Why prokaryotes are important

The primary producers of organic carbon compounds from CO 2 are land plants and photosynthetic bacteria. A large amount of available carbon is found in living land plants. A related source of carbon compounds is humus , which is a mixture of organic materials from dead plants and prokaryotes that have resisted decomposition. Other bacteria and fungi, collectively called decomposers , carry out the breakdown decomposition of plants and animals and their organic compounds.

Most carbon dioxide in the atmosphere is derived from the respiration of microorganisms that decompose dead animals, plants, and humus. In aqueous environments and their anoxic sediments, there is another carbon cycle taking place. In this case, the cycle is based on one-carbon compounds. In anoxic sediments, prokaryotes, mostly archaea, produce methane CH 4. This methane moves into the zone above the sediment, which is richer in oxygen and supports bacteria called methane oxidizers that oxidize methane to carbon dioxide, which then returns to the atmosphere.

Figure 1. Prokaryotes play a significant role in continuously moving carbon through the biosphere. Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds to ammonia, ammonium ions, nitrate, nitrite, and nitrogen gas by many processes, many of which are carried out only by prokaryotes.

Role of Prokaryotes in Ecosystems Prokaryotes are ubiquitous: There is no niche or ecosystem in which they are not present. Prokaryotes and the Carbon Cycle Carbon is one of the most important macronutrients. Prokaryotes and the Nitrogen Cycle Nitrogen is a very important element for life because it is part of proteins and nucleic acids. Provided by : Boundless. October 16, Provided by : Wiktionary. Located at : en.

November 8, Provided by : Wikipedia. Soil bacteria, collectively called rhizobia, are able to symbiotically interact with legumes to form nodules , specialized structures where nitrogen fixation occurs Figure. Nitrogenase , the enzyme that fixes nitrogen, is inactivated by oxygen, so the nodule provides an oxygen-free area for nitrogen fixation to take place.

The oxygen is sequestered by a form of plant hemoglobin called leghemoglobin , which protects the nitrogenase , but releases enough oxygen to support respiratory activity. Symbiotic nitrogen fixation provides a natural and inexpensive plant fertilizer: It reduces atmospheric nitrogen to ammonia, which is easily usable by plants.

The use of legumes is an excellent alternative to chemical fertilization and is of special interest to sustainable agriculture , which seeks to minimize the use of chemicals and conserve natural resources.

Through symbiotic nitrogen fixation, the plant benefits from using an endless source of nitrogen: the atmosphere. The bacteria benefit from using photosynthates carbohydrates produced during photosynthesis from the plant and having a protected niche.

In addition, the soil benefits from being naturally fertilized. Therefore, the use of rhizobia as biofertilizers is a sustainable practice. Why are legumes so important? Some, like soybeans, are key sources of agricultural protein. Some of the most important legumes consumed by humans are soybeans, peanuts, peas, chickpeas, and beans. Other legumes, such as alfalfa, are used to feed cattle. Everyday Connection Microbes on the Human Body The commensal bacteria that inhabit our skin and gastrointestinal tract do a host of good things for us.

They protect us from pathogens, help us digest our food, and produce some of our vitamins and other nutrients. These activities have been known for a long time. More recently, scientists have gathered evidence that these bacteria may also help regulate our moods, influence our activity levels, and even help control weight by affecting our food choices and absorption patterns.

The Human Microbiome Project has begun the process of cataloging our normal bacteria and archaea so we can better understand these functions. A particularly fascinating example of our normal flora relates to our digestive systems. People who take high doses of antibiotics tend to lose many of their normal gut bacteria, allowing a naturally antibiotic-resistant species called Clostridium difficile to overgrow and cause severe gastric problems, especially chronic diarrhea Figure.

Obviously, trying to treat this problem with antibiotics only makes it worse. However, it has been successfully treated by giving the patients fecal transplants from healthy donors to reestablish the normal intestinal microbial community.

Clinical trials are underway to ensure the safety and effectiveness of this technique. Scientists are also discovering that the absence of certain key microbes from our intestinal tract may set us up for a variety of problems. This seems to be particularly true regarding the appropriate functioning of the immune system. There are intriguing findings that suggest that the absence of these microbes is an important contributor to the development of allergies and some autoimmune disorders.

Research is currently underway to test whether adding certain microbes to our internal ecosystem may help in the treatment of these problems, as well as in treating some forms of autism. Genetic engineering, artificial selection, antibiotic production, and cell culture are current topics of study in biotechnology and will be described in later chapters. Bioremediation has been used to remove agricultural chemicals pesticides, fertilizers that leach from soil into groundwater and the subsurface.

Certain toxic metals and oxides, such as selenium and arsenic compounds, can also be removed from water by bioremediation. The reduction of SeO 4 -2 to SeO 3 -2 and to Se 0 metallic selenium is a method used to remove selenium ions from water. Mercury is an example of a toxic metal that can be removed from an environment by bioremediation.

As an active ingredient of some pesticides, mercury is used in industry and is also a by-product of certain processes, such as battery production. Methyl mercury is usually present in very low concentrations in natural environments, but it is highly toxic because it accumulates in living tissues.

Several species of bacteria can carry out the biotransformation of toxic mercury into nontoxic forms. One of the most useful and interesting examples of the use of prokaryotes for bioremediation purposes is the cleanup of oil spills. The importance of prokaryotes to petroleum bioremediation has been demonstrated in several oil spills in recent years, such as the Exxon Valdez spill in Alaska , the Prestige oil spill in Spain , the spill into the Mediterranean from a Lebanon power plant , and, more recently, the BP oil spill in the Gulf of Mexico To clean up these spills, bioremediation is promoted by the addition of inorganic nutrients that help bacteria to grow.

Hydrocarbon-degrading bacteria feed on hydrocarbons in the oil droplet, breaking down the hydrocarbons. Some species, such as Alcanivorax borkumensis , produce surfactants that solubilize the oil, whereas other bacteria degrade the oil into carbon dioxide.

In the case of oil spills in the ocean, ongoing, natural bioremediation tends to occur if there are oil-consuming bacteria in the ocean prior to the spill. In addition to naturally occurring oil-degrading bacteria, humans select and engineer bacteria that possess the same capability with increased efficacy and the spectrum of hydrocarbon compounds that can be processed.

Under ideal conditions, it has been reported that up to 80 percent of the non-volatile components in oil can be degraded within one year of the spill.

Other oil fractions containing aromatic and highly-branched hydrocarbon chains are more difficult to remove and remain in the environment for longer periods of time. Bioremediation in the Exxon Valdez oil spill : a Cleaning up oil after the Valdez spill in Alaska, workers hosed oil from beaches and then used a floating boom to corral the oil, which was finally skimmed from the water surface. Some species of bacteria are able to solubilize and degrade the oil. Privacy Policy. Skip to main content.

Prokaryotes: Bacteria and Archaea. Search for:. Beneficial Prokaryotes. Symbiosis between Bacteria and Eukaryotes Prokaryotes fix nitrogen into a form that can be used by eukaryotes.