Archaebacteria are single-celled organisms,initially not having a kernel. According to one of the theories of the origin of life, it is believed that these creatures were the first to emerge, and only then came bacteria, viruses and other organisms from them.
Archaebacteria were first identified as a separatesub-kingdom in 1977 by scientists K. Wese and J. Fox. It has been proven that their cell wall produces original enzymes and is not like the cell walls of other bacteria that have been investigated before. This discovery was made using the comparative analysis of 16S rRNA. With traditional microscopy, it is almost impossible to detect the characteristic differences between representatives of the arbacterium subregion and real bacteria. Presumably they appeared on the planet about three billion years ago, being pre-nuclear microorganisms.
All bacteria belong to the biological kingdom.prokaryotes Archaebacteria are no exception. In the biosystem, the organisms in question belong to the sub-kingdom of the same name, within which the following are distinguished:
Researchers classify this type of organism in different ways. Some people single out for them the kingdom of prokaryotes, others consider that it is more correct to refer them to a separate class of the kingdom of prokaryotes.
Archaebacteria are distinguished by metabolism, ecological and physiological features. Consider some types of representatives of this bioclass.
The most well-known methane-forming archaebacteria.These are the microorganisms with which methane is formed on our planet. They are obligate anaerobes, most often found in swamps, mud or pond, the digestive system of cattle and other ruminants, sewage treatment plants, flooded soils.
In addition, somerepresentatives of sulfur bacteria. They take part in the sulfur circulation, contribute to its oxidation and the formation of acid, which has corrosive properties. These microorganisms concentrate the chemical substance in their cells, and therefore their accumulation in certain places plays a decisive role in the process of nucleation of large sulfur sources.
Archaebacteria are not parasitic organisms,therefore, in limited quantities, they are used in medicine as a general tonic. They also contribute to the recycling of organic waste. This is the meaning of archaebacteria.
Archaebacteria are living organisms adapted to any habitat conditions, to any type of ecology. Among them are thermophiles, which are able to exist at temperatures above 110 aboutWITH.Bacteria living in diametrically opposite conditions of acidity - acidophilus. They “love” acid and live at a pH of 1. Alcaphils prefer to dwell in alkaline environments where the pH can reach 11. In addition, there are representatives among this sub-kingdom who can:
From the environment, they consume only simple organic matter. Dependence on natural conditions is minimal.
All representatives of archaea are characterized by the following features:
These are the features of the structure of archaebacteria.
All bacteria belonging to the kingdom of prokaryotes are subdivided into subarchy of Archaebacteria and Oxyphobacteria, as well as Real bacteria.
Colonies of some true bacteria canmake out with the naked eye. In form, they can be very different: cocci, spirillah, sarcina and others. The cell wall is built on the basis of a substance similar in composition to the structure of cellulose, covered with mucus from above. Its contents are separated from the wall by a membrane. Plastids and mitochondria are absent, surrounded by a membrane, which are characteristic of animal and plant organisms. Synthesis of proteins, as in eukaryotic organisms, is carried out using ribosomes.
When adverse conditions occurmost bacteria are able to form spores due to the release of part of the cytoplasm covered by the capsule. Metabolism in the cell stops, but the bacteria continue to live. They are carried by the wind, in favorable conditions, they return to active life.
Unlike bacteria, archaebacteria haveribosomes of comparable size with eukaryotes. At the same time, they both belong to heterotrophs. Some are capable of photosynthesis, but unlike plants, not due to the content of chlorophyll, but due to the presence of the so-called bacteriochlorophyll. In the process of bacterial photosynthesis, oxygen is not emitted here, like in plants. Representatives of these two classes often have flagella.
The second type mainly includescyanobacteria or blue-green algae. Archaebacteria and oxyphytobacteria are significantly different, despite the fact that both species belong to heterotrophs. In oxyphytobacteria has chlorophyll, which differs in structure. In addition, photosynthesizing pigments may also be present in this microorganism. In the sub-kingdoms of archaebacteria and oxyphytobacteria, the process of photosynthesis proceeds differently. In this case, flagella in the second is not observed. In oxyphytobacteria, in contrast to archaebacteria, the process of photosynthesis is accompanied by the release of oxygen.
Размножение у всех прокариот осуществляется about the same - by dividing the cell in half. The cell in oxyphytobacteria has a small amount of cellulose, mainly there are pectins and polysaccharides.
Из внешней среды могут существовать разные methods of obtaining energy for prokaryotes. Archaebacteria adapt to life with or without oxygen (aerobic). With anaerobic respiration, methane is produced. A number of archaea living on the seabed, in silt sediments, carry out the so-called "sulphate breathing" (sulphate reduction), during which sulphates are converted to hydrogen sulfide.
For the considered kingdoms of living organismscharacteristic chemosynthesis. By this is meant the process of oxidation of not only organic, but also inorganic compounds. Thus, hydrogen from the depths of our planet can be oxidized by sulfates, forming water and hydrogen sulfide. Sulfur in the process of chemosynthesis plays the role of both an oxidizing agent and a reducing agent.
Thus, archaebacteria are capable of carrying out the process of chemosynthesis, in which organic substances are formed due to the occurrence of redox reactions.
In addition, some representatives of thisspecies able to receive energy through fermentation. Others find sources in the electron transport chain, in which cytochromes, quinones, and ferredoxins are involved. In this case, transmembrane proton transfer occurs.
For organisms that make up the sub-kingdom under consideration, 4 types of food are typical:
Most of the metabolic reactions occur like those of Real bacteria.
Archaebacteria are ancient bacteria literally.translated from Greek. They are microorganisms with a pre-nuclear cell structure. In some properties, they differ from the Real bacteria. The greatest differences are observed between archaebacteria and oxyphobacteria. The main differences from the fact that cell walls contain pseudomurein, another sequence of bases is observed in the composition of tRNA. These organisms are adapted for existence in almost any conditions. Some of them are characterized by the process of photosynthesis without oxygen evolution, proceeding with the help of bacteriorhodopsin (bacteriochlorophyll).
