viruses--

• • Non cellular entities consisting of a single type of nucleic acid (DNA/RNA) encased in protein coat (capsid)
• • Need a host cell to reproduce. Virus attaches to the host cell which it penetrates. Hijacks host’s enzymes and nutrients to make own viral proteins and nucleic acid
• • Viral material assemble into new v issues which are released from host cell and infect other cells
• • Influenza→ caused by a virus damaging human lung tissue. Most symptoms are caused by body's own immune response. Fever, cough, nasal ingestion