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In comparison to eukaryotes, the intracellular features of the bacterial cell are extremely simple. Bacteria do not contain organelles in the same sense as eukaryotes. Instead, the chromosome and perhaps ribosomes are the only easily observable intracellular structures found in all bacteria. There do exist, however, specialized groups of ...
Some bacteria have escape reactions allowing them to back away from stimuli that might harm or kill. This is fundamentally different from navigation or exploration, since response times must be rapid. Escape reactions are achieved by action potential-like phenomena, and have been observed in biofilms as well as in single cells such as cable ...
Bacillota (synonym Firmicutes) is a phylum of bacteria, most of which have gram-positive cell wall structure. [2] The renaming of phyla such as Firmicutes in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature.
Spiral bacteria are another major bacterial cell morphology. [2] [30] [31] [32] Spiral bacteria can be sub-classified as spirilla, spirochetes, or vibrios based on the number of twists per cell, cell thickness, cell flexibility, and motility. [33] Bacteria are known to evolve specific traits to survive in their ideal environment. [34]
The term "bacteria" was traditionally applied to all microscopic, single-cell prokaryotes. However, molecular systematics showed prokaryotic life to consist of two separate domains, originally called Eubacteria and Archaebacteria, but now called Bacteria and Archaea that evolved independently from an ancient common ancestor. [5]
Bacteria in Cytophagales are all Gram-negative and non-spore forming. [10] [4] [11] They are non-flagellated, but move by exhibiting a gliding or flexing motion. Cytophagales are all unicellular, with rod-shaped cells that can differ significantly in shape. [10] Cells can be short or long, delicate or stout, and have tapering or rounded ends.
Bacteria within the Deinococcota group may also exhibit Gram-positive staining behavior but contain some cell wall structures typical of Gram-negative organisms. Imbedded in the Gram-positive cell wall are polyalcohols called teichoic acids , some of which are lipid-linked to form lipoteichoic acids .
For the bacterial cells bounded by a single cell membrane, the term monoderm bacteria has been proposed. [6] [10] In contrast to gram-positive bacteria, all typical gram-negative bacteria are bounded by a cytoplasmic membrane and an outer cell membrane; they contain only a thin layer of peptidoglycan (2–3 nm) between these membranes.