Viruses Basic Life Cycle

The life cycle of viruses differs greatly between species but there are six basic stages in the life cycle of viruses:

Attachment

Penetration

Uncoating

Replication

Assembly

Release

Attachment: is a specific binding between viral capsid proteins and specific receptors on the host cellular surface. This specificity determines the host range of a virus.

Penetration: following attachment, viruses enter the host cell through receptor mediated endocytosis.
Uncoating: is a process in which the viral capsid is removed is degraded by viral enzymes or host enzymes thus releasing the viral genomic nucleic acid.
Replication: involves synthesis of viral messenger RNA for viruses, viral protein synthesis and assembly of viral proteins and viral genome replication.

Assembly: the virus particles are put together.

Viruses are released from the host cell by lysis. Enveloped viruses usually are released from the host cell by budding.