The big point is…drumroll… antibiotics only work on bacteria, NOT viruses.
Bacteria are much, much bigger than viruses. They are, as mentioned before, cells in their own right. However, they are different to human cells. They have different ways of doing things and different cell contents and structures. This is fortunate, because it means we can make chemicals that exploit these differences and target bacteria only, leaving human cells untouched and unharmed. For example, Penicillin, the most famous of these chemicals, exploits one of the main differences between human cells and bacterial cells: their outer shell. Human cells have a thin floppy cell membrane and bacteria have a thick cell wall. This thick cell wall provides protection for the bacteria as it enters hostile environments, like our bodies, to find sugar and nutrients. The wall needs constant maintenance by specific bacterial proteins that work round the clock building and rebuilding the wall to protect the bacteria. Penicillin stops these proteins in their tracks, letting the bacteria’s wall crumble and ‘poof!’ no more bacteria.
Penicillin and other chemicals that kill bacteria are commonly known as antibiotics. The trouble with that word is that it is not an accurate or clear enough description of what the chemicals do; which is kill bacteria.
A better term would be ANTIBACTERIALS!