The structure of the human cell: just about the complex

The human cell does not differ from the analogous structure in the body of other animals, if we consider only the general plan of the structure. Analyzing the structure of the human cell , cytologists distinguish two areas that differ in functions - the nucleus and the cytoplasm. Daily activity, ensuring the constant needs of a unit of all living things performs cytoplasm.

All specific functions, such as contractions of the muscle cell or the transmission of the nerve signal, are also performed by the cytoplasm. Therefore, cytoplasm differs in different types of cells . But the core of the structure is the same even in different species.

The structure of the nucleus of the cell is rather monotonous in living units of different types. There are chromatin and nucleolus lumps. Chromatin is not a chemical compound at all, it's just DNA in a "packaged" state. In chromatin, there are also RNA and a few histone proteins.

The core is often round or oval. But there are also oblong, and separated by transverse constrictions (as happens in neutrophils). Considering the structure of the human cell, it should be noted that in it there is a whole system of membranes and the interphase (out of division) core is always surrounded by a nuclear envelope. In the shell there are holes called nuclear pores. Through them, macromolecules pass into and out of the nucleus.

The internal environment of the nucleus is very different from the cell environment, this is provided by thin diaphragms of the pores, which pass only the substances needed by the core inside. So the nucleus exchanges chemical information with the cytoplasm. In the nucleolus, rRNA is formed, which is necessary for the multiplication of the cell. Often the nucleoli merge into one and a single large nucleolus can be seen in the microscope.

Nuclear Juice by chemical composition is a colloidal solution of proteins, it is poorly colored on the preparations for the electron microscope and looks like a bright area on microphotographs. This is a fairly rarefied environment, where the diffusion of metabolites is facilitated, and the genetic material can move extremely fast.

And what does the cytoplasm do? Its "duties" do not include only the organization of reproduction, everything else it can do. The structure of the human cell is such that the basis of life - oxidation, occurs precisely in the cytoplasm. It consists of many small structures, called organelles or organoids, by analogy with organs in a large organism.

Most organelles are membrane structures. Do not contain membranes only free ribosomes, centrioles, cilia and flagella (all three types of organelles are composed of microtubules), as well as fibrillar structures (microfilaments and fibrils).

The structure of the human cell is membrane in principle, that is, all the sections are covered by membranes. Mitochondria, for example, generally have two layers of membranes in which the synthesis of energy molecules - ATP as a result of cellular respiration reactions occurs. Mitochondria are unique, because they are parasites that have become symbionts. They have their genome and in general are quite independent. It is assumed that they lead the genus from bacteria.

Ribosomes, which sometimes combine in polyribosomes, are involved in the synthesis of the protein necessary for the cytoplasm. And it is very necessary not only to build structures, but also to keep the balance of osmotic pressure in the norm.

The endoplasmic reticulum is a vesicle connected with each other. Some of them have ribosomes. The protein, which they synthesize, does not float in the cytoplasm juice - cytosol, but is isolated before excretion from the cell or when used for other needs.

Apparatus Golgi - something like a pile of bags. It accumulates and sorts various substances. Proteins here acquire their final structure, and also here lysosomes are formed.

By the way, about lysosomes. They destroy unnecessary components of cells, if something is wrong with them, then accumulation diseases develop. After the death of the cell, they destroy even the environment of the dead dead unit of the living, and not only itself.

The structure of a living cell differs from the structure of the dead in the first place by the fact that the karyolysis occurs in the deceased - the decay of the nucleus and the digestion of the cell contents after the resorption of the lysosome membranes.