RT Book, Section A1 Levinson, Warren A1 Chin-Hong, Peter A1 Joyce, Elizabeth A. A1 Nussbaum, Jesse A1 Schwartz, Brian SR Print(0) ID 1175823979 T1 Structure of Bacterial Cells T2 Review of Medical Microbiology & Immunology: A Guide to Clinical Infectious Diseases, 16e YR 2020 FD 2020 PB McGraw Hill PP New York, NY SN 9781260116717 LK accessmedicine.mhmedical.com/content.aspx?aid=1175823979 RD 2024/03/29 AB Bacteria are classified by shape into three basic groups: cocci, bacilli, and spirochetes (Figure 2–1). The cocci are round, the bacilli are rods, and the spirochetes are spiral-shaped. Some bacteria are variable in shape and are said to be pleomorphic (heterogeneous shape). The shape of a bacterium is determined by its rigid cell wall. The microscopic appearance of a bacterium is one of the most important criteria used in its identification.