bio tin be divided into 3 groups

Three-domain system
system is composed of three domains of Carl Woese in 1990 proposed taxonomy will divided into two major categories of prokaryotes, initially called eubacteria (Eubacteria) and Archaea (Archaebacteria). Woese based on 16S rRNA sequence differences, that these two groups of eukaryotic organisms and genetic mechanisms from a common ancestor of the original evolved apart, so will all the three designated as a class, as a higher than industry classification system, called it is feasible to evolve also rapidly misplaced taxa (eg, microsporidia). Some people think that biological roots should be within the eubacteria, many groups in real bacteria branched off before the ancient bacteria, archaea and eukaryotes late only separated from each other.
Comparison
features three domains bacteria (Bacteria) Archaea (Archaea) eukaryotes (Eukarya)

morphology and genetic structure of prokaryotic cells is covalently closed round DNA is whether there is a group of proteins without the nuclear envelope circled along a walls with no free acid in the cell wall muramic acid does no include muramic acid free
ether lipid ester linkages connecting
ester bond joining the size of the ribosome 70S 70S 80S
begin methionine methionine methionine tRNA formyl
most of the genes in intron No No Yes operon mRNA with or without hatted and poly A tail without a plasmid with a few non-ribosomal
Body of diphtheria toxin-sensitive RNA polymerase Yes Yes 1 (4 subunits) several (8 to 12 subunits each) 3 (each 12 to 14 subunits)
need transcription factor promoter structure Yes Yes -10 and -35 TATA box sequence of TATA box
physiological
no methane production without nitrogen and with or without nitrification whether there whether with or without nitrogen availability on the photosynthesis of chlorophyll a (in chloroplasts) < br> Based on the energy of rhodopsin availability of energy metabolism of inorganic nutrients (Fe, S, H2) with or without bubbles with or without poly-b-hydroxy fatty acids as carbon motes are stored at 80 ℃ over if the growth has No prokaryotes Procaryotic organism
prokaryotes (Procaryotic organism) is composed of the aboriginal cells organisms, including cyanobacteria, bacteria, archaea, actinomycetes, rickettsia, spirochetes, mycoplasma, and Chlamydia. prokaryotes has the emulating characteristics: ① nucleoplasm and cytoplasm, no membrane between the nucleus and thus no fashion; ② no genetic substance is a ring with the histone DNA twice helix (DNA) silk, does not constitute a chromosome ( Some of the major genes in prokaryotes, there is a smaller group, and out of cells can be plasmid DNA); ③ a easy way of reproduction binary fission, mitosis or meiosis-free; ④ no sex, and some species periodically through the mutual, transformation or transduction, the part of the genome from one cell to another cell of the quasi-sexual behavior (penetrate bacteria bonding); ⑤ not by the muscle the pellet, composed of actin micro-fiber system, so the cytoplasm can not stream, neither the formation of pseudo- foot, phagocytosis and other phenomena; ⑥ flagellar microtubules is not by the constitution, much less the apparatus, endoplasmic reticulum, lysosomes, vacuoles and plastids (plants), centriole (lower plants and animals) and other organelles; ⑧ units within the cell membrane system of cyanobacteria except as otherwise generally by the thylakoid membrane in vitro fold from, including oxidative phosphorylation the electron transport chain (blue bacteria in the body of the thylakoid photosynthesis, other photosynthetic bacteria in the cell membrane folds of the membrane system to carry out photosynthesis; of bacteria in the cell membrane to nutrients for energy system Metabolism); ⑨ in the process of protein synthesis plays an important role in the ribosomal scattered in the cytoplasm, the ribosome sedimentation coefficient of 70S; ⑩ most prokaryotes have a unique cell wall composition and structure and so on. In short prokaryotic cell structure to eukaryotic cell structure than the much simpler.
70 years of molecular biology file show that: methanogenic bacteria, highly halophilic bacteria, the extreme heat of the Sulfolobus acid bacteria and thermophilic bacteria such as the 16S rRNA plasmid nucleotide sequence is different from most bacteria, but also from eukaryotes. In addition, the biological membrane structure, cell wall structure, coenzymes, metabolic pathways, tRNA and rRNA, with the general bacterial translation mechanisms are different. which was advocated The creature was placed under the outside of prokaryotes and eukaryotes but its ecological distribution is exceedingly roomy, physical extravaganza is also extremely heterogeneous. Some species can live in saturated salt solution; while others can survive in distilled water; some can procreate at 0 ℃; but some to 70 ℃ optimum temperature; some completely inorganic nutrients to bacteria to carbon dioxide as sole carbon source; others can only survive in living cells. line photosynthetic prokaryotes, some oxygen, and some clutch Oxygen; some PH of 10 or more in the environment to survive, some can only be approximately 1 in PH live in an environment; some only in an environment ample afford of oxygen to survive, when some bacteria Quedui oxygen extremely perceptive to toxic effects. Some can use inorganic nitrogen, but some absence to grow organic nitrogen; Some can use molecular nitrogen as the only nitrogen source.
Archaea Archaea archaeobacteria
( archaeobacteria) (can be called ancient archaea or bacteria) is a very special kind of bacteria, many living in extreme ecological conditions. has some characteristics of prokaryotes, such as the nuclear membrane and membrane system; also eukaryotic biological characteristics, such as the methionine initiation of protein synthesis, ribosomes are not sensitive to chloramphenicol, RNA polymerase and eukaryotic cells, similar to, DNA has introns and combining histone; both also have different in prokaryotic cells is also different from the characteristics of eukaryotic cells, such as: membrane lipids is not saponification; cell wall without peptidoglycan, and some protein-based, some impurity polysaccharides, and some like peptide poly sugar, but do not contain muramic acid, D-amino acids and two amino acid G.
history of the concept of Archaea
in 1977 by Carl Woese and George Fox's, because of their systems in 16SrRNA place the difference between trees and other prokaryotes. It was originally set at two prokaryotic Archaea (Archaebacteria) and true bacteria (Eubacteria) two sector or sub sector. Woese think they are two fundamentally different creatures, so re- labeled it as ancient bacteria (Archaea) and bacteria (Bacteria), these two, and eukaryotes (Eukarya) together constitute the three domains of biological systems.
archaea, bacteria and eukaryotes
in the cellular structure and metabolism, archaea, in many ways near to the other prokaryotes. However, in the gene transcription of these two chief processes in molecular biology, they are not clearly demonstrated the characteristics of bacteria, but very near to the eukaryotes. For example, archaea The translation uses eukaryotic initiation and elongation elements, and the translation process requires the TATA carton fastening eukaryotic protein and TFIIB.
archaea also has some other features. Unlike most bacteria, they are only one layer of cell membranes the lack of cell wall peptidoglycan. And, most bacteria and eukaryotic cell membrane mainly in the glyceride composition of lipids, and archaea membrane lipid composition by the glycerol ether. These differences may be the ultra high temperature adaptation. Archaea composition and formation of flagella of bacteria are also different.
rRNA sequence-based phylogenetic tree, shows a significant feud between the three can be: bacteria (Bacteria), Archaea (Archaea) and eukaryotes (Eukarya)

living environment is a lot of Archaea live in extreme environments. Some live in extremely high temperatures (often above 100 ℃), the example in the geyser or black smokers. Some live in very cold environment or high salt, acid or alkaline the water. However, archaea are also some neutrophils, and able to swamps, water and soil were found. Many methanogenic archaea live in the digestive tract of animals, such as ruminant animals, termites and humans. archaea are usually harmless to other organisms, and unknown pathogenic archaea.

single archaeal cells form 0.1 to 15 microns in diameter between the formation of some types of cell clusters or fiber, length up to 200 microns. They can have various shapes, such as spherical, rod-shaped, spiral, lobed or square. They have a variety of metabolic types. It should be noted that bacteria can use light manufacturing salt ATP , although archaea can not be like other creatures, like the use of light energy transfer to achieve the use of electronic chain of photosynthesis.
evolution and assortment
from the rRNA evolutionary tree, archaea, two types of Crenarchaeota (Crenarchaeota) and Canton Archaea (Euryarchaeota). Also the two types were determined by some environmental samples and found in 2002 by Karl Stetter of the peculiar species of archaea is satisfied (Nanoarchaeum equitans) form.
Woese that the bacteria, archaea, and true each represents a nuclear biological genetic mechanisms with a simple ancestor of biological offspring. This hypothesis is reflected in the Support for the three domains, each composed of several sectors. This classification was very popular, but in no way preoccupied of their own group of organisms that have not been universally accepted. Some biologists believe that archaea and eukaryotes arising from specialization bacteria.
relationship between archaea and eukaryotes is still an important issue. to get rid of the similarities mentioned above, many other genetic tree and the two together. in a number of ancient trees in eukaryotes from Canton bacteria from the Crenarchaeota than more recent, but the opposite conclusion biofilm chemistry. However, in some bacteria (such as Thermus gowns bacteria) found in a fungus-like genes and ancient, so that these relationships become complicated. Some people that the eukaryotes originated from a fusion of archaea and bacteria, the two were to become the nucleus and cytoplasm. This explains a lot of genetic similarity, but there are difficulties in interpretation of cell structure.
archaea are currently 22 the end of the genome has been completely sequenced, the sequencing of another 15 in progress.
representative
extremely thermophilic archaea bacteria (themophiles): can be grown in temperatures above 90 ℃ environment. such as Stanford University scientists found ancient bacteria, the optimum growth temperature of 100 ℃, 80 ℃ Following the inactivation, Germany, Steele Point (K. Stetter) study group in Italy found a family of ancient sea bacteria can live in temperatures above 110 ℃, the most appropriate temperature was 98 ℃, 84 ℃ or stop the growth down; the United States JA Baross ascertain some cavity secluded from bacteria living in the 250 ℃ environment. thermophilic bacteria a wide scope of nutrients, mostly heterotrophic bacteria, many of them able to obtain the energy of sulfur oxidation.
extremely halophilic bacteria (extremehalophiles): living in high-salinity environment, the salinity up to 25%, such as the Dead Sea and salt lakes.
extremely acidophilic bacteria (acidophiles): pH value of 1 to live in the following environment, often also thermophilic bacteria living in acidic hot water in volcanic zones, can sulfur dioxide, sulfuric acid excreted as metabolites.
extreme alkalophilic bacteria (alkaliphiles): Most live in salt lake or alkaline lakes, bottom pool, the living environment up to pH values ​​above 11.5, the optimum pH amount of 8 ~ 10.
methanogens (metnanogens): is a strictly anaerobic biology, can use CO2 to H2 oxidation, methane generation, and release energy.
CO2 +4 H2rCH4 +2 H2O + energy
appended information
dichotomy and the 3 domain methodology
what on earth there are several forms of life ? when Aristotle created biology, he will use the dichotomy divided into animal and plant biotechnology. microscopes birth led to the breakthrough of the hidden bacteria. bacterium with plants and animals in the cellular structure of the most fundamental difference is that nucleus within the animal and plant cells, the cardinal arsenal of genetic material DNA in this, and the bacteria were not nuclear, DNA separated from the cytoplasm. Because the difference between animals and plants is less than the difference between them and bacteria, sand East (E. Chatton) in 1937 intended the new biological dichotomy in that the biological into the nucleus with the nucleus of eukaryotes and prokaryotes contain. plants and animals are eukaryotes, while bacteria are prokaryotes.
1859 年 Darwin published Origin of Classification .1970's, with the evolution of molecular biology, Worcester finally obtained this significant discovery.
in the long process of evolution, every of the information in the biological cell molecules (nucleic acids and proteins) sequences are constantly undergoing mutations. Much of the message produced changes in the molecular series is promiscuous in time, relatively constant rate of evolution, which has a timer trait. Therefore, the genetic relationship between category can use their mutual characteristics of a gene with a clock or products (such as proteins) in the series to quantitatively narrate the difference. These genes or their products has become the disc of biological evolution of molecular timer (chronometer). Obviously, this recording process of molecular biological systems in idea when amplifying devices should be widely dispensed in all alive being. Based on this attention, Worcester opted because a small subunit ribosomal RNA phoned (SSU rRNA) molecules, as a molecular timer. this molecule is the intracellular protein synthesis mm machine a component of the ribosome, and protein synthesis in almost all biological life is an important facet of the activities. Thus, the SSU rRNA particle as a molecular timer is proper.
comparing from another prokaryotic and eukaryotic SSU rRNA sequence similarity, the Worcester found that the bacteria had previously been considered to represent a methane bacteria is another from the eukaryotes, but likewise different from the bacterial life fashions. catching into list the living conditions of methane bacteria may the birth and life of the natural environment on Earth is similar to such species as Worcester Archaea. Accordingly, Worcester made in 1977, bio can be divided into three groups, that, eukaryotes, eubacteria and archaea . Based on the results of the Pan-SSU rRNA phylogeny (evolutionary) tree was born then.
beyond research showed that the bifurcation of the evolutionary tree produced for the first time a true bacteria and archaea / eukaryotes a branch, archaea and eukaryotes occurred after the bifurcation. In other words, the ancient bacteria closer to eukaryotes than eubacteria.
Accordingly, in 1990 out of the three domain classification Wu Siti Theory: Biological divided eukaryotes, eubacteria and archaea three domains, the domain is defined as the classification units higher than the industry. To highlight the ancient distinction between bacteria and true bacteria, Worcester will be renamed Archaea Archaea. eubacteria renamed the bacteria. three domains theory of the archaea and eukaryotes and bacteria obtained the same taxonomic status.
from the date of birth, Worcester's theory would have been part of the three domains of people, primarily outside the field of micro-organisms against it. opposition insist that: prokaryotic and eukaryotic distinction is the most fundamental biological, evolutionary significance of the classification algorithms with; and has a wealthy variety of eukaryotic phenotype compared to differences between archaea and bacteria is a grain of truth big ample to need to change dichotomy is level. But in Jane's Genomic sequencing of methane prior to the completion of the last 20 years, the use of timers for a kind of molecular phylogenetic studies have again proven that the ancient bacteria is a unique form of life.
The first three domains theory of genomic testify
Although archaea have the above knowing, when people are faced with Jane's first complete genome Methanococcus sequence, or a surprise. Jane Methanococcus total of 1738 genes, which genes have not seen people actually accounted for 56%! In contrast, in the complete sequencing of Haemophilus influenzae bacteria (Haemophilus influenzae) and reproductive tract mycoplasma (Mycoplasma genitalium) genome only 20% of unknown genes. So people eventually achieve that the genomic level, the ancient bacteria is a new form of life.
more interesting is that Jane's Methanococcus genome, 44% of the absolute of those features or just about already known gene seems to contour the two types of ancient bacteria and other biological and evolutionary relationships between: Archaea in the production, cell division, metabolism and other aspects of bacteria similar to, and in the transcription, translation and replication side and the truth Nuclear Biological similar. In other words, a life in the sea spill wharf at the bottom of the peppery, curious action of microorganisms in terms of genetic information with people really have a (rather than with people absorbent tract bacteria) similar to the genes! praises the splendid life At the same time, many people began to cheer the terminal establishment of the three domain theory. U.S. can be concluded.
evolutionary tree of the new challenges of Worcester
suspense in Archaea seems from now on disappear, a overflow of new discoveries while filling back into muddle surrounded the people. all kinds of complete microbial genomes sequence one later another in one click of a mouse can way the database, the published 18 kinds of genome sequence, the ancient bacteria accounted for 4. adopt a more sensitive usage for the genome (including Jane's Methanococcus genome) were analyzed, with surprising results: Jane's Methanococcus genome, only 30% (instead of the before estimate of more than half) of the genes encoding as yet unknown function, which is bacterial genome similar. archaea, the mystique and thereby reducing the number of unique.
more unfavorable to the doctrine of the three domains, in Jane Methanococcus those functions can be speculated that gene product (protein), 44% had bacterial protein characteristics, as only 13% of eukaryotic proteins. In another archaea, thermophilic Bacillus alkaline methane (Methanobacterium thermoaotutrophicum) genome has a similar situation. Therefore, the comparative figures from the genomic point of view, archaea and bacteria is much smaller than the difference between the archaea differences between eukaryotes, insufficient to convince opponents of the doctrine of three domains.
more laborious to understand is the use of the same gene in different biological species phylogenetic positioning often get different results. Recently, a temperature close the boiling point in the growth of bacteria (Aquifex aeolicus) completed the genome sequence. For several genes the bacteria Phylogenetic studies show that: if a protein involved in regulation of cell division as a molecular record FtsY timer, the tug of bacteria with the Worcester branch in the evolutionary tree, a soil bacterium Bacillus subtilis is similar mm; whether an enzyme comprised in tryptophan synthesis preponderate, the bacterium belongs to ancient bacteria; and when comparing the the synthesis of bacteria and other organisms cytidine triphosphate (DNA of one of the elementary structural units) of the enzyme when they discovered that the archaea are no longer formed a detach group. It seems different genes seem to acquaint different evolutionary article. So, the ancient Bacteria can also be unique, unified life forms do?
of Saccharomyces cerevisiae is eukaryotic genome sequencing is completed, three domains theory encountered greater emergency. yeast nuclear genes, and genetic relationship of bacterial gene likened with the genetic relationship of Archaea have twice as many. It was also in the three forms of life exist in the household of 34 proteins were examined and found 17 families from the bacteria, merely 8 showed archaea and true nuclear biological kinship.
the correct evolutionary tree if the Worcester, archaea and eukaryotes differences in the evolutionary history of bacteria afterward than the differences between the two, then how can we explain the results above it?
evolutionary studies based ashore the popular cell endosymbiotic hypothesis of eukaryotic cell organelles (mitochondria, chloroplasts) production from bacteria and eukaryotes originally built in the early evolution of the symbiotic relationship. In this relationship, to invest a settled eukaryotic cell microenvironment endosymbionts (bacteria) is to invest vigor, over period, evolved among the symbiont organelles. eukaryotic nucleus may be portion of the genes of bacteria from the mitochondria, these few re-encoding genes are normally returned to mitochondrial proteins. But immediately comes from bacteria found in many nuclear genes encoding those in the cytoplasm, preferably than mitochondrial proteins melodrama a role. So, these genes comesintoseffect? Clearly, the symbiotic hypothesis is not enough to retention Wu Sri Lanka phylogenetic tree.
but Worcester ambition not lightly fall down the phylogenetic tree, assisting the hypothesis that it is still a lot. Recently, it was recommended that a new version of co-evolution of makeup took place between the different lineages reasoned by gene transmit. an organism, including ingestion, etc. can be used to obtain variant, maybe distant genetic relationship of biological genes. Worcester speculated that the ancestor in the evolution of biological form of bacteria, the three major lineages of archaea and eukaryotes, ahead life can exchange genes in the twig clear. But I trust Worcester, SSU rRNA-based phylogenetic tree is correct in general, three varieties of life forms exist.
debate proceeded three years ago, Jane's Methanococcus genome sequence was promulgated, seemed to denote with a continuation of 20 years, on life on world in the end there are several forms of the end of the argue. archaea seem to be identified as the third form of life. Now, just over three years, even the most optimistic people evolutionary tree can not anticipate the destiny of Worcester. this debate continues, however the taxonomic status of archaea have been questioned, but the ancient bacteria that still lives in the form of matchless recognition to varying degrees.
present, Archaea research is heating up international, not only because archaea bears distant more than the other two types of creatures, unknown biological processes and functions, and obliging clues to specify the law of biological evolution, but also because archaea has immeasurable biotechnology development prospects. archaea have been surprised afresh and afresh so that people can be definite that in the years to come, these unique creatures will continue to demonstrate the endless mysteries of life.
eubacteria Bacteria, eubacteria
eubacteria (Bacteria, eubacteria)
addition to all bacteria other than Archaea are understood as true bacteria. originally accustomed to represent the Archaea Archaea Archaea
domain (Archaea) is a massive class of prokaryotes. They either bacteria (eubacteria) have many similarities, while some characteristics similar to other eukaryotes.
History
the concept of Archaea in 1977 by Carl Woese and George Fox's, because they are in the 16SrRNA phylogenetic difference between trees and other prokaryotes. It was originally set at two prokaryotic Archaea (Archaebacteria) and true bacteria (Eubacteria) two sector or sub sector. Woese think they are two fundamentally different creatures, then rename it as ancient bacteria (Archaea) and bacteria (Bacteria), these two, and eukaryotes (Eukarya) together constitute the three domains of biological systems.
archaea, bacteria and eukaryotes
in cell structure and metabolism, and archaea, in many ways close to the other prokaryotes. However, in both molecular biology gene transcription the hub of the process, they are not clearly demonstrated the characteristics of bacteria, but very close to the eukaryotes. For example, archaea use of eukaryotic translation initiation and elongation factors, and the translation process requires eukaryotic TATA box binding protein in the and TFIIB.
archaea also has some other features. Unlike most bacteria, they are only an layer of the cell membrane and the lack of cell wall peptidoglycan. And, most bacteria and eukaryotes primarily by the lipid layer glyceride composition of the archaeal membrane lipid composition by the glycerol ether. These differences may be the ultra lofty temperature adaptedness. archaeal composition and formation of flagella of bacteria are also different.
habitats
many archaea are survival in extreme environments. Some live in extremely high temperatures (constantly above 100 ℃), the sample in the geyser or dark smokers. Some live in quite chilly environments or high salt, acid or alkaline water. However, archaea are also some neutrophils, and proficient to swamps, water and soil were found. Many methanogenic archaea live in the digestive tract of animals such as ruminants, termites and humans. archaea, constantly in other bio-friendly, and unknown pathogenic archaea.

single archaeal cells form 0.1 to 15 microns in diameter between the formation of some types of cell clusters or fiber widths up to 200 microns. They may have various shapes, such as spherical, rod-shaped, spiral, lobed or square. They have a variety of metabolic types. It should be famous that bacteria can use light salt manufacturing ATP, although archaea can not be favor other creatures use light energy the use of electronic transportation to effect the same chain of photosynthesis.
evolution and classification
rRNA evolutionary tree from ancient bacteria are divided into two categories, Crenarchaeota (Crenarchaeota) and wide archaea (Euryarchaeota). Another two unidentified classes by some environmental samples, respectively, and in 2002 by Karl Stetter discovered exotic species satisfied archaea (Nanoarchaeum equitans) form.
Woese that the bacteria, archaea, and eukaryotes each represent a simple genetic machinery ancestor of biological descendant. This hypothesis is reflected in the . This classification was very popular, but this motif does not itself biological ancestor is generally accepted. Some biologists believe that archaea and eukaryotes arising from specialized bacteria.
relationship between archaea and eukaryotes remains one important publish. to obtain rid of the similarities mentioned upon, many other genetic tree and the two attach. in some eukaryotic tree away from the wide Archaea Crenarchaeota than extra recent, but the biofilm chemistry concluded the inverse. However, in some bacteria, (such as bacteria Thermus robes) and antique fungus base alike genes, so namely these relationships become complex. Some folk calculate namely eukaryotes originated from a combination of archaea and bacteria , the 2 were to become the nucleus and cytoplasm. This explains a lot of genetic similarity, but there are difficulties in interpretation of cell structure.
There are currently 22 archaeal genomes have been sequenced entirely finished, another 15 of the sequencing in progress.
eukaryotic domain Eukarya
all eukaryotic cells, single cell or its nucleus of biological cells in general. including always multi-cellular creatures mm protists, animals, factories, fungi and some unicellular protists.
taxonomists tend to be divided into three domains of biological systems (tree domains system), the domain is higher than the industry classification system, which is divided into four sectors eukaryotic domain: natural biological, Fungi, plants, animals.
example: Modern man belongs to the eukaryotic domain of animals mr mr mr gates vertebrate subphylum Chordata Mammalia mr mr mr real animal subclass hominid primates mr mr mr chi is a race of people.