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 Cork tree 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, 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.

Vyrsova Inna Evgenievna, teacher

biology MBOU "Tolkayevskaya secondary

secondary school named after

Dmitry Grechushkin" Sorochinsky

urban district of Orenburg

Biology

Grade 10

UMC. I. B. Agafonova, V. I. Sivoglazov, V. B. Zakharov. 2011

Level of study: base

Lesson topic: “History of the study of cells. Cell theory ».

Total number of hours allocated to study the topic “Cell”: 12 lessons

Place of the lesson in the system of lessons on the topic: 1st lesson

Lesson type: lesson in discovering new knowledge

Lesson construction technology: developmental training.

The purpose of the lesson: formation of concepts of the history of the study of cells and the essence of cell theory.

Lesson objectives:

Educational: to form concepts of the history of the study of cells and the essence of cell theory.

Developmental: develop the ability to analyze, compare and draw conclusions.

Educational: Cultivate a positive attitude towards joint work and consciously achieve the goal.

Planned results:

Subject : know the concepts of the history of the study of cells and the basics of cell theory.

Metasubject : determine the goal and look for solutions, work with the textbook, express your thoughts and ideas.

Personal : show interest in new content, evaluate your own contribution to the work of the group.

Lesson technical support:

TSO (computers, video projector.)

Additional methodological and didactic support for the lesson:

1.Internet as a source of information

2. Portraits of scientists.

Methods:

Partially searchable

Forms of work: Individual, group, pair.

Organization and implementation of educational and cognitive activities.

Management aspect (degree of student independence):

Stimulation and motivation of cognitive interest: creating a situation of success, surprise, problematic issue, novelty.

Control and self-control of educational activities:

oral (individual and group);

written (completing multi-level tasks).

During the classes

I . Motivation stage.

Hello, I'm glad to see you in class. I wanted to start the lesson with words

“An amazing and mysterious world surrounds us, the inhabitants of the planet, forming a global structure - the biosphere, and we are an integral part of it. No less mysterious and in many ways still unknown is the world of an individual organism, be it a person or a bird, a mushroom or a plant. But the existence of all these worlds is based on the universal unit of all living things, the functioning of which ensures our life activity, shapes us and gives us individual traits; which gives rise to all living things and at the same time is itself a living organism.”

How can you figure out what we are talking about?

We're talking about a cell...

II . The stage of updating the material covered in grades 5-7.

A brief repetition of concepts from the “Remember!” section.

Work in pairs.

What is a cell?

How do cells differ from each other?

What scientific instrument was used to discover the cell?

What other methods of studying cells do you know?

III . Stage motivation of students' educational and cognitive activities .

People learned about the existence of cells only inXVIIV. Shortly before this, in 1590, the Dutch glass grinder Zacharias Jansen, by connecting two lenses together, first invented a primitive microscope. It was thanks to this invention that scientists were able to uncover the secret of cellular structure.

Today we will get acquainted with all the discoveries using textbook materials and the Internet.

IV. The stage of learning new material.

1. Study the material textbook pp. 24-28 and fill out the tables:

Distribute the scientists' tables into columns:

R. Brown, K. Behr, R. Virchow, C. Galen, C. Golgi, R. Hooke, C. Darwin, A. Leeuwenhoek, C. Linnaeus, G. Mendel, T. Schwann, M. Schleiden

Scientists who studied the cell

The names of the scientists who discovered the cell

The names of the scientists who studied parts of the cell

The names of the scientists who formulated the cell theory

The names of the scientists who complemented and developed the cell theory

Carry out a cross-check.

2. Fill out the table using information from the Internet.

Scientist

Contributions made to the study of the cell

3. Work in groups

1g.

What is the significance of cell theory?

2g.

Does the existence of viruses contradict the statements of the cellular theory?

4. Solving a problematic issue.

Why does the date of the birth of cytology coincide with the time of the formulation of cell theory, and not with the time of the discovery of the cell?

4. Determine which of the provisions of the cell theory belongs to R. Virchow?

A) a cell is the elementary unit of all living things.

B) every cell comes from another cell.

C) all cells are similar in chemical composition.

D) similar cellular structure of organisms is evidence of the common origin of all living things.

And now from the lesson you need to draw a conclusion:

People learned about the existence of cells after the invention of the microscope. The first primitive microscope was invented by Z. Jansen.
R. Hooke discovered cork cells.
A. Van Leeuwenhoek, having improved the microscope, observed living cells and described bacteria.
K. Baer discovered the mammalian egg.
The nucleus was discovered in plant cells by R. Brown.
M. Schleiden and T. Schwann were the first to formulate the cell theory. “All organisms consist of the simplest particles - cells, and each cell is an independent whole. In the body, cells act together to form a harmonious unity.”
R. Virchow substantiated that all cells are formed from other cells through cell division.
By the end of the 19th century. The structural components of cells and the process of their division were discovered and studied. The emergence of cytology.
Basic provisions of modern cell theory:
cell is a structural and functional unit of all living organisms, as well as a unit of development;
cells have a membrane structure;
nucleus - the main part of a eukaryotic cell;
cells reproduce only by division;
The cellular structure of organisms indicates that plants and animals have the same origin.

V. Stage of consolidation of new knowledge.
Work in pairs:
- What is the name of the science that studies the structure of cells?
- What did the success of cytology depend on?
-List the modern provisions of cell theory?

Think about what organisms

VI. Reflection.
What do you remember from the lesson?
What surprised you?
VII. Lesson summary stage.

Cognitive question
For what sciences and what was the significance of the creation of cell theory?
VIII. Homework.

§ 2.1. read, answer questions.

September 1674. Royal Society of London. A parcel with documents in Dutch has arrived. They contained descriptions of amazing creatures.

Drawings were attached to the letter

The members of the English Scientific Society, all old scientists, had never seen anything like it. This letter shocked them. Of course they didn't believe what they read.

They also had microscopes (the microscope appeared around 1600). However, they never saw the “small animals” described by Leeuwenhoek.

They decided that this unknown Dutchman was simply crazy.

Antonie van Leeuwenhoek was not a scientist. Actually, at first he sold fabrics. And like any merchant who cares about the quality of his goods, he checked them with a magnifying glass.

Leeuwenhoek was simply obsessed with lenses and magnifying glasses. As a result, he became the best lens manufacturer in Europe.

He inserted the most powerful lenses at that time into his microscope. No one could create a more powerful microscope for a century.

The small but most powerful lens of that time revolutionized science and opened the way history of cell studies.

He was an inquisitive person, so he looked at literally everything through a microscope. And water.

He wrote:

“... it’s simply wonderful... hitherto there has never been greater pleasure for my eye than watching thousands of tiny animals scurrying in a drop of water...”

Anthony Van Leeuwenhoek discovered the Microscopic Universe.

However, he did not quite correctly interpret what he saw. He decided that these microscopic animals have a heart, muscles and other organs, just like the animals of the macrocosm.

He called them “Animalcules” - microscopic animals.

This discovery might not have been noticed - Leeuwenhoek was unknown to anyone in the scientific world. Today he would be called an amateur naturalist.

Royal scientists treated the records with distrust and ordered to look into everything. At that time he was the main specialist in the study of microscopic objects.

Studying the spongy tissue of plants, Hooke introduced the term “cell” into biology.

He repeated Leeuwenhoek’s experiments with a microscope and finally achieved that he saw “small animals.”

The Royal Scientists had to admit that Leeuwenhoek was right.

This shocked them. The world around them, which seemed so well studied by them, turned out to be much more complex and surprising.

In 1680, Anthony Van Leeuwenhoek was admitted to the International Royal Scientific Society and proclaimed “Discoverer of microscopic animals,” confirmed by the corresponding certificate.

The newly minted scientist did not rest on his laurels for long and began to study... himself. The first thing he did was scrape the teeth and see new “Animalcules” - bacteria.

And in a drop of his own blood he saw round red bodies, which he called “Globules”.

Unfortunately, after this, the development of microbiology stopped for a century...

The next name in the history of cell study is Robert Brown

(yes, he is the one whose name is given to the random movement of particles)

At the end of the 18th - first half of the 19th centuries, Robert Brown decided to look inside plant cell.

He noticed that inside each cell there was a dense formation.

This was a turning point in the history of science.

Brown called this formation “ Core”.

Moreover, he proved that all cells have nuclei. This statement was documented in his work in 1830.

Later, Brown's observations will allow scientists to finally understand the structure of cells.

However, to continue studying cells, scientists had to create a more powerful microscope.

History of the study of cells. Berlin.

They found something in common everyone living beings - both plant and animal origin.

“All living things are made of cells”

It turns out that a multicellular organism is a “cooperation of cells”

M. Schleiden and T. Schwann created the cell theory

But not all of their statements turned out to be true...

They were wrong about the origin of the cells.

Schwann and Schleiden believed that cells arise spontaneously and grow like crystals from the smallest particles of inanimate matter. They claimed to have seen it happen under a microscope.

Robert Remak and Rudolf Virchow

One carried out all the necessary research, and the other... received all the laurels.

Remak set out to find out where the cells come from. In his scientific work, he described in detail cell division stages. Because he studied embryos, then traced the entire path - from two cells and a blastula to the formation of tissues, organs, and then the organism itself.

He proved that cells arise only from cells and nothing else.

Virchow was a professor of anatomy. In 1855, the scientist “made a knight’s move.” He took all the results of Remak's research, included them in his book and appropriated them for himself.

Because he was a respected professor, they listened to him.

Sadly, in the history of the study of cells, Virchow is still written about in all textbooks, and Remak, the real author of the discovery, is given only a modest place in the footnotes...

What did this discovery mean?

• What all life on earth started sometime with one cell.

• all living things form one family tree

Cell theory found a finished look

The vast majority of cells are microscopically small and cannot be seen with the naked eye. It became possible to see a cell and begin to study it only when the microscope was invented. The first microscopes appeared at the beginning of the 17th century. The microscope was first used for scientific research by the English scientist Robert Hooke (1665). Examining thin sections of cork under a microscope, he saw numerous small cells on them. Hooke called these cells, separated from each other by dense walls, cells, using the term “cell” for the first time.

In the subsequent period, which covered the second half of the 17th century, the entire 18th century. and the beginning of the 19th century. The microscope was being improved and data on animal and plant cells was accumulating. By the middle of the 19th century, the microscope had been significantly improved and much had become known about the cellular structure of plants and animals. The main materials about the cellular structure of plants at this time were collected and summarized by the German botanist M. Schleiden.

All the data obtained about the cell served as the basis for the creation of the cellular theory of the structure of organisms, which was formulated in 1838 by the German zoologist T. Schwann. Studying the cells of animals and plants, Schwann discovered that they were similar in structure, and established that the cell is a common elementary unit of structure of animal and plant organisms. Schwann outlined the theory of the cellular structure of organisms in his classic work “Microscopic studies on the correspondence in the structure and growth of animals and plants.”

At the beginning of the last century, the famous scientist, academician of the Russian Academy of Sciences Karl Baer discovered the mammalian egg and showed that all organisms begin their development from one cell. This cell is a fertilized egg, which splits, forms new cells, and from them the tissues and organs of the future organism are formed.

Baer's discovery complemented the cell theory and showed that The cell is not only a unit of structure, but also a unit of development of all living organisms.

An extremely significant addition to cell theory was the discovery of cell division. After the discovery of the process of cell division, it became quite obvious that new cells are formed by dividing existing ones, and do not arise anew from non-cellular matter.

The theory of the cellular structure of organisms also includes the most important materials for proving the unity of the origin, structure and development of the entire organic world. F. Engels highly appreciated the creation of the cellular theory, placing it in importance next to the law of conservation of energy and the theory of natural selection of Charles Darwin.

By the end of the 19th century. The microscope was improved to such an extent that it became possible to study the details of the cell structure and its main structural components were discovered. At the same time, knowledge began to accumulate about their functions in the life of the cell. The emergence of cytology, which currently represents one of the most intensively developing biological disciplines, dates back to this time.

Methods for studying cells. Modern cytology has numerous and often quite complex research methods that have made it possible to establish subtle structural details and identify the functions of a wide variety of cells and their structural components. The light microscope continues to play an exceptionally important role in cytological studies, which today is a complex, sophisticated device that provides magnification up to 2500 times. But even such a high magnification is far from sufficient to see the fine details of the cell structure, even if we consider sections 5–10 mm thick. µm 1, painted with special dyes.

A completely new era in the study of cell structure began with the invention of the electron microscope, which provides magnification of tens and hundreds of thousands of times. Instead of light, an electron microscope uses a fast flow of electrons, and the glass lenses of a light-optical microscope are replaced by electromagnetic fields. Electrons flying at high speed are first concentrated on the object under study, and then fall on a screen, similar to a television screen, on which you can either observe an enlarged image of the object or photograph it. The electron microscope was designed in 1933, and has become especially widely used for the study of biological objects in the last 10–15 years.

To be examined in an electron microscope, cells undergo very complex processing. The thinnest sections of cells are prepared, the thickness of which is 100–500 A. Only such thin sections are suitable for electron microscopic examination due to their low permeability to electrons.

Recently, chemical methods for studying cells have been used more and more. A special branch of chemistry - biochemistry - today has numerous subtle methods that make it possible to accurately establish not only the presence, but also the role of chemical substances in the life of a cell and the whole organism. Complex devices called centrifuges have been created, which develop enormous rotation speeds (several tens of thousands of revolutions per minute). Using such centrifuges, you can easily separate the structural components of a cell from each other, since they have different specific gravity. This very important method makes it possible to study separately the properties of each part of the cell.

Studying a living cell, its finest structures and functions is a very difficult task, and only a combination of efforts and colossal work of cytologists, biochemists, physiologists, geneticists and biophysicists made it possible to study its structural elements in detail and determine their role.



– 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. The microscope was first used to study plant and animal tissues by the English physicist and botanist Robert Hooke (1665). While studying a section of the elderberry core plug, he discovered separate cavities - cells or cells.

In 1674, the famous Dutch researcher Anthony de Leeuwenhoek improved the microscope (magnified 270 times) and discovered single-celled organisms in a drop of water. 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 a common 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.