The viruses that live as parasites on bacteria are called bacteriophages or simply phages. Bacteriophages are viruses that infect and replicate within bacteria. They are highly specific to their host bacteria, often infecting only certain strains or species of bacteria.
Bacteriophages have a complex structure consisting of a protein coat (capsid) that surrounds the genetic material, which can be either DNA or RNA. Some bacteriophages have additional structures, such as a tail or spikes, that help them attach to and infect specific bacteria.
The life cycle of bacteriophages typically involves several stages, including attachment to the bacterial cell, injection of the genetic material into the host cell, replication and expression of the viral genes, assembly of new virus particles, and release of the newly formed viruses from the host cell.
Bacteriophages are important in many aspects of biology and biotechnology, including the study of genetics and molecular biology, as well as the development of phage therapy as a potential alternative to antibiotics for the treatment of bacterial infections.