During the replication cycle of a lytic bacteriophage, which of the following is the second step?

• A. Attachment of the phage to the host cell surface
• B. Assembly of new phage particles
• C. Penetration of the phage nucleic acid into the host cell
• D. Release of mature phages from the host cell

Answer: (C)

Verified step by step guidance

1. Understand the lytic cycle of a bacteriophage, which typically involves a sequence of steps: attachment, penetration, biosynthesis, assembly, and release.
2. Identify the first step: Attachment, where the phage binds specifically to receptors on the host bacterial cell surface.
3. Recognize that the second step is Penetration, where the phage injects its nucleic acid (DNA or RNA) into the host cell, leaving the protein coat outside.
4. Note that after penetration, the phage nucleic acid directs the host machinery to synthesize viral components (biosynthesis), followed by assembly of new phage particles.
5. Finally, mature phages are released from the host cell, often causing cell lysis, completing the lytic cycle.