BIOM-360 Chapter Notes - Chapter 3-8, 10-12, 20, 25: Ribosomal Rna, Protoplasm, Psychrophile
25 Apr 2018
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Document Summary
Bacteria and archaea are often considered to be related because they share a common cell architecture. However, they are now known to have distinct characteristics and evolutionary lineages. Recent discoveries that challenge traditional notions of what a prokaryote is include the discovery of membrane-bound organelles in some bacteria and cytoskeletal elements in both bacteria and archaea. 3. 2bacteria are diverse but share some common features. Rods (bacilli) and cocci (spheres) are common bacterial shapes. In addition, bacteria may be comma-shaped (vibrio), spiral (spirillum and spirochetes), or filamentous; they may form buds and stalks; or they may have no characteristic shape (pleomorphic) ( figures 3. 1 and. Some cells remain together after division to form pairs, chains, and clusters of various sizes and shapes. Frequently observed bacterial cell structures include a cell wall, plasma membrane, cytoplasm, nucleoid, fimbriae, inclusions, capsule, ribosomes, and flagella ( figure 3. 6 ). Table 3. 1 summarizes the major functions of these structures.
