Viruses and Prions Flashcards
What are the general properties of viruses?
- Small size
- Genome: RNA or DNA
- Metabolically inert:
- Do not possess ribosomes/protein synthesis
- Some have enzymes
What is the name given to a complete virus particle?
Virion
What is the name for the lipid membrane around SOME viruses?
Envelope
What is the name given to the protein shell found in viruses?
Capsid
What are the protein units that make up the capsid called?
Capsomers
What does the nucleic acid genome in a virus consist of?
DNA or RNA
What are the 5 ways virus transmission can occur?
- Inhalation via respiratory tract
- Ingestion via GIT
- Inoculation: Skin abrasions, mucous membranes, injections, bites
- Congenital: mother to fetus
- Sexual transmission
What organs/systems are specifically affected by viruses?
- Nervous system
- Respiratory tract
- Localised disease of skin and mucous membranes
- Eye
- Liver
- Salivary glands
- GIT
- STD’s
What is the ‘cytopathic effect’ viruses can have on cells?
Structural changes in the host cells which can case cell lysis (cell death)
What is the transformation of a cell by a virus?
The cell is not killed, but it is changed to a cancerous cell
What is the ‘latent infection’ a virus can have on a cell?
The virus remains in the cell with no obvious effect on the cells function
What are the key stages in replication?
- Attachment
- Penetration
- Uncoating
- Synthesis of viral components
- Assembly
- Release
What are the 2 ways viruses can release?
- Rupture
- Gradual extrusion
What is a direct method of viral infection diagnosis?
Molecular - using Polymerous chain reaction
What is an indirect method of viral infection diagnosis using serology?
ELISA and Western blotting
