Bacteriophage Lambda is a type of virus that specifically infects Escherichia coli (E. coli) bacteria. It is a well-studied example of a bacteriophage, which are viruses that target bacteria. Lambda can exist in two states: the lytic cycle, where it replicates and destroys the host cell, and the lysogenic cycle, where it integrates its DNA into the host's genome and can remain dormant for extended periods. Researchers use Bacteriophage Lambda in molecular biology and genetics to understand gene regulation and DNA replication. Its simple structure and ability to transfer genetic material make it a valuable tool in genetic engineering and biotechnology.