Viruses can survive outside a host but they require host cells to reproduce. There are two lifecycle pathways that viruses can take:
1. As soon as the virus penetrates the host cell, it synthesises proteins that break down the host’s DNA, so that it can take over the cell’s machinery.
2. It uses the cell’s machinery to synthesise proteins for the production of new virus particles.
3. This causes the viruses to burst out of the host cell in a process called lysis, thereby killing the cell.
4. The process is then repeated with nearby cells.
1. The virus attaches to the surface of the host cell and then penetrates it.
2. It injects its DNA into the host cell’s cytoplasm.
3. The host cell replicates, and the viral DNA is also copied in the process.
4. Under certain conditions, viral DNA will undergo induction. At this point, the lysogenic cycle transitions to the lytic cycle.