Mitochondrions

Mitochondrions (mitochondriae) — an ATP synthesis organella. Their main function is connected with oxidation of organic compounds and use of the energy which is released at disintegration of these connections for synthesis of molecules of ATP. Proceeding from it, mitochondrions are called often power stations of a cage, or organellas of cellular respiration.

The term "mitochondrion" was entered Benda in 1897 for designation granular and the nitchatykh of structures in cytoplasm of different cages. Mitochondrions can be observed in living cells as they possess rather high density. In living cells of a mitochondrion can move, merge with each other, share. The form and the sizes of mitochondrions of animal cages are various, but on average their thickness about 0,5 microns, and length — from 1 to 10 microns. Calculations show that the quantity in cages strongly varies them — from single elements to hundreds.

So, in a cell of a liver they make more than 20% of total amount of cytoplasm and contain about 30 — 35% of total of protein in a cage. Surface area of all mitochondrions of a hepatic cell in 4 — 5 times more surfaces of its plasmatic membrane. Usually mitochondrions accumulate near those sites of cytoplasm where there is a need for ATP. So, are in a cardiac muscle of a mitochondrion close миофибрилл.

In spermatozoa of a mitochondrion form a spiral case round an axis of a zhgutik etc. The increase in number of mitochondrions in cages occurs by division, or budding, initial mitochondrions.

Mitochondrions has a fine-grained structure (fig. 12, B) in it sometimes thin threads (thickness about 2 — 3 nanometers) and granules about 15 — 20 nanometers in size come to light. Threads of a matriks of mitochondrions represent DNA molecules, and small granules — mitochondrial ribosomes.

It is revealed that in a matriksa of a mitochondrion the autonomous system of mitochondrial proteinaceous synthesis is localized. It is presented by molecules of own DNA, free from histones that pulls together them with DNA of bacterial cages. On these DNA there is a synthesis of molecules of RNA of different types: information, transfer (transport) and ribosomal. In a matriksa of mitochondrions formation of the ribosomes other than cytoplasm ribosomes is observed. These ribosomes participate in synthesis of a number of the mitochondrial proteins which aren't coded by a cage kernel.

Mitochondrions in cages can increase in sizes and number. In the latter case there is a division by a banner or fragmentation of initial large mitochondrions on smaller which in turn can grow and again share.

Some terms:

accumulation diseases (Xing.: diseases of deposition, a tezaurismoza) - the hereditary diseases caused by the violations of an exchange which are shown the progressing adjournment of substances of a certain type in cells of various fabrics, e.g. glikogenoza, a metachromatic leykodistrofiya, фукозидоз, etc.;

Mitochondrial diseases - the hereditary diseases (inherited from mother), caused by mutations in a mitochondrial genome; examples: Kirnsa-Seyr's syndrome (option of a mitochondrial entsefalomiopatiya), Leber's syndrome (a hereditary atrophy of optic nerves), MERRF syndrome (mioklonichesky epilepsy with so-called "fragmentary muscle fibers");

Не знайшли потрібну інформацію? Скористайтесь пошуком google:

Генерація сторінки за: 0.006 сек.