Many techniques can be employed in order to understand how viruses enter, replicate and assemble in cells. In 1939, Ellis and Delbrück developed a method to study a single round of virus multiplication using a one step
growth curve. This method is possible due to the synchronization of replication of phage in the sample (Flint, 2002).
A one step
growth curve experiment begins when bacteriophage are infected with a very large number of
phage particles. The large number of
phage particles ensures all bacterium are rapidly infected. This high level of infection is called multiplicity of infection (MOI) and can be achieved with a phage to host ratio of 5 to 10 plaque-forming units (PFU) per cell (Flint, 2000). The phage/cell mixture is then diluted synchronizing the infection. As the infection of bacteriophage is synchronized, the interaction of virus with the cell population can be seen as a single interaction between phage and cell. In order to visualize the infection over time, samples of the phage/cell mixture are removed at intervals, plated and then quantified using the plaque assay (Madigan, 2000)
It is possible to divide the multiplication cycle of viruses into five periods. The first period is the eclipse period
