During the lytic cycle, what is the first step after encountering a host cell?

• A. Host cell lysis
• B. Attaches to host cell and inserts genetic material
• C. Integration into host chromosome
• D. Assembly of new viruses

Answer: (B)

In the lytic cycle the first step after the phage meets a suitable host is attachment to the cell surface, followed by injection of the viral genome into the host. This binding to receptors lets the virus inject its DNA (or RNA) so the host’s machinery can be commandeered to produce viral components. After the genome enters, the phage uses the host to replicate and assemble new virions, ultimately causing the cell to burst and release the progeny. Lysis is the final stage, not the first, while integration into the host chromosome is a feature of the lysogenic cycle, and assembly of new viruses happens later, after genome replication and protein synthesis.