All cells, whether they are prokaryotic or eukaryotic, have some common features. The common features of prokaryotic and eukaryotic cells are: 1  DNA, the genetic material contained in one or more chromosomes and located in a nonmembrane bound nucleoid region in prokaryotes and a membrane-bound nucleus in eukaryotes.
Penicillin antibiotics are used to treat treat urinary tract infections, upper respiratory tract infections, lower respiratory infections, skin infections, bacterial infections, gastrointestinal infections, meningitis, and pneumonia. They work by killing the bacteria that is causing the infection.
Eventually, scientists learned that penicillin kills bacteria by inhibiting their cell wall synthesis. In other words, it stops bacteria from making a strong, correctly-formed outer wall. Nowadays, there are many other antibiotics besides penicillin that also target the bacterial cell wall.