Condition for hundreds of years but once rehydrated

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Unformatted text preview: reds of years but once rehydrated can begin to produce bacterium again Endospore August 22 A great diversity of nutritional and metabolic adaptations have evolved in prokaryotes Can be grouped into 4 categories according to energy & carbon use (1) Phototroph - use light energy plants and algae (2) Chemotroph- energy from chemicals in environment oxidize ammonia and use as energy source (3) Autotroph- need only CO2 (inorganic) use carbon plant (4) Heterotroph- require at least one organic nutrient humans Combining the above leads to 4 major modes of nutrition (1) Photoautotrophs - Photosynthetic organisms use light energy to drive synthesis of organic cpds from CO2 (plants & algae) prokaryotes (2) Chemoautotrophs - Need only CO2, but oxidize inorganic substances for energy (H2S, NH3, Fe+2) (3) Photoheterotrophs - Use light for energy, obtain carbon in organic form limited to marine prokaryotes (4) Chemoheterotrophs - Consume organic molecules for energy & carbon (protists, fungi & animals and some parasitic plants) and humans Majority of prokaryotes are #4 - almost any organic molecule can serve as food source - petroleum Metabolic Relationships to Oxygen (1) Obligate aerobes - use O2 for cellular respiration & cannot grow without it -require oxygen -humans (2) Facultative anaerobes - use O2 if present but can grow anaerobically mollusks -or fermentation if 02 not present (3)  Obligate anaerobes - poisoned by O2 May use fermentation or anaerobic respiration Nitrogen Metabolism Nitrogen for proteins and DNA & RNA -by prokaryotes Prokaryotes are able to metabolize most nitrogenous compounds VITAL; by plants or animals cause humans cannot metabolize nitrogen Denitrify - soil nitrite (NO2- ) & nitrate (NO3-) - return N2 to atmosphere Nitrogen fixation - convert N2 to NH4+ only biomechanism that makes atmospheric N2 available to organisms fixing nitrogen and sending back into environment Metabolic Cooperation Cooperation between prokaryotes allows them to use environmental resources they could not use as individual cells. -bacterium Anabaena – photosynthesis and nitrogen fixation occur in different cells within the colony. cannot take place in oxygen but cells require; therefore isolated Photosynthetic cells Heterocyte heterocyte isolated Cooperation may occur in surface coatings known as biofilms. tooth plaqueopenings allow bacteria to go down further into surface Prokaryotes belonging to different species or even different Domains may cooperate - sulfate-consuming bacteria and methane consuming archaea. meta...
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