Influenza virus breaking out of a cell, illustration. Influenza viral proteins (purple) and RNA (red-purple) are distinguished from human cell proteins (blue). The virus takes the human cell membrane as an envelope, with structures on the membrane surface including hemagglutinin, neuraminidase and the M2 ion channel. M1 proteins build a capsid that encloses the ribonucleoprotein particles that carry the viral genetic information. This process of budding from and bursting out of a cell will kill the cell that was infected by the virus.