Final answer:
Viruses like influenza envelop themselves in host-derived membranes, which helps them to evade the immune system and keeps the host cell alive for continued replication. This envelope facilitates the infection of new cells and prolongs the production of viral progeny.
Step-by-step explanation:
Enveloped viruses, such as the influenza virus, utilize host-derived membranes to cloak themselves, aiding proliferation. By budding off from the host cell with an envelope consisting of the cell's plasma membrane, the virus acquires a lipid bilayer shield that harbors both host and viral proteins. This viral envelope not only mimics the host cell membrane, allowing for an improved evasion of the host's immune system, but also ensures that the host cell remains alive, continuing as a factory for viral replication. Maintaining the host cell's integrity is essential since the cell is an obligate tool for the virus's replication; it provides the necessary substances and machinery for the virus to manufacture more progeny.
Viral envelopes aid in the attachment and penetration of subsequent host cells, as the host-derived membrane on the virus can readily fuse with the membranes of new host cells, facilitating the process of infection. The resulting ability to enter cells without being detected as foreign particles enables the viruses to avoid immediate destruction by the host's immune system. This invasion stealth strategy grants viruses more time to replicate and spread before the immune system can mount an effective response. Ultimately, the survival of the host cell provides a continuous source of new viruses, allowing prolonged infection and maximizing the chances of transmission.