I have a 7 year old sister that asked me the difference between a bacteria and a virus (probably because of the coronavirus). I told her that bacteria are like microscopic robots that replicate themselves in a host organism by consuming its resources and producing a lot of toxic waste. A virus, on the other hand, is like a usb stick that plugs itself on a cell and "hack" it so the cell creates copies of the same usb stick, which would hack other cells and so on.

Since I'm not studying in biology, I'm not sure if I gave a good explanation. How good/bad do you think my analogy is?