by hindering cell wall formation, by disturbing the cell membrane, or by disrupting chemical nprocesses inside the cell. The cellular substances of bacteria are encased within a cel membrane. The cell membrane, in turn, is surrounded by a cell wall. The cell wall is rigid and prevents bacterial cell from splitting open. Some antibiotics, including penicillin,attack invasive microbes by interfering with the formation ot these cell wall. Fortunetely, these antibiotics do not affect human body cell, since animal cell do not cell walls.