Antibiotic Resistance: Understanding and Responding to an Emerging Crisis

Appendix B. Microbial Life Forms

Bacteria Lack Nuclei and Other Organelles

Bacteria cause some of our most notorious infectious diseases: plague, typhus, tuberculosis, and cholera are entries on a long list. These microbes are minute, single-celled organisms that contain all the information needed to reproduce. Bacteria reproduce by binary fission (splitting apart). DNA is duplicated and pulled to separate halves of the cell; then a ring forms in the cell wall, much like a ring on your finger. The ring gets tighter and tighter until it pinches the cell in two. After cell division, the two daughter cells grow until they, too, divide in half. Thus, the number of cells in a bacterial culture increases by doubling: 1, 2, 4, 8, 16, 32, 64, and so ...