Experiments conducted in 1952 by Alfred Hershey and Martha Chase demonstrated how the DNA of viruses is injected into the bacterial cells, while most of the viral proteins remain outside.

The first phages that were studied in detail included seven that commonly infect E. coli.

The phage can attach to the surface of a bacterium using the proteins on its 'feet' (tail fibers), and inject its genetic material (either DNA or RNA).

This genetic material uses the host cell's ribosomes to replicate, and synthesize proteins for the capsid and tail of the phage.

New phages are assembled within the cell until the cellular membrane lyses (splits open).