Pages

Monday, August 2, 2010

Virus Replication


There are 6 distinguish stages of viral replication;

1. Attachment
-affinity between the virus and the host cell's plasma membrane permits this stage.

2. Penetration
-virus particles are brought inside the cell, either by endocytosis or directly pass through the cell's plasma membrane.

3. Uncoating
-removal of capsid, to expose the viral nucleic acid.

4. Biosynthesis
-synthesis of viral nucleic acid, capsid, and enzymes.

5. Maturation
-two phases, phase I is assembly which the polypeptide chains assembled into capsomeres to form procapsid
-phase II is the intake of nucleic acid into the procapsid, forming a complete virion.

6. Release
-occurs by 3 mechanisms.
-cell lysis (host cell is killed by virus-induced)
-budding (no cell killing, usually by enveloped viruses)
-cell degeneration (after cell death, the virus released. non-virus-induced)