The phage genome replication starts as soon as the bacterial replication stops. The replication of the phage DNA begins within a minute. It requires only five minutes depolymerizing the phage DNA. The nucleotides help in replication of the phage genome. New phage capsids start developing after twelve minutes. Various phage particles get assembled within the bacterial cell. The genome or the phage DNA gets inserted into the capsid heads. Cell lysis enables release of the phages. It takes twenty minutes to release the progeny. Each lytic cycle produces 200 to 300 bacteriophages. The progeny phages are further capable of infecting the other bacteria. This experiment was carried out by Ellis and Delbruck in 1939. One step growth curve represents the results. The latent period lasts from 0 to 22 minutes revealed that there was no change in the number of cells during the first twenty-two minutes of the infection. The phages are mixed with the bacteria and plated on a culture medium. An entire lawn of bacteria is allowed to grow on the medium. Each phage infects the bacterium on the plate and the phages released from one infection attack the adjacent bacteria. The cycle continues in this way. The result of lysis depicts a clear patch in the lawn of bacteria. The clear patch is known as a plaque. Most of the phages undergo a lytic cycle. Some phages undergo a lysogenic cycle.