lytic cycle

In the lytic cycle, which is considered the main cycle in viral replication, once the viral DNA enters the cell it transcribes itself into the host cell’s messenger RNAs and uses them to direct the ribosomes.

The host cell’s DNA is destroyed and the virus takes over the cell’s metabolic activities.

The virus begins using the cell energy for its own propagation. The virus produces progeny phages. These replicate fast, and soon the cell is filled with 100-200 new viruses and liquid. As the cell starts getting overcrowded, the original virus releases enzymes to break the cell wall. The cell wall bursts – this process is called lysing - and the new viruses are released.

So, in short, in the lytic cycle, the virus hijacks the infected cell and then destroys it. The lytic cycle occurs in virulent viruses. The symptoms from a viral infection occur when the virus is in a lytic state.

When a lambda phage infects a bacteria, it can either enter into the lytic cycle or the lysogenic cycle. In the lytic cycle, the host cell’s machinery is hijacked to only reproduce the phage DNA until enough baby phages can assemble and burst out of the cell to wreak havoc on nearby cells. In the lysogenic cycle, the phage DNA is incorporated into the host cell DNA and is copied quietly alongside it as the cell reproduces. Eventually, through some environmental trigger, this dormant phage DNA in the lysogenic cycle enters the lytic cycle and proceeds as described above.