- Viruses are always pathogens as they can only grow and reproduce within other living things (parasitic), this also means they are not living cells as they do not complete all life processes independently.
Features of viruses:
- Genetic material is in the form of DNA/RNA.
- A virus is approximately 0.01-0.1μm in length and is the smallest microbe.
- Influenza which causes flu
- HIV which causes AIDS
- A plant virus example is the tobacco mosaic virus which causes leaf discolouration