All viruses have to penetrate, replicate and exit a cell. The details of how they do this varies.
|
| |
The life cyle is generally divided into four stages. |
| 1. |
Attachment
Attachment is a specific binding between viral surface proteins and their receptors on the host cellular surface. This specificity determines the host range of a virus.
|
| 2. |
Penetration
Once the virus attaches to the cell the virus may enter the host cell through receptor mediated endocytosis or other mechanisms.
|
| 3. |
Uncoating
Uncoating is a process that viral capsid is degraded by viral enzymes or host enzymes.
|
| 4. |
Replication
Replication involves assembly of viral proteins and genetic materials produced in the host cell.
|
| 5. |
Release
Viruses may escape from the host cell by causing cell rupture (lysis). Enveloped viruses (e.g., HIV) typically "bud" from the host cell. During the budding process, a virus acquires the phospholipid envelope containing the embedded viral glycoproteins. |
