Final answer:
A permissive cell describes a host cell that actively participates in a pathogen's life cycle and permits replication. Viruses use these cells, attaching via specific receptors and exploiting the cell's machinery for replication, which can cause cytopathic effects such as cell lysis or apoptosis. Different survival strategies are employed by pathogens to multiply within these cells.
Step-by-step explanation:
The term that describes a host cell that actively participates in a pathogen's life cycle, serving as a site for multiplication or completing its life cycle, is a permissive cell. Viruses, which are obligate, intracellular parasites, require a specific type of permissive cell that allows replication. These cells must express a particular surface molecule known as the viral receptor for the virus to attach.
After attachment, the virus uses the host cell's machinery to replicate its genetic material and produce new viruses. The interaction with intracellular pathogens like viruses can lead to cell damage through cytopathic effects, which include cell lysis or apoptosis (programmed cell death). Different pathogens use various strategies to survive and multiply within permissive host cells.
Some, like phagocytes which engulf pathogens through phagocytosis, avoid destruction by lysing the phagosome or preventing its fusion with lysosomes, thereby evading the host's immune defenses. Other pathogens may incorporate their genetic material into the host cell's genome, as seen with temperate phages, and replicate along with the cell's own DNA until conditions trigger the production of new virions.