【英语时差8,16】抗生素（下）

（单词翻译）

Then the process begins again and those two cells divide into four. So in order to reproduce, the bacterial¹ cell has to be constantly building new cell walls. The way penicillin² and some other antibiotics⁴ work is by do stopping the growth of cell walls. These antibiotics bond to protein molecules⁵ on the existing wall and prevent the cell from adding any new material as the wall stretches. When the cell wall stretches too far, it becomes weak and eventually bursts, destroying the cell. Since animal cells don’t have cell walls, they are not affected⁶ by penicillin. Not all antibiotics work the same way, but to protect a human or animal body, an antibiotic³ has to attack bacterial cells in some specific way that won’t damage animal cells.