Golgi Complex

The Golgi complex was discovered by Camillo Golgi in1898 year. This structure is present in the cytoplasm of virtually all eukaryotic (constituent higher organisms) cells, in particular, secretory cells in animals.

The Golgi complex. Structure.

The structure is represented by a stack of flattenedbags of membranes. They are called cisterns. This stack of bags is associated with a bubble system (Golgi bubbles). From one end of the pile of pouches constantly forms new cisterns by the fusion of bubbles that bud off from the endoplasmic reticulum (network of cavities). From the other end of the pile, from the inside, the cisterns complete their ripening and break up into bubbles again. So there is a gradual movement of cisterns in the hill to the inner side from the outer side.

In the tanks of the structure, maturation occursproteins intended for secretion, transmembrane proteins of the plasma membrane, proteins of lysosomes and others. The ripening substances move sequentially along the organelle cisterns. In them, the final clotting of proteins and their modifications takes place - phosphorylation and glycosylation.

Vegetative cells are characterized by the presence of a number of individual diktios (stacks). In animal cells there are often several stacks of tubes connected together or one large stack.

The apparatus (complex) Golgi contains fourmain departments: trans-Golgi network, cis-Golgi, trans-Golgi and medial-Golgi. An intermediate compartment (a separate region) is also attached to the structure. It is represented by the accumulation of membrane vesicles in the interval between the reticulum and cis-Golgi.

The whole apparatus is an organelle of very polymorphous (manifold). Even at different stages in the development of a single cell, the Golgi complex may look different.

The apparatus differs in its asymmetry.Located nearer to the cell nucleus of the cistern (cis-Golgi) contain the most immature proteins. To the tanks this is joined continuously membrane vesicles - vesicles. Different cisterns contain various resident enzymes (catalytic), which indicates that in them with sequestering proteins there are successively different processes.

The Golgi complex. Functions.

The tasks of the structure are chemicalmodification and transport of substances entering it. Proteins penetrating the apparatus from the endoplasmic reticulum are for the enzymes the initial substrate. After concentrating and modifying, the enzymes in the vesicles are transported to the designated site. For example, it can be the area of ​​formation of a new kidney. With the participation of cytoplasmic microtubules, the transfer process is most active.

The Golgi complex also performs the task of attaching carbohydrate groups to proteins and the subsequent use of these proteins in the construction of the lysosome membrane and cells.

Separate algae in the structure of the apparatus synthesizes cellulose fibers.

The functions of the Golgi complex are quite diverse. Among them, it should be noted:

  1. Sorting, excretion, accumulation of secretory products.
  2. Accumulation of lipid molecules and formation of lipoproteins.
  3. Completion of the modification of proteins (post-translational), namely glycosylation, sulfation and other.
  4. Formation of lysosomes.
  5. Participation in the formation of the acrosome.
  6. Polysaccharide synthesis for the formation of waxes, glycoproteins, mucus, gum, matrix substances in the cell walls of plants (pectins, hemicellulose and others).
  7. Formation of contractible vacuoles in protozoa.
  8. The formation of a cell plate in plant cells after the division of the nucleus.
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