Presentation on the topic prokaryotic and eukaryotic cells. Prokaryotes and eukaryotes

“Study of the cell” - Table 2. Calculation of microscope magnification. Onion skin cells under a microscope. Types of cells. Epigraph of the lesson. Conclusions. Preparation of a microslide. Lesson plan. Main parts of the cell. Table 1. Parts of a microscope. The history of the discovery of the cell. The main parts of a cell are: membrane, cytoplasm and nucleus. All living things have a cellular structure.

“Mitosis and meiosis” - Vegetative propagation. Types of reproduction. Cell cytokinesis (photo). Chromatin clumps in the interphase nucleus. In anaphase 2, chromatids move toward the poles, which become daughter chromosomes. The spindle strands are attached to the bichromatid chromosomes. Mitosis = nuclear division + cytoplasmic division. Reproduction is the reproduction of one’s own kind, ensuring continuity and continuity of life.

“Meiosis lesson” - Meiosis. Chromosomal sex determination. Nitrogen cycle in the biosphere. Hereditary diseases. Carbon cycle in the biosphere. Plastic exchange. Metabolism. Phosphorus cycle in the biosphere. Comparison of mitosis and meiosis. Supporting notes used in lessons.

"Energy exchange" - Reactions. (Glycolysis). Movie. Solve the problem. Learning new material Consolidation. Fermentation. 1 2. The enzymatic and oxygen-free process of breakdown of organic substances in the cell is observed in bacteria. Testing. Stages of energy metabolism. Replace the highlighted part of each statement with one word.

"Biology Meiosis" - Mitosis. Meiosis. Improving visual perception of material; Formation of search skills; Objectives: Cell division. Mitosis and meiosis. Goal: Biology 9th grade.

“Cell structure and its functions” - Exocytosis. Scheme of the structure of hereditary information. The number of mitochondria in one cell ranges from a few to several thousand. An essential part of the cell, located between the plasma membrane and the nucleus. Cellular center. Chromoplasts. Organelles of movement. Mitochondria is a universal organelle that is a respiratory and energy center.

Prokaryotic cell Presentation by: Slobodchikova N.M. Biology teacher GBOU Central Educational Institution No. 14 59

Objectives: Educational - to expand and deepen knowledge about the cellular level of living matter organisms based on the study of the structural features of a prokaryotic cell; - reveal the role of bacteria. Developmental - develop the ability to find the necessary information in the text of the textbook, draw conclusions, logical thinking of students, creative abilities, biological speech skills. Educating - to cultivate the desire for knowledge.

Epigraph Our planet is home to a great variety of very different organisms, and all this diversity can be attributed either to eukaryotes or prokaryotes, the structural features of which need to be known. /Vernadsky V.I./

Levels of cellular organization Prokaryotic Eukaryotic Prenuclear Nuclear

Definition Prokaryotes (from Latin pro - before, before and Greek κάρῠον - core, nut) - organisms that, unlike eukaryotes, do not have a formed cell nucleus and other internal membrane organelles MICROBIOLOGY - the science that studies microorganisms. BACTERIOLOGY is the science that studies bacteria.

These are the most ancient organisms on Earth. How many miracles these tiny creatures conceal within themselves. (A.V. Leeuwenhoek) 1675 Anthony Van Leeuwenhoek First saw bacteria through an optical microscope and described them.

A little history 1828 Christian Ehrenberg 1850 Louis Pasteur 1905 Robert Koch 1828 Christian Ehrenberg coined the name "bacteria". In 1850, Louis Pasteur began the study of the physiology and metabolism of bacteria, and also discovered their pathogenic properties. 1905 Robert Koch formulated general principles identifying the causative agent of the disease, for which he was awarded the Nobel Prize. He suggested methods of disinfection.

Number of bacteria in 1 cm 3 of soil Forest soil on the surface Forest soil deeper than 1 m Meadow soil on the surface Meadow soil deeper than 1 m

Number of bacteria in 1cm3 of air Unventilated room City street Mountain air Sea air

Number of bacteria in 1 cm 3 of water Snow and ice Stream 100 m from the glacier Stream 5 km from the glacier Spring water

Kingdom Drobyanka Bacteria Blue-green algae

Diversity of external structure of bacterial cells spirilla vibrios bacillus cocci

Prokaryotic cell structure

Cell wall made of murein. Almost no internal membranes. Mesosomes are membrane structures formed by invagination of the plasma membrane into the cytoplasm

The primitiveness of the structure is expressed by: Lack of a formed nucleus Hereditary information is contained in one DNA molecule No organelles other than ribosomes The functions of organelles are performed by mesosomes, a durable shell

Reproduction is by dividing in two. Sporulation Stage life cycle many prokaryotes associated with surviving unfavorable conditions.

Education dispute

Sexual process. The emergence of new gene combinations – an increase in the diversity of properties

The role of bacteria in nature Bacteria in nature Participate in the formation of humus Convert humus into minerals Assimilate nitrogen from the air Pathogenic plant bacteria

Some bacteria settle in the digestive tract of herbivorous mammals and insects, ensuring the digestion of fiber.

In nature there is a process called “fermentation”. This is the breakdown of carbohydrates. Various bacteria play an important role in fermentation processes. For example, in the formation of kefir and curdled milk from milk, as well as in the fermentation of cabbage, lactic acid bacteria are very important.

The role of bacteria in human life. Pathogenic bacteria plague cholera

Disease prevention VACCINATION IMMUNITY

Comparative characteristics of cells Cell structure Prokaryotic cell Eukaryotic cell Ribosomes Golgi complex Lysosomes Mitochondria Vacuoles Cilia and flagella § 5.1 pp. 136-142

Prokaryotes and eukaryotes. There are two types of cells known in modern and fossil organisms: prokaryotic and eukaryotic. These cells differ so greatly in their structural features that two superkingdoms have been identified - prokaryotes (prenuclear) and eukaryotes (true nuclear). Intermediate forms between these largest living taxa are still unknown. The main difference between a prokaryotic cell and a eukaryotic cell is that their DNA is not organized into chromosomes and is not surrounded by a nuclear envelope. Eukaryotic cells are much more complex. Their DNA, bound to protein, is organized into chromosomes, which are located in a special formation, essentially the largest organelle of the cell - the nucleus. In addition, the extranuclear active content of such a cell is divided into separate compartments using the endoplasmic reticulum. EPS is formed by the simplest membrane. Eukaryotic cells are usually larger than prokaryotic cells.

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“Mitosis cell division” - Prophase Metaphase Anaphase Telophase. Metaphase. Anaphase. Interphase. DNA helixation occurs in the nucleus; The nucleoli disappear. Formation of the spindle, shortening of chromosomes, formation of the equatorial plate. Then mitosis (cell division) occurs and the cycle repeats. Mitosis disorders. Telophase.

“Cell of an organism” - The prokaryotic type of cellular organization preceded the eukaryotic type of cellular organization. 1. Introduction. Hypothesis. What explains the diversity of cell structure types? 3 Comparison of plant and animal cells. Working group: Kobets V., Dedova A., Fokina A., Nechaev S., Tsvetkov V., Datskevich Yu.

"Cell within a body" - The cells of most single-celled organisms contain all the parts of eukaryotic cells. Microscopes were constantly improved. Classification of cells. Cells of multicellular animals. Somatic cells Sex cells. Control questions. What components does a cell consist of? What cells do you know?

“Cell division” - Meiosis Greek “meiosis” - reduction. Late prophase. Mitosis. Mitotic cycle. Chromosomes are concentrated at opposite poles of the cell. Mitosis Greek "mitos" - thread. Biological meaning. Types of cell division. Somatic. Anaphase. Metaphase. Amitosis. Telophase. Early prophase. Sexual

“Meiosis” - Gametes with a haploid set arise from initial cells with a diploid set of chromosomes. Spermatogenesis. The second division of meiosis leads to the formation of second-order haploid spermatocytes. First division of meiosis. The basis of reproduction and individual development organisms undergo the process of cell division.

Prokaryotic cell

Bacteria are “the great gravediggers of nature” Louis Pasteur. These small organisms created life on Earth, carry out the global cycle of substances in nature, and also serve humans.

Properties Types of prokaryotes 1. Origin 2. Habitat and prevalence 3. Size 4. Shape 5. Structure of the bacterial cell 6. Metabolism, relation to oxygen 7. Nutrition 8. Reproduction 9. Sporulation 10. Role in nature 11. Human use

Origin of prokaryotes Initially appeared in an oxygen-free environment 2.5-3 billion years ago in the seas

Habitat of prokaryotes Atmosphere Hydrosphere Lithosphere Inside cells

Dimensions The sizes of bacterial cells range from 1 to 10-15 microns

Form of Cocci Diplococcus Tetracoccus

Form Streptococcus

Sarcina form Staphylococcus rods (bacillus)

Form of Spirilla Spirochetes Vibrios

The structure of a bacterial cell On the surface of bacteria, various kinds of flagella (pilli) and villi (fimbia) are often visible - organelles of movement, with the help of which they move by sliding.

Structure of a bacterial cell 1 - cell wall, 2 - outer cytoplasmic membrane, 3 - chromosome (circular DNA molecule), 4 - invagination of the outer cytoplasmic membrane, 5 - vacuoles, 6 - mesosome (outgrowth of the outer membrane), 7 - stacks of membranes in which photosynthesis is carried out, 8 - ribosome, 9 - flagella.

Structure of a bacterial cell The cell wall of prokaryotes is rigid and contains polysaccharides and amino acids. The main strengthening component is murein. The cell wall of many bacteria is covered with a layer of mucus on top. The cytoplasm is surrounded by a membrane that separates it from the inside from the cell wall.

The structure of a bacterial cell The main feature is the absence of a nucleus, limited by a membrane. Hereditary information in bacteria is contained in one chromosome. Free ribosomes are smaller than in eukaryotes; they carry out protein biosynthesis

Metabolism In relation to oxygen, prokaryotes are divided into two groups: anaerobic (not requiring oxygen); aerobic (living in an oxygen environment); some bacteria can live in both anoxic and oxygenic environments

Reproduction Bacteria have two methods of reproduction: by dividing the cell in two and by sexual

Sporulation Many bacteria are characterized by sporulation. Disputes arise when there is a lack of nutrients or when waste products accumulate in the environment, i.e. unfavorable conditions arise

Role in nature A) Bacteria destroy the remains of organic matter and produce mineralization. B) Bacteria - symbionts (E. coli), settling in the digestive tract of animals, break down cellulose into glucose, and ensure the absorption of these substances by the animal’s body, producing vitamins and other substances. C) Nitrogen-fixing (nodule) bacteria contribute to the absorption of soil nitrogen by plant roots.

Human use The production of many food and technical products is impossible without the participation of various fermentative bacteria (bifidobacteria in the figure)

Negative role of bacteria Various types of putrefactive bacteria cause food spoilage. Salmonellosis, botulism, cholera and dysentery are diseases associated with the consumption of spoiled foods. Whooping cough, tuberculosis, plague, sexually transmitted diseases, tetanus, pneumonia and many others are transmitted by airborne droplets or sexual contact.

Why did Louis Pasteur call prokaryotic organisms the great gravediggers of nature?

How do you feel when studying this topic?

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Bacteria translated from ancient Greek βακτήριον - rod. Colony of bacteria Size scale The name “bacterium” comes from the ancient Greek word “bacterion” - rod. Bacteria are the smallest of organisms with a cellular structure; their sizes range from 0.1 to 10 microns. A typical printing point can accommodate hundreds of thousands of medium-sized bacteria. Bacteria can only be seen with a microscope, which is why they are called microorganisms or microbes; microorganisms are studied by microbiology. The part of microbiology that studies bacteria is called bacteriology.

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Bacterial cells are diverse in their external structure Vibrios Spirilla Bacilli Cocci Escherichia coli Vibrio cholerae Streptococcus Based on their shape, bacteria are divided into several groups: Ball-shaped bacteria are called “cocci”. For example, staphylococci. The bacilli look like rods. For example, tuberculosis bacillus. Vibrios and spirilla are comma-shaped. For example, Vibrio cholerae. Spirilla have a spiral shape.

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About discoveries allegedly made by chance: “Happiness smiles only on a well-prepared mind” Louis Pasteur 1676 Antoni van Leeuwenhoek The science of microbiology (bacteriology) was started by the Dutch naturalist Antoni van Leeuwenhoek, who first saw bacteria and other microorganisms in a microscope, describing them. Microscopic creatures, he called them “animalcules” (little animals).

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History of the study of bacteria Christian Ehrenberg Louis Pasteur Robert Koch The name “bacteria” was introduced by Christian Ehrenberg in 1828. 2. In 1850, the French physician Louis Pasteur began the study of the physiology and metabolism of bacteria, and also discovered their pathogenic properties. Louis Pasteur was the first to develop a method of warning infectious diseases with the help of vaccinations. Vaccination is the administration of a vaccine (a special drug) to a person, thanks to which he becomes immune to a given disease. 3. In 1905, Robert Koch was awarded the Nobel Prize for his research into tuberculosis. He formulated the general principles for determining the causative agent of the disease.

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History of the study of bacteria Electron microscope 1930 S.N. Vinogradsky M.V. Beyerinck 4. The foundations of general microbiology and the study of the role of bacteria in nature were laid by M.V. Beijerink and S.N. Vinogradsky. Sergei Nikolaevich Vinogradsky is an outstanding Russian microbiologist, founder of the ecology of microorganisms and soil microbiology. Discovered chemosynthesis (1887). Martin Willem Beijerinck, discoverer of symbiotic nitrogen fixers (1888), studied soil microbiology and the relationship of microorganisms with soil fertility. One of the founders (along with S.N. Vinogradsky) of environmental microbiology. 5. The study of the structure of bacterial cells began with the invention electron microscope in 1930. 6. In 1937, E. Chatton proposed dividing all organisms according to the type of cellular structure into prokaryotes and eukaryotes. 7. And in 1961, Steinier and Van Niel finally formalized this division.

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Empire Cellular Superkingdom Prokaryotes Kingdom Drobyanka Subkingdom Archaebacteria SubkingdomBacteria SubkingdomCyanobacteria – single-layer, lipid membranes; – not sensitive to antibiotics. – double-layer membranes, lipoprotein; – sensitive to antibiotics. methane-forming bacteria, acidophilic bacteria, sulfur-aerobic bacteria. ammonifying, nostocaceous. Prokaryotes include archaebacteria, bacteria and blue-green algae (cyanobacteria). Prokaryotes are single-celled organisms that lack a structurally formed nucleus, membrane organelles, and mitosis. Archaebacteria - contain r-RNA, different in structure from both the r-RNA of prokaryotes and the r-RNA of eukaryotes. The structure of the genetic apparatus of archaebacteria (presence of introns and repeating sequences, processing, shape of ribosomes) brings them closer to eukaryotes; on the other hand, archaebacteria also have typical features of prokaryotes (absence of a nucleus in the cell, presence of flagella, plasmids and gas vacuoles, rRNA size, nitrogen fixation). Archaebacteria differ from all other organisms in the structure of their cell wall, the type of photosynthesis, and some other characteristics. Archaebacteria are capable of existing in extreme conditions (for example, in hot springs at temperatures above 100 ° C, in the ocean depths at a pressure of 260 atm, in saturated salt solutions (30% NaCl)). Some archaebacteria produce methane, others use sulfur compounds to produce energy. Apparently, archaebacteria are a very ancient group of organisms; “extreme” possibilities indicate conditions characteristic of the Earth’s surface in the Archean era. It is believed that archaebacteria are closest to the hypothetical “pro-cells” that subsequently gave rise to all the diversity of life on Earth.

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Structure of a bacterial cell Plasma membrane DNA thread inclusion flagella Cell wall Mesosomes ribosome Bacterial cells do not have a nucleus, so they are classified as prokaryotes. It turns out that the hereditary material of the bacterial cell - the DNA molecule - is closed in a ring and located among the cytoplasm, and there are also small circular DNA molecules - plasmids. The cell is surrounded by a membrane of normal structure, to the outside of which there is a cell wall. Bacterial cell walls are composed of peptidoglycan (murein) and are of two types: gram-positive and gram-negative. The Gram-positive cell wall consists exclusively of a thick layer of peptidoglycan, tightly adjacent to the cell membrane and permeated with teichoic and lipoteichoic acids. Various flagella and villi can form on the surface of the bacterial shell. The flagella perform rotational movements, due to which the bacterium moves. In 1 second, a bacterium can travel a distance 20 times greater than its own diameter! There are no vacuoles in the bacterial cell, and droplets of various substances can be located directly in the cytoplasm. An essential cell organelle is ribosomes, which ensure protein synthesis. 6. There are no membrane organelles, but the membrane can form folds called mesosomes. They can have different shapes (bag-shaped, tubular, lamellar, etc.). Enzymes are located on the surface of mesosomes.

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Reproduction The main method of bacterial reproduction is asexual reproduction: cell division in two, budding. Sexual process: Conjugation. Transduction. Transformation. The main way bacteria reproduce is asexual reproduction: cell division in two, budding. Since there is no nucleus, this division cannot be called mitosis. Binary fission: before division DNA replication occurs, the mesosome divides the cell into two. Some bacteria, under favorable conditions, are able to divide every 20 minutes. Budding: Some bacteria reproduce by budding. In this case, a bud is formed at one of the poles of the mother cell, and one of the divided nucleoids passes into it. The bud grows, turning into a daughter cell, and separates from the mother cell. Sexual process: conjugation, transduction, transformation. The sexual process of bacteria differs from the sexual process of eukaryotes in that bacteria do not form gametes and cell fusion does not occur. The sexual process involves genetic recombination. Conjugation is the unidirectional transfer of an F-plasmid from a donor cell to a recipient cell in contact with each other. In this case, bacteria are connected to each other by special F-pili (F-fimbriae), through the channels of which DNA fragments are transferred. Conjugation can be divided into the following stages: 1) unwinding of the F-plasmid, 2) penetration of one of the chains of the F-plasmid into the recipient cell through the F-pilus, 3) synthesis of a complementary chain on a single-stranded DNA template (occurs as in the donor cell (F+ ), and in the recipient cell (F-)). Transformation is the unidirectional transfer of DNA fragments from a donor cell to a recipient cell that are not in contact with each other. In this case, the donor cell either “releases” a small fragment of DNA from itself, or the DNA enters environment after the death of this cell. In any case, the DNA is actively absorbed by the recipient cell and integrated into its own “chromosome”. Transduction is the transfer of a DNA fragment from a donor cell to a recipient cell using bacteriophages.

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Formation of spores Under unfavorable conditions, the bacterium becomes covered with a dense shell, the cytoplasm is dehydrated, and vital activity almost ceases. In this state, bacterial spores can remain in a deep vacuum for hours and tolerate temperatures from –240 °C to +100 °C.

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Methods of nutrition 4. Autotrophs that do not require substances produced by other organisms include photosynthetics (for example, purple bacteria and blue-green algae). They do not have a nucleus, chromatophores, or vacuoles. There are nucleoproteins. Cyanobacteria break down water into hydrogen, used for the synthesis of carbohydrates, and oxygen. Capable of using nitrogen from the air and converting it into organic forms of nitrogen. During photosynthesis, oxygen is released. They have chlorophyll a and blue and brown pigments. They reproduce asexually. 5. Chemosynthesis - synthesis of organic compounds from carbon dioxide and water, carried out not due to the energy of light, but due to the energy of oxidation of inorganic substances. Chemosynthetic organisms include some types of bacteria. Nitrifying bacteria oxidize ammonia to nitrogen and then to nitric acid(NH3 → HNO2 → HNO3). Iron bacteria convert ferrous iron into oxide iron (Fe2+ → Fe3+). Sulfur bacteria oxidize hydrogen sulfide to sulfur or sulfuric acid (H2S + ½O2 → S + H2O, H2S + 2O2 → H2SO4). As a result of oxidation reactions of inorganic substances, energy is released, which is stored by bacteria in the form of high-energy ATP bonds. ATP is used for the synthesis of organic substances, which proceeds similarly to the reactions of the dark phase of photosynthesis. Chemosynthesizing bacteria contribute to the accumulation of minerals in the soil, improve soil fertility, and promote cleaning Wastewater and etc.

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Significance Participate in the cycle of substances in nature. Participate in the formation of soil structure and fertility. In the formation and destruction of mineral resources. Maintain carbon dioxide reserves in the atmosphere. Used in food, microbiological, chemical and other industries. Pathogenic – causative agents of disease. Microorganisms are used for biological wastewater treatment and soil quality improvement. Currently, methods have been developed for the production of manganese, copper, and chromium by developing waste dumps of old mines using bacteria, where conventional mining methods are not economically viable. Escherichia coli, a bacterium that lives in the human intestine, is used in genetic engineering. It is with its help that growth hormone is obtained - somatotropin, the hormone insulin, and the protein interferon, which helps cope with viral infection. The most important ecological functions of bacteria are nitrogen fixation and mineralization of organic remains. The binding of molecular nitrogen by bacteria to form ammonia (nitrogen fixation) and subsequent nitrification of ammonia is vital important process, because plants cannot absorb nitrogen gas. Approximately 90% of fixed nitrogen is produced by bacteria, mainly blue-green algae and rhizobium bacteria. Bacteria are widely used in Food Industry for the production of cheeses and fermented milk products, pickling cabbage (this produces organic acids). Bacteria are used for leaching of ores (primarily copper and uranium), for treating wastewater from organic residues, for processing silk and leather, for controlling agricultural pests, and for the production of medicines (for example, interferon). Some bacteria settle in the digestive tract of herbivores, ensuring the digestion of fiber. Bacteria bring not only benefits, but also harm. They breed in food products, thereby causing their damage. To stop reproduction, products are pasteurized (maintained for half an hour at a temperature of 61–63 °C), stored in the cold, dried (drying or smoking), salted or pickled. Bacteria cause serious diseases in humans (tuberculosis, anthrax, tonsillitis, food poisoning, gonorrhea, etc.), animals and plants (for example, fire blight of apple trees). Favorable external conditions increase the rate of bacterial growth and can cause epidemics. Pathogenic bacteria enter the body by airborne droplets, through wounds and mucous membranes, and the digestive tract. Symptoms of diseases caused by bacteria are usually explained by the action of poisons produced by these microorganisms or formed when they are destroyed.

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Scheme of implementation of genetic information in pro- and eukaryotes. In prokaryotes, protein synthesis by the ribosome (translation) is not spatially separated from transcription and can occur even before the completion of mRNA synthesis by RNA polymerase. Prokaryotic mRNAs are often polycistronic, meaning they contain several independent genes.