Final answer:
In a phage replication cycle, a bacteriophage infects a bacterial cell, uses it to replicate, and ultimately causes its lysis, releasing new phages that can infect other cells and form plaques.
Step-by-step explanation:
During a phage replication cycle, a virus known as a bacteriophage or simply phage infects a bacterial cell. When 10 µl of a phage dilution are spread on a bacterial lawn of E. coli, the result is the infection of approximately 500 bacterial cells. Each of these infections can generate a plaque, which is a clear area on the lawn where the bacteria have been lysed (destroyed) by the phage. This process of cell destruction is part of the lytic cycle of the phage, where the phage hijacks the host cell's machinery to replicate its own components. When the phage has successfully replicated, it leads to the lysis of the host cell, releasing new phages to infect additional cells. The term lysis refers to the breaking apart of the bacterial cell, allowing the newly formed phage virions to exit and find new cells to infect, thus continuing the cycle.