Complex life of a simple cell

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Complex life of a simple cellThe beginning of a new life is given by a single fertilized egg, from which all the great many cells of the human body are formed. How many are there? According to some estimates, about 100 trillion, but I think no one can give an exact figure.

Cells are born and die. A century, for example, of a nervous and muscular one, is equal to that of a person, of erythrocytes and some other blood cells — up to a hundred days, and the epithelial cells of the intestine and skin live for only a few days.

Each of these structures invisible to the naked eye, from which, like bricks, a multicellular organism is built, in turn, is an unusually complex organism.

Take a look at the colored tab and you will see that the cell has a membrane, cytoplasm, nucleus. Cell organelles "float" in the cytoplasm: mitochondria are the energy stations of the cell; lysosomes - structures responsible for the utilization of lipids, proteins, polysaccharides; lamellar complex, or the Golgi apparatus, involved in the "packing" and removal of intracellular secretions outside the cell, and other structures.

Although the diagram shows the structure of the cell in some detail, it still does not fully correspond to reality, because it does not convey the main property of a living cell - movement. This movement can be observed using cinematographic filming. Sometimes cell motility gives the impression of a boiling boil. Cytoplasm moves, sharply changing speed, sometimes stopping. The core pulsates, shrinking, then expanding, and the core rotates. It invades, capturing nutrients, water, and protrudes, releasing waste substances, the outer cell membrane. The movement reflects the vital activity of the cell, the processes continuously occurring in it. The cage can be compared to an automated chemical factory, in different workshops of which a variety of products are produced. The list of chemical compounds working in a cell would amount to tens of thousands of names. Some substances are created, others disintegrate. For example, amino acids are used to build large protein molecules. In turn, when protein breaks down, amino acidswhich are recycled, etc.

Complex life of a simple cell
Schematic representation of a cell at the ultrastructural level; 1 - cell shell; 2 — cytoplasm; 3 - core; 4 - core shell; 5 - nucleolus; 6 - mitochondria; 7 - lamellar complex; 8 - lysosomes; 9 - vesicles, or vesicles, providing exchange between the cell and its environment; other structures.

An experimenter who wants to artificially synthesize the simplest protein will have to overcome considerable difficulties and take into account many factors in order to create conditions for synthesis. And the cell creates them every minute, economically using energy resources, strictly and accurately coordinating hundreds of chemical reactions. If necessary, the cell is capable of amazingly flexible adaptation - adapting to various circumstances, changing the nature and course of intracellular processes.

Special molecular structures of membranes are actively involved in the adaptation processes - receptors that perceive irritations from the environment surrounding the cell.

Cell receptors are proteins that protrude on the surface of the cell membrane and have the ability to move along it. The degree of their mobility depends on the molecular structure of the receptor, the type of cell and the stage of its life cycle. So, receptors of freely moving cells, say, lymphocytes, have high mobility along the membrane, and receptors, for example, epithelial cells, are much less mobile. In other words, this property is primarily determined by the specific function of each cell.

The method of transferring information from the receptor to the cell organelles has not yet been specified, but the result is already known. Its essence is that all metabolic processes are enhanced in the cell; protein synthesis is activated, permeability for nutrients and metabolic products is increased, secretion and other functions are activated.

Today, specific receptors have been identified even in individual cell organelles, for example, in mitochondria, but so far only that they exist is known about them.

Discovered over 300 years ago, the cell never ceases to amaze scientists.

Complex life of a simple cell
Cells of the human body: I ​​- epithelial cell, 2 - erythrocyte, 3 - lymphocyte, 4 - neutrophil, 5 - eosinophil, 6 - fibroblast, 7 - macrophage, 8 - collagen fibers, 9 - osteocyte (bone tissue cell), 10 - cell smooth muscle, II - striated muscle cell, 12 - nerve cell.

Now morphologists, biologists, genetics, immunologists, physicists, chemists, cybernetics are engaged in deciphering its secrets ... Perhaps you cannot list all the "interested persons". And this alone does not speak about how important everything connected with the cell is!

The cell is the stage of cognition of the processes taking place in the body. Of course, the function of a multicellular organism is immeasurably more complex than the life of an individual cell. And yet it is from the work of individual cells that, for example, the activity of the central nervous system, surprising in complexity, is formed; colossal work is carried out by the cellular ensembles that make up the heart muscle, etc.

The health of a person ultimately depends on the state of cells, therefore most diseases can be considered as diseases of cells.

For example, malformations are associated with breakdowns of the intracellular mechanism. When one has to observe cell division, one always admires the accuracy, clarity of the change in the patterns of the so-called mitosis - the divergence and alignment of chromosomes, carriers of hereditary information. But sometimes the well-oiled mechanism of division and divergence of chromosomes does not work, and if these violations occur in the germ cells, malformations of varying severity arise. What forces govern the process of mitosis is still not entirely clear. A lot of research work is being carried out in this direction, the success of which depends on the prevention and treatment of congenital malformations.

The so-called pancreatic cholera is based on the uncontrollable growth of endocrine cells of the small intestine. They secrete a large amount of hormones - secretin, enterogastron, as a result of which the secretion of fluid increases in the small intestine and uncontrollable diarrhea occurs.

If vascular cells lose their ability to destroy and expel cholesterol, there is a threat cardiovascular disease, especially atherosclerosis.

A change in the structure of the respiratory pigment hemoglobin contained in red blood cells - erythrocytes, entails a decrease in its ability to bind and transport oxygen to tissues and organs. The consequence is oxygen starvation, which is manifested by both growth retardation and cyanosis of the skin, and a decrease in muscle activity, and heart failure.

Complex life of a simple cell
The life cycle of a cell (division, preparation for reproduction, growth, etc.) is indicated by single arrows. When a cell loses its ability to divide, it grows old and dies (double arrows). Premature cell death can occur at any stage (dotted arrows) when exposed to harmful agents.

If lysosomes (carriers of a huge number of various enzymes) of brain cells do not contain an enzyme that digests fat, then it accumulates in the lysosomes, and the so-called Tay-Sachs disease develops, leading to dementia and paralysis.

The most pressing problem of modern medicine, such as oncological diseases, is also associated with violations of intracellular processes. A cancer cell is a cell, the organelles of which, due to one reason or another, have changed their functions, it is a degenerated cell, “mad”.In such cells, exchange occurs uncontrollably and, most importantly, their genetically programmed ordered division is disrupted; they begin to divide uncontrollably, growing into a tumor.

Finally, the cell is associated with the development of methods for the early diagnosis of various diseases, as well as the search for new drugs ...

It seems that already from the above examples it is obvious that a detailed study of the cell and its functions allows solving problems on which the further development of modern medicine depends. And science and practice.

V. A. Shakhlamov


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