BLG 151 Lecture Notes - Lecture 4: Electric Motor, Nucleoid, Complex Cell
26 Dec 2019
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Document Summary
Most bacteria share fundamental traits: complex outer envelope, compact genome. Archaea like bacteria have a prokaryotic cell structure: have unique membrane and envelope structures. Nucleoid: non-membrane-bound area of the cytoplasm that contains the chromosome in the form of looped coils. Flagellum: external helical filament whose rotary motor propels the cell. No single bacterium possesses all the structures at all times some are found in certain phases of the cell"s life cycle. Gram-negative has thin peptidoglycan layer and outer membrane surrounding plasma membrane. Gram-positive has thin peptidoglycan layer surrounding plasma membrane. All cells share common chemical components: water (~70%) fundamental solvent of life, essential ions (e. g. k-, mg- phosphate ions, small organic molecules (e. g. enzyme co- factors, phospholipids, macromolecules (e. g. dna, rna, proteins) Cell composition varies with species, growth phase, and environmental conditions. Some bacteria"s also have internal membrane systems same design different lipids and proteins. The cell membrane is the structure that defies the existence of a cell.
