Who discovered the existence of cells. Cell. History of the study of cells. Cell theory. Cell theory in its modern form includes three main provisions

The first person to see cells was an English scientist Robert Hooke(known to us thanks to Hooke's law). IN 1665 trying to understand why balsa wood swims so well, Hooke began to examine thin sections of cork with the help of his improved microscope. He discovered that the cork was divided into many tiny cells, which reminded him of monastery cells, and he called these cells cells (in English cell means “cell, cell, cage”). IN 1675 Italian doctor M. Malpighi, and in 1682- English botanist N. Grew confirmed the cellular structure of plants. They began to talk about the cell as “a vial filled with nutritious juice.” IN 1674 Dutch master Anthony van Leeuwenhoek(Anton van Leeuwenhoek, 1632 -1723 ) using a microscope for the first time I saw “animals” in a drop of water - moving living organisms ( ciliates, amoebas, bacteria). Leeuwenhoek was also the first to observe animal cells - red blood cells And spermatozoa. Thus, by the beginning of the 18th century, scientists knew that under high magnification plants have a cellular structure, and they saw some organisms that were later called unicellular. IN 1802 -1808 French explorer Charles-Francois Mirbel established that all plants consist of tissues formed by cells. J. B. Lamarck V 1809 extended Mirbel's idea of ​​cellular structure to animal organisms. In 1825, a Czech scientist J. Purkinė discovered the nucleus of the egg cell of birds, and in 1839 introduced the term " protoplasm" In 1831, an English botanist R. Brown first described the nucleus of a plant cell, and in 1833 established that the nucleus is an obligatory organelle of the plant cell. Since then, the main thing in the organization of cells has been considered not to be the membrane, but the contents.
Cell theory the structure of organisms was formed in 1839 German zoologist T. Schwann And M. Schleiden and included three provisions. In 1858 Rudolf Virchow supplemented it with one more position, however, there were a number of errors in his ideas: for example, he assumed that cells were weakly connected to each other and each existed “on its own.” Only later was it possible to prove the integrity of the cellular system.
IN 1878 Russian scientists I. D. Chistyakov open mitosis in plant cells; V 1878 V. Flemming and P. I. Peremezhko discover mitosis in animals. IN 1882 V. Flemming observes meiosis in animal cells, and in 1888 E Strasburger - from plants.

18. Cell theory- one of the generally recognized biological generalizations that affirm the unity of the principle of the structure and development of the world plants, animals and other living organisms with cellular structure, in which the cell is considered as a common structural element of living organisms.

The first person to see cells was an English scientist Robert Hooke(known to us thanks to Hooke's law). IN 1665 trying to understand why balsa wood swims so well, Hooke began to examine thin sections of cork with the help of his improved microscope. He discovered that the cork was divided into many tiny cells, which reminded him of monastery cells, and he called these cells cells (in English cell means “cell, cell, cell”). IN 1675 Italian doctor M. Malpighi, and in 1682- English botanist N. Grew confirmed the cellular structure of plants. They began to talk about the cell as “a vial filled with nutritious juice.” IN 1674 Dutch master Anthony van Leeuwenhoek(Anton van Leeuwenhoek, 1632 -1723 ) using a microscope for the first time I saw “animals” in a drop of water - moving living organisms ( ciliates, amoebas, bacteria). Leeuwenhoek was also the first to observe animal cells - red blood cells And spermatozoa. Thus, already by the beginning of the 18th century, scientists knew that under high magnification plants have a cellular structure, and they saw some organisms that were later called unicellular. IN 1802 -1808 years French explorer Charles-Francois Mirbel established that all plants consist of tissues formed by cells. J. B. Lamarck V 1809 extended Mirbel's idea of ​​cellular structure to animal organisms. In 1825, a Czech scientist J. Purkinė discovered the nucleus of the egg cell of birds, and in 1839 introduced the term " protoplasm" In 1831, an English botanist R. Brown first described the nucleus of a plant cell, and in 1833 established that the nucleus is an obligatory organelle of the plant cell. Since then, the main thing in the organization of cells has been considered not to be the membrane, but the contents. Cell theory the structure of organisms was formed in 1839 German zoologist T. Schwann And M. Schleiden and included three provisions. In 1858 Rudolf Virchow supplemented it with one more position, however, there were a number of errors in his ideas: for example, he assumed that cells were weakly connected to each other and each existed “on its own.” Only later was it possible to prove the integrity of the cellular system. IN 1878 Russian scientists I. D. Chistyakov open mitosis in plant cells; V 1878 V. Flemming and P. I. Peremezhko discover mitosis in animals. IN 1882 V. Flemming observes meiosis in animal cells, and in 1888 E Strasburger - from plants.

18. Cell theory- one of the generally recognized biological generalizations that affirm the unity of the principle of the structure and development of the world plants, animals and other living organisms with cellular structure, in which the cell is considered as a common structural element of living organisms.

19. Basic principles of cell theory

Modern cell theory includes the following basic principles:

No. 1 The cell is a unit of structure, vital activity, growth and development of living organisms; there is no life outside the cell;

No. 2 A cell is a single system consisting of many elements naturally interconnected with each other, representing a certain integral formation;

No. 3 The cells of all organisms are similar in their chemical composition, structure and functions;

No. 4 New cells are formed only as a result of the division of original cells;

No. 5 Cells of multicellular organisms form tissues, and tissues form organs. The life of an organism as a whole is determined by the interaction of its constituent cells;

No. 6 Cells of multicellular organisms have a full set of genes, but differ from each other in that different groups of genes work in them, which results in morphological and functional diversity of cells - differentiation.

Development cell theory in the second half of the 19th century

Since the 1840s, the study of the cell has become the focus of attention throughout biology and has been rapidly developing, becoming an independent branch of science - cytology.

For the further development of cell theory, its extension to protists (protozoa), which were recognized as free-living cells, was essential (Siebold, 1848).

At this time, the idea of ​​the composition of the cell changes. The secondary importance of the cell membrane, which was previously recognized as the most essential part of the cell, is clarified, and the importance of protoplasm (cytoplasm) and the cell nucleus is brought to the fore (Mol, Cohn, L. S. Tsenkovsky, Leydig, Huxley), which is reflected in the definition of a cell given by M. Schulze in 1861:

A cell is a lump of protoplasm with a nucleus contained inside.

In 1861, Brücko put forward a theory about the complex structure of the cell, which he defines as an “elementary organism,” and further elucidated the theory of cell formation from a structureless substance (cytoblastema), developed by Schleiden and Schwann. It was discovered that the method of formation of new cells is cell division, which was first studied by Mohl on filamentous algae. The studies of Negeli and N.I. Zhele played a major role in refuting the theory of cytoblastema using botanical material.

Tissue cell division in animals was discovered in 1841 by Remarque. It turned out that the fragmentation of blastomeres is a series of successive divisions (Bishtuf, N.A. Kölliker). The idea of ​​the universal spread of cell division as a way of forming new cells is enshrined by R. Virchow in the form of an aphorism:

"Omnis cellula ex cellula." Every cell from a cell.

In the development of cell theory in the 19th century, contradictions arose sharply, reflecting the dual nature of cellular theory, which developed within the framework of a mechanistic view of nature. Already in Schwann there is an attempt to consider the organism as a sum of cells. This tendency receives special development in Virchow’s “Cellular Pathology” (1858).

Virchow’s works had a controversial impact on the development of cellular science:

He extended the cell theory to the field of pathology, which contributed to the recognition of the universality of cellular theory. Virchow's works consolidated the rejection of the theory of cytoblastema by Schleiden and Schwann and drew attention to the protoplasm and nucleus, recognized as the most essential parts of the cell.

Virchow directed the development of cell theory along the path of a purely mechanistic interpretation of the organism.

Virchow elevated cells to the level of an independent being, as a result of which the organism was considered not as a whole, but simply as a sum of cells.

XXcentury

Cell theory from the second half of the 19th century centuries, it acquired an increasingly metaphysical character, reinforced by Verworn’s “Cellular Physiology,” which considered any physiological process occurring in the body as a simple sum of the physiological manifestations of individual cells. At the end of this line of development of cell theory, the mechanistic theory of the “cellular state” appeared, including Haeckel as a proponent. According to this theory, the body is compared to the state, and its cells are compared to citizens. Such a theory contradicted the principle of the integrity of the organism.

The mechanistic direction in the development of cell theory was subjected to severe criticism. In 1860, I.M. Sechenov criticized Virchow’s idea of ​​the cell. Later, the cell theory was criticized by other authors. The most serious and fundamental objections were made by Hertwig, A. G. Gurvich (1904), M. Heidenhain (1907), Dobell (1911). The Czech histologist Studnicka (1929, 1934) made extensive criticism of the cellular theory.

In the 1950s, a Soviet biologist O. B. Lepeshinskaya, based on the data of her research, put forward a “new cell theory” as opposed to “Virchowianism.” It was based on the idea that in ontogenesis, cells can develop from some non-cellular living substance. A critical verification of the facts laid down by O. B. Lepeshinskaya and her adherents as the basis for the theory she put forward did not confirm the data on the development of cell nuclei from nuclear-free “living matter”.

Modern cell theory

Modern cellular theory proceeds from the fact that cellular structure is the most important form of existence of life, inherent in all living organisms, except viruses. The improvement of cellular structure was the main direction of evolutionary development in both plants and animals, and the cellular structure is firmly retained in most modern organisms.

At the same time, the dogmatic and methodologically incorrect provisions of the cell theory must be re-evaluated:

Cellular structure is the main, but not the only form of existence of life. Viruses can be considered non-cellular life forms. True, they show signs of life (metabolism, ability to reproduce, etc.) only inside cells; outside cells, the virus is a complex chemical substance. According to most scientists, in their origin, viruses are associated with the cell, they are part of its genetic material, “wild” genes.

It turned out that there are two types of cells - prokaryotic (cells of bacteria and archaebacteria), which do not have a nucleus delimited by membranes, and eukaryotic (cells of plants, animals, fungi and protists), which have a nucleus surrounded by a double membrane with nuclear pores. There are many other differences between prokaryotic and eukaryotic cells. Most prokaryotes do not have internal membrane organelles, and most eukaryotes have mitochondria and chloroplasts. According to the theory of symbiogenesis, these semi-autonomous organelles are descendants of bacterial cells. Thus, a eukaryotic cell is a system of a higher level of organization; it cannot be considered entirely homologous to a bacterial cell (a bacterial cell is homologous to one mitochondria of a human cell). The homology of all cells is thus reduced to the presence of a closed outer membrane made of a double layer of phospholipids (in archaebacteria it has a different chemical composition than in other groups of organisms), ribosomes and chromosomes - hereditary material in the form of DNA molecules that form a complex with proteins. This, of course, does not negate the common origin of all cells, which is confirmed by the commonality of their chemical composition.

The cellular theory considered the organism as a sum of cells, and the life manifestations of the organism were dissolved in the sum of the life manifestations of its constituent cells. This ignored the integrity of the organism; the laws of the whole were replaced by the sum of the parts.

Considering the cell to be a universal structural element, the cell theory considered tissue cells and gametes, protists and blastomeres as completely homologous structures. The applicability of the concept of a cell to protists is a controversial issue in cellular theory in the sense that many complex multinucleate cells of protists can be considered as supracellular structures. In tissue cells, germ cells, and protists, a general cellular organization is manifested, expressed in the morphological separation of karyoplasm in the form of a nucleus, however, these structures cannot be considered qualitatively equivalent, taking all their specific features beyond the concept of “cell”. In particular, gametes of animals or plants are not just cells of a multicellular organism, but a special haploid generation of their life cycle, possessing genetic, morphological, and sometimes environmental characteristics and subject to the independent action of natural selection. At the same time, almost all eukaryotic cells undoubtedly have a common origin and a set of homologous structures - cytoskeletal elements, eukaryotic-type ribosomes, etc.

The dogmatic cell theory ignored the specificity of non-cellular structures in the body or even recognized them, as Virchow did, as non-living. In fact, in the body, in addition to cells, there are multinuclear supracellular structures ( syncytia, simplasts) and a nuclear-free intercellular substance that has the ability to metabolize and is therefore alive. To establish the specificity of their life manifestations and their significance for the body is the task of modern cytology. At the same time, both multinuclear structures and extracellular substance appear only from cells. Syncytia and symplasts of multicellular organisms are the product of the fusion of the original cells, and the extracellular substance is the product of their secretion, i.e. it is formed as a result of cell metabolism.

The problem of the part and the whole was resolved metaphysically by the orthodox cell theory: all attention was transferred to the parts of the organism - cells or “elementary organisms”.

The integrity of the organism is the result of natural, material relationships that are completely accessible to research and discovery. The cells of a multicellular organism are not individuals capable of existing independently (the so-called cell cultures outside the body are artificially created biological systems). As a rule, only those multicellular cells that give rise to new individuals (gametes, zygotes or spores) and can be considered as separate organisms are capable of independent existence. A cell cannot be separated from its environment (as, indeed, any living systems). Focusing all attention on individual cells inevitably leads to unification and a mechanistic understanding of the organism as a sum of parts.

Cleared of mechanism and supplemented with new data, the cell theory remains one of the most important biological generalizations.

You already know that all living organisms are made up of cells. Some are from just one cell (many bacteria and protists), others are multicellular.

A cell is an elementary structural and functional unit of an organism, possessing all the basic characteristics of a living thing. Cells are able to reproduce, grow, exchange matter and energy with environment, respond to changes occurring in this environment. Each cell contains hereditary material, which contains information about all the characteristics and properties of a given organism. In order to understand how a living organism exists and works, you need to know how cells are organized and function. Many processes inherent to the body as a whole occur in each of its cells (for example, the synthesis of organic substances, respiration, etc.).

Studying the structure of the cell and the principles of its life activity cytology(from Greek kitos- cell, cell and logos – teaching, science).

The history of the discovery of the cell. Most cells are small and therefore cannot be seen with the naked eye. Today it is known that the diameter of most cells is in the range of 20 – 100 microns, and in spherical bacteria it does not exceed 0.5 microns. Therefore, the discovery of the cell became possible only after the invention of a magnifying device - a microscope. This happened at the end of the 16th - beginning of the 17th centuries. However, only half a century later, in 1665, the Englishman R. Hooke used a microscope to study living organisms and saw cells. R. Hooke cut off a thin layer of cork and saw its cellular structure, similar to a honeycomb. R. Hooke called these cells cells. Soon the cellular structure of plants was confirmed by the Italian doctor and microscopist M. Malpighi and the English botanist N. Grew. Their attention was attracted by the shape of the cells and the structure of their membranes. As a result, an idea was given of cells as “bags” or “bubbles” filled with “nutritional juice”.

A significant contribution to the study of cells was made by the Dutch microscopist A. van Leeuwenhoek, who discovered single-celled organisms - ciliates, amoebas, bacteria. He also observed animal cells for the first time - red blood cells and sperm.

IN early XIX V. Attempts are being made to study the internal contents of the cell. In 1825, the Czech scientist J. Purkinė discovered the nucleus in the egg of birds. He also introduced the concept of “protoplasm” (from the Greek. protos – first and plasma – decorated), which corresponds to today's concept of cytoplasm. In 1831, the English botanist R. Brown first described the nucleus in plant cells, and in 1833 he came to the conclusion that the nucleus is an essential part of the plant cell. Thus, at this time, the idea of ​​the structure of cells changed: the main thing in the organization of a cell began to be considered not the cell wall, but its internal contents.*

Cell theory. In 1838, the work of the German botanist Matthias Schleiden was published, in which he expressed the idea that the cell is the basic structural unit of plants. Based on the works of M. Schleiden, German zoologist and physiologist T. Schwann just a year later he published the book “Microscopic Studies on the Correspondence in the Structure and Growth of Animals and Plants,” in which he considered the cell as a universal structural component of animals and plants. T. Schwann made a number of generalizations, which were later called cell theory:

All living things are made of cells;

Plant and animal cells have a similar structure;

Each cell is capable of independent existence;

The activity of an organism is the sum of the vital processes of its constituent cells.

T. Schwann, like M. Schleiden, mistakenly believed that cells in the body arise from non-cellular matter. Therefore, a very important addition to cell theory was the principle of Rudolf Virchow: “Every cell is from a cell” (1859).

In 1874, the young Russian botanist I.D. Chistyakov first observed cell division. Later, the German scientist Walter Fleming described in detail the stages of cell division, and Oscar Hertwig and Eduard Strassburger independently came to the conclusion that information about the hereditary characteristics of a cell is contained in the nucleus. Thus, the work of many researchers confirmed and expanded the cellular theory, the foundation of which was laid by T. Schwann.

Currently, cell theory includes the following main provisions.

The great Russian physiologist I.P. Pavlov wrote:

Science is usually compared to construction. Both here and there many people work, and here and there there is a division of labor. Those who draw up the plan, some lay the foundation, others build the walls, and so on...

The “construction” of the cell theory began almost 350 years ago.

So, 1665, London, the office of physicist Robert Hooke. The owner sets up a microscope of his own design. Professor Hooke is thirty years old, he graduated from Oxford University, and worked as an assistant to the famous Robert Boyle.

Hooke was an extraordinary researcher. He did not limit his attempts to look beyond the horizon of human knowledge to any one area. He designed buildings, established “reference points” on the thermometer - boiling and freezing of water, invented an air pump and a device for determining wind force... Then he became interested in the capabilities of the microscope. Under a hundredfold magnification, he examined everything that came to hand - an ant and a flea, a grain of sand and algae. One day there was a piece of cork under the lens. What did the young scientist see? An amazing picture - correctly located voids, similar to a honeycomb. Later, he found the same cells not only in dead plant tissue, but also in living tissue. Hooke called them cells (English) cells) and described it, along with fifty other observations, in the book “Micrography”. However, it was this observation number 18 that brought him fame as the discoverer of the cellular structure of living organisms. Fame, which Hooke himself did not need. Soon he was captured by other ideas, and he never returned to the microscope, and forgot to think about cells.

But among other scientists, Hooke’s discovery aroused extreme curiosity. The Italian Marcello Malpighi called this feeling “the human itch of knowledge.” He also began to look at different parts of plants through a microscope. And I discovered that they consist of tiny tubes, sacs, and bubbles. I looked at Malpighi under a microscope and pieces of human and animal tissue. Alas, the technology of that time was too weak. Therefore, the scientist never recognized the cellular structure of the animal organism.

The further history of the discovery continued in Holland. Anthony van Leeuwenhoek (1632-1723) never thought that his name would be among the great scientists. The son of an industrialist and merchant from Delft, he also traded in cloth. So Leeuwenhoek would have lived as an inconspicuous businessman, if not for his passion and curiosity. In his spare time, he loved to grind glass to make lenses. Holland was famous for its opticians, but Leeuwenhoek achieved unprecedented skill. His microscopes, which consisted of only one lens, were much stronger than those that had several magnifying glasses. He himself claimed that he had designed 200 such devices, which provided magnification up to 270 times. But they were very difficult to use. Here’s what physicist D.S. Rozhdestvensky wrote about this: “You can imagine the terrible inconvenience of these tiny lenses. The object is close to the lens, the lens is close to the eye, there is nowhere to put the nose.” By the way, Levenguk managed to maintain visual acuity until his last days, and he lived to be 90 years old.

Through his lenses, the natural scientist saw a new world, the existence of which even desperate dreamers had no idea. What struck Leeuwenhoek most was its inhabitants—microorganisms. These tiny creatures were found everywhere: in a drop of water and a lump of earth, in saliva and even on Leeuwenhoek himself. Since 1673 detailed descriptions and the researcher sent sketches of his amazing observations to the Royal Society of London. But learned men were in no hurry to believe him. After all, their pride was hurt: “ignorant”, “layman”, “manufacturer”, and then into science. Leeuwenhoek, meanwhile, tirelessly sent new letters about his remarkable discoveries. As a result, academicians had to recognize the merits of the Dutchman. In 1680 the Royal Society elected him a full member. Leeuwenhoek became a world celebrity. People from all over came to Delft to look at the wonders discovered by his microscopes. One of the most distinguished guests was the Russian Tsar Peter I - a great hunter of everything new... Leeuwenhoek, who did not stop research, was only disturbed by numerous guests. Curiosity and excitement drove the discoverer. Over 50 years of observation, Leeuwenhoek discovered more than 200 species of microorganisms and was the first to describe the structures that, as we now know, are human cells. In particular, he saw red blood cells and sperm (in his then terminology, “balls” and “animals”). Of course, Leeuwenhoek had no idea that these were cells. But he examined and sketched in great detail the structure of the heart muscle fiber. Amazing powers of observation for someone with such primitive technology!

Antonie van Leeuwenhoek was, perhaps, the only scientist without special education in the entire history of the construction of cell theory. But all the other, no less famous cell researchers studied at universities and were highly educated people. The German scientist Caspar Friedrich Wolf (1733–1794), for example, studied medicine in Berlin and then in Halle. Already at the age of 26, he wrote the work “The Theory of Generation,” for which he was sharply criticized by his colleagues in his homeland. (After this, at the invitation of the St. Petersburg Academy of Sciences, Wolf came to Russia and stayed there until the end of his life.) What new did Wolf’s research provide for the development of cell theory? Describing “bubbles”, “grains”, “cells”, he saw them common features in animals and plants. In addition, Wolf was the first to suggest that cells may have a certain role in the development of an organism. His works helped other scientists correctly understand the role of cells.

It is now well known that the main part of the cell is the nucleus. By the way, the nucleus (in fish erythrocytes) was first described by Leeuwenhoek back in 1700. But neither he nor many other scientists who saw the nucleus attached much importance to it. Only in 1825, the Czech biologist Jan Evangelista Purkinje (1787-1869), while studying the egg of birds, drew attention to the nucleus. “A compressed spherical bubble, covered with the thinnest shell. It... is filled with productive power, which is why I called it the “germinal vesicle,” the scientist wrote.

In 1837, Purkinje informed the scientific world of the results of many years of work: every cell of the animal and human body has a nucleus. This was very important news. At that time, only the presence of a nucleus in plant cells was known. The English botanist Robert Brown (1773-1858) came to this conclusion several years before Purkinje’s discovery. Brown, by the way, coined the term “nucleus” itself (lat. nucleus). But Purkinje, unfortunately, was unable to generalize the accumulated knowledge about cells. An excellent experimenter, he turned out to be too cautious in his conclusions.

By the middle of the 19th century. Science has finally come close to completing the building called “cellular theory.” German biologists Matthias Jakob Schleiden (1804–1881) and Theodor Schwann (1810–1882) were friends. Their destinies had a lot in common, but the main thing that united them was the “human itch for knowledge” and a passion for science. The son of a doctor, a lawyer by training, Matthias Schleiden at the age of 26 decided to radically change his destiny. He again entered the university - the Faculty of Medicine and, upon graduation, took up plant physiology. The goal of his work was to understand how cells are formed. Schleiden quite rightly believed that the leading role in this process belongs to the nucleus. But in describing the emergence of cells, the scientist, alas, was wrong. He believed that each new cell develops inside an old one. And this, of course, is not so. In addition, Schleiden thought that animal and plant cells had nothing in common. That is why it was not he who formulated the basic postulates of the cellular theory. This was done by Theodor Schwann.

Growing up in a very religious family, Schwann dreamed of becoming a clergyman. In order to better prepare for a spiritual career, he entered the Faculty of Philosophy at the University of Bonn. But soon his love for natural sciences prevailed, and Schwann moved to the Faculty of Medicine. After graduation, he worked at the University of Berlin, where he studied the structure of the dorsal chord, the main organ of the nervous system of animals from the order Cyclostomes (a class of aquatic vertebrates, which include lampreys and hagfishes). The scientist discovered the sheath of nerve fibers in humans (later called Schwann's). Schwann was engaged in serious scientific work for only five years. In the prime of his strength and fame, he unexpectedly gave up his studies, moved to small, quiet Liege and began teaching. Religion and science were never able to get along with this remarkable man.

In October 1837, a most important event for science took place in Berlin. It all happened in a small restaurant where two young men went to have a bite to eat. Years later, one of them, Theodor Schwann, recalled: “Once, when I was dining with Mr. Schleiden, this famous botanist pointed out to me the important role that the nucleus plays in the development of plant cells. I immediately remembered that I had seen a similar organ in the cells of the dorsal chord, and at the same moment I realized the extreme importance that my discovery would have if I could show that in the cells of the dorsal chord this nucleus plays the same role as the nucleus plants in the development of their cells... From that moment on, all my efforts were directed towards finding evidence of the pre-existence of the cell nucleus.”

The efforts were not in vain. Just two years later, his book “Microscopic Studies on the Correspondence in the Structure and Growth of Animals and Plants” was published. It outlined the basic ideas of cell theory. Schwann was not only the first to see in the cell what unites both animal and plant organisms, but also showed the similarity in the development of all cells.

Of course, all the scientists who erected the “structure” share the authorship with Schwann. And especially Matthias Schleiden, who gave his friend a brilliant idea. There is a well-known aphorism: “Schwann stood on Schleiden’s shoulders.” Its author is Rudolf Virchow, an outstanding German biologist (1821-1902). Virchow also owns another catchphrase: “Omnis cellula e cellula,” which is translated from Latin as “Every cell from a cell.” It was this postulate that became the triumphant laurel wreath for Schwann’s theory.

Rudolf Virchow studied the importance of the cell for the entire organism. He, who graduated from the Faculty of Medicine, was especially interested in the role of cells in diseases. Virchow's works on diseases served as the basis for new science — pathological anatomy. It was Virchow who introduced the concept of cellular pathology into the science of diseases. But in his quest he went a little too far. Representing a living organism as a “cellular state,” Virchow considered the cell to be a full-fledged personality. “A cell... yes, it is precisely a personality, moreover, an active, active personality, and its activity is... a product of phenomena associated with the continuation of life.”

Years passed, technology developed, and an electron microscope appeared, giving magnification tens of thousands of times. Scientists have been able to unravel many secrets contained in the cage. Division was described in detail, cellular organelles were discovered, biochemical processes in the cell were understood, and finally the structure of DNA was deciphered. It would seem that nothing new can be learned about the cell. And yet there is still a lot that is not understood, unsolved, and certainly future generations of researchers will lay new bricks in the building of cell science!

– an elementary structural and functional unit of all living organisms. It can exist as a separate organism (bacteria, protozoa, algae, fungi) or as part of the tissues of multicellular animals, plants and fungi.

History of the study of cells. Cell theory.

The life activity of organisms at the cellular level is studied by the science of cytology or cell biology. The emergence of cytology as a science is closely related to the creation of cell theory, the broadest and most fundamental of all biological generalizations.

The history of the study of cells is inextricably linked with the development of research methods, primarily with the development of microscopic technology. For the first time the microscope was used to study plant and animal tissues English physicist and botanist Robert Hooke (1665). While studying a section of the elderberry core cork, he discovered separate cavities - cells or cells.

In 1674, the famous Dutch explorer Anthony de Leeuwenhoek improved the microscope (magnified 270 times), discovered in a drop of water single-celled organisms. He discovered bacteria in dental plaque, discovered and described red blood cells and sperm, and described the structure of the heart muscle from animal tissues.

• 1827 - our compatriot K. Baer discovered the egg.
• 1831 - English botanist Robert Brown described the nucleus in plant cells.
• 1838 - German botanist Matthias Schleiden put forward the idea of ​​the identity of plant cells from the point of view of their development.
• 1839 - German zoologist Theodor Schwann made the final generalization that plant and animal cells have general structure. In his work “Microscopic Studies on the Correspondence in the Structure and Growth of Animals and Plants,” he formulated the cell theory, according to which cells are the structural and functional basis of living organisms.
• 1858 - German pathologist Rudolf Virchow applied the cell theory in pathology and supplemented it with important provisions:

1) a new cell can only arise from a previous cell;

2) human diseases are based on a violation of the structure of cells.

Cell theory in its modern form includes three main provisions:

1) cell - the elementary structural, functional and genetic unit of all living things - the primary source of life.

2) new cells are formed as a result of the division of previous ones; A cell is an elementary unit of living development.

3) the structural and functional units of multicellular organisms are cells.

Cell theory has had a fruitful influence on all areas of biological research.