How is a bacteriophage primarily released from a host cell?

Bacteriophages, or phages, are viruses that specifically infect bacteria. The primary method by which a bacteriophage is released from a host cell involves the process known as lysis. When a bacteriophage infects a bacterial cell, it takes over the host's machinery to replicate its own genetic material and produce new virions (virus particles). As the phage replicates, it accumulates within the host cell, leading to cell swelling and ultimately causing the bacterial cell to burst, or lyse.

This lytic phase is characterized by the release of numerous new phage particles into the surrounding environment, which can then go on to infect other bacterial cells. The lysis of the host cell is a critical step in the viral life cycle, allowing the phage to propagate and spread.

Other methods mentioned, such as exocytosis, budding, and cell fusion, are more characteristic of eukaryotic viruses, where the virus may exit a host cell by packaging itself into vesicles that fuse with the cell membrane or by integrating into the host’s cellular processes in a more nuanced way. However, bacteriophages primarily utilize lysis as their primary means of exit from the bacterial host.