Final answer:
The influenza virus has a protein complex called VRNP and a lipid membrane envelope. The virus attaches to host cells through hemagglutinin (H) and neuraminidase (N) proteins. Once inside the host cell, viral RNA is replicated and new virions are formed and released.
Step-by-step explanation:
The basic structure of the influenza virus consists of a protein complex called the viral ribonucleoprotein (VRNP) and a lipid membrane envelope. The VRNP contains eight segments of single-stranded, negative RNA (vRNA), each encoding one or two proteins that support viral replication. On the outer surface of the envelope are proteins called hemagglutinin (H) and neuraminidase (N) spikes, which play important roles in the viral infectious cycle.
When the influenza virus enters a host cell, the hemagglutinin protein binds to sialic acid receptors on the host respiratory epithelial cells, facilitating endocytosis of the virus. Once inside the host cell, viral RNA is replicated by the viral RNA polymerase to form mRNA, which is translated by the host cell to produce viral proteins. Viral RNA molecules are also transcribed to produce viral genomic RNA, which assembles with viral proteins to form mature virions. The release of newly formed virions from the host cell is facilitated by the neuraminidase protein, which cleaves sialic acid receptors to allow the viruses to bud off from the infected cell.