The T4 bacteriophage 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, the T4 bacteriophage hijacks the bacterial machinery to replicate itself, ultimately leading to the destruction of the host cell. T4 bacteriophages are part of the Caudovirales order and are known for their role in molecular biology and genetics research. They are also being studied for potential applications in phage therapy, which aims to use viruses to target and kill harmful bacteria, offering an alternative to traditional antibiotics.