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| Most bacterial cell walls contain this; a network of modified-sugar polymers crosslinked by short polypetptides. This molecular fabric encloses the entire bacterium and anchors other molecules that extend from its surface. |
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| technique developed by Hans Christian Gram, scientists can classify many bacterial species int 2 groups based on differences in cell wall composition. |
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| bacteria that have simpler walls with a relatively large amount of peptidoglycan. |
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| bacteria that have less peptidoglycan and are structurally more complex, wiht an outer membrane that contains lipopolysaccharides (carbohydrates bonded to lipids). |
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| covers the cell wall of prokaryotes; it is a sticky layer of polysaccharide or protein. It enables prokaryotes to adhere to their substrate or to other individuals in a colony. It can also shield pathogenic prokaryotes from attacks by their host's immune system. |
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| allows prokaryotes to stick to their substrate or to each other by these hairlike appendages. Usually more numerous and shorter than PILI. |
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| in a uniform envrionment, flagellated prokaryotes may move randomly. In a heterogeneous environment, many prokaryotes exhbit taxis: movement toward or away from a stimulus. |
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| place in which the prokaryotic chromosome is located. |
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| these are smaller rings of DNA; most consists of only a few genes. These genes provide resistance to antibiotics, direct the metabolism of rarely encountered nutrients, or have other such "contingency" functions. Plasmids can increase a prokaryote's chance of survival. It replicates independently of the main chromosome. |
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| some bacteria can form these kind of resistant cells when an essential nutrient is lacking in the environment. |
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| Photosynthetic organism that capture light energy and use it to drive the synthesis of organic compounds from CO2. |
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| need only CO2 as a carbon source. Insead of using light for energy, they oxidize inorganic substances, such as hydrogen sulfide(H2S), ammonia(NH3), or ferrous ions(Fe2+). This mode of nutrition is unique to certain prokaryotes. |
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| Use light for energy but must obtain their carbon in organic form. |
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| must consume organic molecules for both energy and carbon. This mode is found in prokaryotes as well as protists, fungi, animals, and even some parasitic plants. |
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| Use O2 for cellular respiration and cannot grow without it. |
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| Use O2 if it is present but can also grow by fermentation in an anaerobic environment. |
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| poisoned by O2. Some live exclusively by fermentation; others extract chemical energy by ANAEROBIC RESPIRATION. |
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| substances other than O2, such as nitrate ions(NO3-) or sulfate ions(SO4 2-) accept electrons at the "downhill" end of electron transport chains. |
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| certain prokaryotes can convert atmospheric nitrogen(N2) to ammonia(NH3). The cells can then incorporate this "fixed" nitrogen into amino acids and other organic molecules. Require only light, CO2, N2, water and some minerals to grow. |
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| Cells in a colony secrete signaling molecules that recruit nearby cells, causing the colony to grow. The cells also produce proteins that adhere the cells to the substrate and to one another. Channels in the biofilm allow nutrients to reach cells in the interior and wastes to be expelled. |
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| organisms that are "lovers" of extreme conditions |
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| thrive in very hot environments. |
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| live in highly saline environments. |
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| named for the unique way the obtain energy: they use CO2 to oxidize H2, releasing methane as a waste product. Among strict anaerobes, they are poisoned by O2. |
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| these chemoheterothrophic prokaryotes break down corpses, dead vegetation, and waste products, theryby unlocking supplies of carbon, nitrogen, and other elements. |
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| An ecological relationship between organisms of different species that are in direct contact. |
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| the larger of the two symbiotic organisms |
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| The smaller of the symbiotic organisms. |
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| symbiotic relationship in which both symbiotic organisms benefit. |
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| symbiotic relationship in which one organism benefits while neither harming nor helping the other in any significant way. (this relationship is rare in nature) |
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| symbiotic relationship in which one organism, the PARASITE, benefits at the expense of the host. |
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| proteins secreted by prokaryotes. Exotoxins can produce disease even if the prokaryotes that manufacture them are not present. |
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| lipopolysaccharide components of the outer membrane of gram-negative bacteria. Differ from Exotoxins, in that they are released only when the bacteria die and their cell walls break down. |
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| the use of organisms to remove pollutants from soil, air, or water. |
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| Rapid reproduction and horizontal gene transfer facilitate the eolution of prokaryotes in changing environments. |
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