Question

How does T4 virus release or exit from the bacterial host cells and which step of viral replication is not required for this virus

Answer 1

After the T4 has replicated all of their parts, they follows an assembly  process. The proteins that make up the capsomeres assemble themselves into the heads and "reel in" a copy of the phage DNA.

The tail and accessory structures assemble and by using a bit of lysozyme in the tail plate. The viruses arrange their escape from the host cell during the assembly process.

While the viruses are assembling, lysozyme is being produced as a late viral protein. Part of this lysozome is used to escape from the host cell by lysing the cell wall peptiodglycan from the inside. This accomplishes the lysis of the host cell  and the release of the mature viruses which spread to nearby cells, infect them, and complete the cycle. The life cycle of a T-phage takes about 25-35 minutes to complete. Because the host cells are ultimately killed by lysis, this type of viral infection is referred to as lytic infection.

T4 phage has some unique features, including:Eukaryote-like introns. High speed DNA copying mechanism, with only 1 error in 300 copies special. DNA repair mechanisms.