins on the outside of the envelope.
- Essential for attachment of the virus to the host cell
- AKA atypical viruses
- Some bacteriophages(viruses) have a polyhedral nucelocapsid along with a helical talk and attachment fibers
They lack a typical capsid and have an unusual shape
- Either DNA or RNA but never both
- Carries genes necessary to invade host cells and redirect cells activity to make new viruses
- Synthesis of DNA from RNA
- AIDS virus
Some viruses use what to help replicate?
- Pre-formed enzymes
- Polymerases and replicases
6 phases of animal virus multiplication
- Adsorption- Binding of virus to molecule on host cell
- Penetration- Genome enters host cell
- Uncoating- Viral nucleic acid is realeased from capisd
- Synthesis- Viral compnents are produced
- Assembly- New viral particals constructed
- Release- assembled viruses are released by budding(Exocytosis) or lysis.
- Virus induced damage to cells
- Changes in shape/size
- Cell lysis
- Alter DNA
- Transform to cancerous cells
- Nuclear inclusions
Viral infection of human liver cells
Viral infection of intestinal and nerve cells
Viral infection to various cells of many mammals