Viruses do not reproduce. The living cell in which the virus reproduces is called a host cell. They use these host cells to replicate themselves by creating an exact copy of the virus. Two main types of reproductive cycle are observed in the virus namely Lytic Cycle and Lysogenic Cycle.
Reproduction of virus through Lytic cycle: This cycle
is completed with several steps which are as follows:
1. Attachment: In this first step, the Virus is
attached to the host cell.
2. Entry: Then genetic material is injected into the
host cell.
3. Replication: The virus takes over the cell's
metabolism, causing the creation of new proteins and nucleic acids by the host
cell's organelles.
4. Assembly: Then proteins and nucleic acids are
assembled into new viruses.
5. Release: Finally virus enzymes cause the cell to
burst and viruses are released from the host cell. These new viruses further
infect other cells and this process continues.
Fig: Reproduction of virus through Lytic cycle
Reproduction of virus through Lysogenic cycle: This
cycle is completed with several steps which are as follows:
1. Attachment: In the first step, the virus is
attached to the host cell.
2. Entry: Then genetic material is injected into the
host cell.
3. Integration: Viral DNA integrates into the host
cell's genome.
4. Replication (lysogenic cycle): When the host cell
replicates, viral DNA is copied along with host cell DNA. Each new daughter
cell is infected with the virus.
5. Induction: When the infected cells are exposed to
certain environmental conditions, viral DNA is activated and enters the lytic
cycle.
6. Replication (lytic cycle): The virus takes over
the cell's metabolism, causing the creation of new proteins and nucleic acids
by the host cell's organelles.
7. Assembly: Proteins and nucleic acids are assembled
into new viruses.
8. Release: Then finally virus enzymes cause the cell
to burst and viruses are released from the host cell. These new viruses can
infect other cells.
Fig: Reproduction of virus through Lysogenic cycle