Complicated diagram showing a series of events from the replication cycle of a flu virus, from the virus entering a cell, releasing its contents, replicating, and these new virus particles budding and exiting the infected cell. Anti-clockwise, from the top left corner: (1) virus attaches to cell and is endocytosed; (2) cellular lysosomes fuse with endocytosed virus and viral RNA, and proteins are released into cell; (3) viral RNA moves to nucleus of the infected cell and is transcribed into viral mRNA, which is exported into cytosol to make new viral proteins; (4) viral proteins and viral RNA self-combine to make new viral particles that bud off the cell and are released to infect more host cells.