Viruses do not replicate by themselves. They require a host cell that they must use to undergo replication. The end result is the death of the host cell. The five basic stages of viral replication are listed and discussed below.
Attachment: The virus attaches itself to the membrane of the host cell. This interaction is quite specific and involves proteins on the viral surface interacting with receptor proteins on the cell's membrane.
Penetration: The virus then injects its genetic material encased in a protective capsid into the host cell. Plant and bacterial cells have a rigid cell wall that must first be broken through in order to access the membrane.
Uncoating: The capsid is shed by breaking down the proteins with enzymes. The viral genome then has access to the host cell.
Replication: The viral genome is replicated within the cell and then viral protein synthesis occurs within the cell using special viral mRNA. The viral proteins assemble into a new virus.
Lysis: The new viruses then rupture the cell membrane of the host cell to release themselves. The host cell is killed in the process.