Bacteriophage T4 is a type of virus that specifically infects bacteria, particularly Escherichia coli (E. coli). It has a complex structure, featuring a head that contains its genetic material and a tail that helps it attach to and penetrate bacterial cells. Once inside, T4 hijacks the bacterial machinery to replicate itself, ultimately leading to the destruction of the host cell. This bacteriophage is widely studied in microbiology and genetics due to its well-characterized life cycle and ability to serve as a model for understanding viral behavior. Researchers also explore its potential applications in phage therapy, a method of using viruses to target and kill harmful bacteria.