Kazakh-Russian Medical University Independent work Theme Microorganisms Prepared

Kazakh-Russian Medical University Independent work Theme: Microorganisms Prepared by: Zhantenova Indira Group: 203 B Faculty: General medicine Checked by: Kosbatyrova Nauat Almaty 2012

Microorganisms (microbes) - the collective name of a group of living organisms that are too small to be visible to the naked eye (their characteristic size - less than 0. 1 mm). The structure consists of a non-nuclear organisms (prokaryotes: bacteria, archaea) and eukaryotes: some fungi, protists, but not viruses, which are usually isolated in a separate group. Most organisms are composed of a single cell, but there are multi-cellular organisms, just as there are some single-celled microorganism, visible to the naked eye, such Thiomargarita namibiensis, members of the genus Caulerpa (are giant polikarionami). The study of these organisms do science microbiology.

In the evolution of microorganisms adapted to a variety of environmental conditions. There are bacteria that grow at 65 -75 ° C (see Thermophilic organisms), psychrophilic microorganisms growing at minus 6 ° C, halophilic microorganisms that multiply in a medium containing 25% Na. Cl, the bacteria that live in water, cooling nuclear reactors and tolerate exposure to 3 -4 million p osmophilic yeast living in honey and jam, acidophilus bacteria that multiply in acidic media at p. H 1, 0, barotolerantnye bacteria to withstand a pressure of several hundred atmospheres.

The extraordinary resistance of microorganisms to various environmental factors allows them to take the extreme limits of the biosphere: they are found in the soil of the ocean at a depth of 11 km, on the surface of ice and snow in the Arctic, Antarctic and in the mountains, in the desert soil, the atmosphere at an altitude of 20 km and etc.

Microorganisms live almost everywhere, where there is water, including hot springs, the bottom of the oceans, as well as deep within the earth's crust. They are an important link in the metabolism of ecosystems, mainly acting as decomposers, but in some ecosystems they - the only producers of biomass producers. Microorganisms that live in different environments, involved in the cycle of sulfur, iron, phosphorus, and other elements that perform the decomposition of organic substances of animal, vegetable, and abiogenic origin (methane, waxes), provide a self-cleaning water in the reservoirs.

However, not all types of microorganisms bring the man advantage. A very great number of microbial species is an opportunistic or pathogenic for humans and animals. Some micro-organisms cause damage to agricultural production, impoverish the soil with nitrogen, cause water pollution, accumulation in food poisons (eg, microbial toxins). Micro-organisms are highly adaptable to the action of environmental factors. Different microorganisms can grow at temperatures between -6 ° to +50 -75 °. Record survival at elevated temperature set archaea, some of the studied cultures that grow on nutrient media of over 110 ° C, for example, Methanopyrus kandleri (strain 116) growing at 122 ° C, a record high temperature for all known organisms

In nature habitat with the temperature there is pressure in the volcanic hot springs on the ocean floor (black smokers). Known microorganisms that flourish in disastrous for multicellular creatures levels of ionizing radiation over a wide p. H range, at 25% concentration of sodium chloride in different oxygen content up to its complete absence (anaerobic bacteria). At the same time, pathogens cause disease in humans, animals and plants. The most generally accepted theory of the origin of life on Earth suggest that protomikroorganizmy were the first living organisms appeared during evolution.

Due to the success of Biochemistry Microorganisms and especially the development of microbial genetics and molecular genetics, it was found that many of the processes of biosynthesis and energy metabolism (electron transport, citric acid cycle, the synthesis of nucleic acids, proteins, etc. ) occur in microorganisms as well as in cells of higher plants and animals. Thus. Based growth, development, reproduction, both higher and lower forms of life are a single process. In addition, the micro-organisms some specific enzyme systems and biochemical reactions, not seen in other creatures. This is based on the ability of microorganisms to degrade cellulose, lignin, chitin, petroleum hydrocarbons, keratin, wax, etc.

Microorganisms have unusually varied ways of obtaining energy. Chemoautotrophs get it from the oxidation of inorganic substances, photoautotrophic bacteria use light energy in that part of the spectrum, which is inaccessible to the higher plants, etc. Some microorganisms can assimilate molecular nitrogen (see Nitrogen-fixing microorganisms), a protein due to various carbon sources to produce many biologically active substances (antibiotics, enzymes, vitamins, growth factors, toxins, etc. )

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