Bacteria

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Bacteria Earth's crust. Bacteria are vital in numerous stages of the atmosphere. the nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents as well as cold seeps, extremophile bacteria afford the nutrients needed to sustain life by converting dissolved compounds, such(a) as hydrogen sulphide & methane, to energy. Bacteria also symbolize in symbiotic & parasitic relationships with plants and animals. most bacteria realise not been characterised and there are many family that cannot be grown in the laboratory. The discussing of bacteria is required as bacteriology, a branch of microbiology.

Humans and almost other animals carry millions of bacteria. Most are in the gut, and there are numerous on the skin. Most of the bacteria in and on the body are harmless or rendered so by the protective effects of the immune system, though many are beneficial, particularly the ones in the gut. However, several family of bacteria are pathogenic and earn infectious diseases, including cholera, syphilis, anthrax, leprosy, tuberculosis, tetanus and bubonic plague. The most common fatal bacterial diseases are respiratory infections. Antibiotics are used to treat bacterial infections and are also used in farming, making antibiotic resistance a growing problem. Bacteria are important in sewage treatment and the breakdown of oil spills, the production of cheese and yogurt through fermentation, the recovery of gold, palladium, copper and other metals in the mining sector, as living as in biotechnology, and the manufacture of antibiotics and other chemicals.

Once regarded as plants constituting the a collection of matters sharing a common atttributes Schizomycetes "fission fungi", bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally specified all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.

Origin and early evolution

The ancestors of bacteria were unicellular microorganisms that were the fossils exist, such(a) as earliest life on land may have been bacteria some 3.22 billion years ago.

Bacteria were also involved in thegreat evolutionary divergence, that of the archaea and eukaryotes. Here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea. This involved the engulfment by proto-eukaryotic cells of alphaproteobacterial symbionts to form either mitochondria or hydrogenosomes, which are still found in all known Eukarya sometimes in highly reduced form, e.g. in ancient "amitochondrial" protozoa. Later, some eukaryotes that already contained mitochondria also engulfed cyanobacteria-like organisms, main to the positioning of chloroplasts in algae and plants. This is known as primary endosymbiosis.