Prokaryotes and eukaryotes. Two types of cells are known in modern and fossil organisms: prokaryotic and eukaryotic. These cells differ so much in structural features that two superkingdoms have been distinguished - prokaryotes (pre-nuclear) 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 protein-bound DNA is organized into chromosomes, which are located in a special formation, in fact the largest cell organelle - the nucleus. In addition, the extranuclear active content of such a cell is divided into separate compartments with the help of the endoplasmic reticulum. EPS is formed by a simple membrane. Eukaryotic cells are usually larger than prokaryotic ones.
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"Mitosis Cell Division" - Prophase Metaphase Anaphase Telophase. Metaphase. Anaphase. Interphase. DNA coiling occurs in the nucleus; The nucleoli disappear. Spindle formation, chromosome shortening, formation of the equatorial plate. Then mitosis (cell division) occurs, and the cycle repeats itself. Mitosis disorders. Telophase.
"Cell of the body" - The prokaryotic type of cellular organization preceded the eukaryotic type of cellular organization. 1. Introduction. Hypothesis. What explains the diversity of cell types? 3 Comparison of plant and animal cells. Working group: Kobets V., Dedova A., Fokina A., Nechaev S., Tsvetkov V., Datskevich Yu.
"A cell in an organism" - The cells of most unicellular organisms contain all the parts of eukaryotic cells. Microscopes have been constantly improved. Classification of cells. Cells of multicellular animals. Somatic cells Sex cells. Test questions. What are the components of a cell? 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" - a thread. biological meaning. Types of cell division. Somatic. Anaphase. Metaphase. Amitosis. Telophase. early prophase. Sexual.
"Meiosis" - From the original cells with a diploid set of chromosomes, gametes with a haploid set arise. 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 of organisms is the process of cell division.
Lesson objectives: to study the specific features of plant, animal and fungal cells; identify common structures in their structure; to continue the formation of ideas about the two levels of cellular organization - prokaryotic and eukaryotic; to acquaint students with the features of the structure and vital activity of prokaryotic cells.
Matthias Jacob Schleiden (), German botanist, one of the creators of the theory of cell structure. Theodor Schwann (), German histologist and physiologist, one of the creators of the cell theory
Similarities in the structure of plant, animal and fungal cells All nuclear cells are covered with the thinnest membrane that protects the internal contents of the cells, connects them with each other and with the external environment. The most important organelle of all cells of plants, animals and fungi is the nucleus. It is usually located in the center of the cell and contains one or more nucleoli. In the nucleus there are special bodies of chromosomes that become visible only during nuclear division. They store hereditary information.
Similarities in the structure of plant, animal and fungal cells An obligatory part of the cells of plants, animals and fungi is a colorless semi-liquid cytoplasm. It fills the space between the membrane and the nucleus. In the cytoplasm, in addition to the nucleus, there are other organelles, as well as reserve nutrients. Conclusions: Common features in the structure of nuclear cells indicate the relationship and unity of their origin.
Cytoplasm membrane vacuole nucleus Golgi complex ribosomes plastids mitochondria 8 Place the numbers according to the indicated terms endoplasmic reticulum 9
Task: study the text of the textbook p. 2.7., make a table “Similarities and differences between prokaryotes and eukaryotes” Structure Eukaryotic cell Prokaryotic cell Cell wall Cell membrane Nucleus Chromosomes EPS Ribosomes Golgi complex Lysosomes Mitochondria Vacuoles Plastids
Features of the structure of prokaryotes -Prokaryotic cells have all the most important life functions, but they do not have membrane-encircled organelles found in eukaryotic cells. -The most important feature of prokaryotes is that they do not have a nucleus surrounded by a membrane. It is this feature that is decisive in the division of cells into prokaryotic and eukaryotic.
Homework: - Study § 2.7., notes in a notebook; - repeat; - prepare for the "Cell structure of organisms" test survey
"Structure and functions of the cell" - Nuclei of the cell. Shell. Microscope. Cell center. Kernel shell. Cell structure. Scientist. Cytoplasm. Lysosomes. Chromosomes. Nucleus. Mitochondria. Organoid. Cell types. How to see and study the cell. Ribosome. Golgi complex. Electron microscope. Nuclear juice. Cytoskeleton. Endoplasmic reticulum.
"The composition of a living cell" - The structure and nuclei of the cell. Lysosomes. Methods for studying cells. The history of the development of the doctrine of the cell. Golgi apparatus. Kernel functions. Ribosomes. Chromosomes. Plastids. Outer cytoplasmic membrane. Organelles of movement. Types of endoplasmic reticulum. Organelles are structures that are constantly present in the cell. Mitochondria. Endoplasmic reticulum of the EPS. eukaryotic cell. Cytoskeleton. Nuclear juice. Karyolemma.
"Non-membrane organelles" - Non-membrane organelles. The structure of the cell center. Diagram of the assembly of the ribosome. Cell center. Different types of euglena. Ultramicroscopic structure of the flagellum. Ribosomes. Structure of flagella and cilia. Organization of the cell center. Centrioles. Organelles of movement. The structure of the centriole.
"Structure of the cell of the body" - Cell nucleus. Mitochondria. Cell division. Importance of ATP in metabolism. Ribosome. Energy metabolism in the cell. Cell structure. Cell center. Nucleus. Endoplasmic reticulum. Golgi apparatus. Lysosome. Metabolism. Plastids. Cell theory. The value of cell organelles. Transformation of energy in the cell.
"Membrane" - Laboratory research. Consolidation. Structure. Differences. Membrane structure model. Membrane functions. charged molecules. Glycoprotein. Exocytosis. similarity. Compare prokaryotic cells with eukaryotic ones. eukaryotic cell. Plasmolysis in Elodea leaf. cell organelles. Macrophage work. Diffusion. Let's work in the lab. Microscopic structure of cells. Lesson terminology. Facilitated diffusion.
"The structure of eukaryotes and prokaryotes" - The meaning of bacteria. Cytoplasm. Habitat. Prokaryotes. Compare eukaryotic and prokaryotic cells. bacteria. The ability to actively move. Survival of prokaryotes. Heterotrophs. Discovery history. The number of bacteria. Cell structure. Organoid. Diverse ways of eating. The role of bacteria in nature. The simplicity of the structure. Mitochondria. genetic material. Differences in the structure of eukaryotic and prokaryotic cells.
Characteristics of bacteria Distributed everywhere: in water, soil, air, living organisms. They are found both in the deepest oceanic depressions and on the highest mountain peak of the Earth, Everest, both in the ice of the Arctic and Antarctica, and in hot springs. In the soil, they penetrate to a depth of 4 km or more, bacterial spores in the atmosphere are found at a height of up to 20 km, the hydrosphere has no boundaries at all for the habitat of these organisms. Bacteria are able to settle on almost any organic or inorganic substrate. Despite the simplicity of the structure, they have a high degree of adaptability to a wide variety of environmental conditions. This is possible due to the ability of bacteria to rapidly change generations. With a sharp change in the conditions of existence among bacteria, mutant forms quickly appear that can exist in new environmental conditions.
Sizes from 1 to 15 microns. According to the shape of the cells, they are distinguished: Spherical cocci: micrococci divide in different planes, lie singly; diplococci divide in one plane, form pairs; tetracocci divide in two planes, form tetrads; streptococci divide in one plane, form chains; staphylococci divide in different planes, form clusters resembling bunches of grapes; Sarcins are divided in three planes, forming packs of 8 individuals. Characterization of bacteria
Elongated bacilli (rod-shaped) are divided in different planes, lie singly; Convoluted - vibrios (in the form of a comma); spirilla have 4 to 6 turns; spirochetes are long and thin convoluted forms with the number of turns from 6 to 15. In addition to the main ones, other, very diverse, forms of bacterial cells are found in nature. Characterization of bacteria
Cell wall. The bacterial cell is enclosed in a dense, rigid cell wall, which accounts for 5 to 50% of the dry mass of the cell. The cell wall acts as an outer barrier of the cell, establishing contact between the microorganism and the environment. The main component of the bacterial cell wall is the polysaccharide murein. According to the content of murein, all bacteria are divided into two groups: gram-positive and gram-negative. Characterization of bacteria
In many bacteria, a mucilaginous matrix is located on top of the cell wall. Capsules are formed by polysaccharides. Sometimes the capsule contains polypeptides. As a rule, the capsule performs a protective function, protecting the cell from the action of adverse environmental factors. In addition, it can promote attachment to the substrate and participate in locomotion. Characterization of bacteria
The cytoplasmic membrane regulates the entry of nutrients into the cell and the exit of metabolic products to the outside. Usually, the growth rate of the cytoplasmic membrane outstrips the growth rate of the cell wall. This leads to the fact that the membrane often forms numerous invaginations (invaginations) of various forms of the mesosome. Characterization of bacteria
Nucleoid-bound mesosomes play a role in DNA replication and subsequent chromosome segregation. It is possible that mesosomes provide for the division of the cell into separate separate compartments, thereby creating favorable conditions for the enzymatic processes to occur. Characterization of bacteria
Bacterial cells can have a variety of cytoplasmic inclusions, gas bubbles, bubbles containing bacteriochlorophyll, polysaccharides, sulfur deposits, and others. Nucleoid. Bacteria do not have a structured nucleus. The genetic apparatus of bacteria is called the nucleoid. It is a DNA molecule concentrated in a limited space of the cytoplasm. Characterization of bacteria
The DNA molecule has a typical structure. It consists of two polynucleotide chains forming a double helix. Unlike eukaryotes, DNA has a circular structure, not a linear one. A bacterial DNA molecule is identified with one eukaryotic chromosome. But if in eukaryotes in the chromosomes DNA is associated with proteins, then in bacteria DNA does not form complexes with proteins. Bacterial DNA is anchored to the cytoplasmic membrane in the mesosome region. Characterization of bacteria
The cells of many bacteria have non-chromosomal plasmid genetic elements. They are small circular DNA molecules that can replicate independently of chromosomal DNA. Among them, the F-factor plasmid that controls the sexual process is distinguished. Flagella. Among bacteria there are many mobile forms. Flagella play the main role in locomotion. Bacterial flagella are only superficially similar to eukaryotic flagella, but their structure is different. They have a smaller diameter and are not surrounded by a cytoplasmic membrane. The flagellum filament consists of 3-11 helically twisted fibrils formed by the flagellin protein. Characterization of bacteria
At the base there is a hook and paired discs connecting the thread with the cytoplasmic membrane and cell wall. Flagella move by rotating in the membrane. The number and arrangement of flagella on the cell surface may vary. Fimbriae are thin, filamentous structures on the surface of bacterial cells, which are short, straight, hollow cylinders formed by the protein pilin. Thanks to pili, bacteria can attach to the substrate or interlock with each other. Special fimbriae sex fimbriae, or F-pili, provide for the exchange of genetic material between cells. Characterization of bacteria
When unfavorable conditions occur, endospores are formed in Gram-positive bacteria. In this case, the cell is dehydrated, the nucleoid is concentrated in the sporogenous zone. Protective shells are formed that protect bacterial spores from adverse conditions (the spores of many bacteria withstand heating up to 130 ° C and remain viable for decades). When favorable conditions occur, the spore germinates and a vegetative cell is formed. Characterization of bacteria
To summarize: What is known about the shape of bacteria? Cocci (diplococci, tetracocci, streptococci, sarcins, staphylococci), bacilli, vibrios, spirilla, spirochetes). What are the sizes of bacteria? 1 to 15 microns (µm). How is the bacterial cell wall structured? Plasmalemm and murein cell wall. Gram-negatives have two membranes. How is the genetic material of bacteria organized? Nucleoid - circular DNA and plasmids. What organelles are found in bacterial cells? Mesosomes, chlorosomes, 70-S ribosomes, flagella. How is a bacterial flagellum different from a eukaryotic flagellum? Not covered by a membrane, consists of several fibills of flagellin twisted together. Can bacteria reproduce by spores? No disputes - a way of experiencing adverse conditions.
Olympians! Spore-forming aerobic bacteria, in which the spore size does not exceed the diameter of the cell, are called bacilli. Spore-forming anaerobic bacteria, in which the spore size exceeds the cell diameter, and therefore they take the form of a spindle and are called clostridium (from Latin Clostridium - spindle). Characterization of bacteria
Olympians! Rickettsia are small, Gram-negative, rod-shaped bacteria up to 1 µm in size. Arthropods are their hosts and carriers. In humans, they cause typhus, tick-borne rickettsiosis, and Rocky Mountain spotted fever. Mycoplasmas are small bacteria that do not have a cell wall, surrounded only by a cytoplasmic membrane. Osmotically sensitive, in humans they cause a disease like a respiratory infection. Actinomycetes - (radiant fungi), occupy an intermediate position between bacteria and fungi. Branching Gram-positive bacteria. In the affected tissues, mycelium is formed from densely intertwined threads (hyphae) in the form of rays extending from the center and ending in flask-shaped thickenings. On aerial hyphae, spores can form, which serve for reproduction.
Another group, autotrophs, is able to synthesize organic substances from inorganic ones. Among them, there are: photoautotrophs, synthesizing organic substances due to the energy of light, and chemoautotrophs, synthesizing organic substances due to the chemical energy of the oxidation of inorganic substances: sulfur, hydrogen sulfide, ammonia, etc. These include nitrifying bacteria, iron bacteria, hydrogen bacteria, etc. Photoautotrophs: Photosynthetic sulfur bacteria (green and purple) They have photosystem-1 and do not emit oxygen during photosynthesis, the hydrogen donor is H 2 S: 6CO H 2 S C 6 H 12 O S + 6H 2 O Cyanobacteria (blue-green) have a photosystem-2 and during photosynthesis, oxygen is released, the hydrogen donor for the synthesis of organics is H 2 O: 6CO H 2 O C 6 H 12 O 6 + 6O 2 + 6H 2 O Bacterial Physiology
Chemoautotrophs: Chemoautotrophs use the energy of chemical bonds. Opened in 1887 by S.N. Vinogradsky. The most important group of chemoautotrophs is nitrifying bacteria capable of oxidizing ammonia formed during decay of organic residues, first to nitrous and then to nitric acid: 2NH 3 + 3O 2 = 2HNO 2 + 2H 2 O kJ 2HNO 2 + O 2 = 2HNO kJ oxidize hydrogen sulfide and accumulate sulfur in their cells: 2H 2 S + O 2 \u003d 2H 2 O + 2S kJ With a lack of hydrogen sulfide, bacteria further oxidize sulfur to sulfuric acid: 2S + 3O 2 + 2H 2 O \u003d 2H 2 SO kJ Iron bacteria oxidize divalent iron to trivalent: 4FeCO 3 + O 2 + H 2 O \u003d 4Fe (OH) 3 + 4CO kJ Hydrogen bacteria use the energy released during the oxidation of molecular hydrogen: 2H 2 + O 2 \u003d 2H 2 O kJ Physiology of bacteria
Reproduction of bacteria. Bacteria are capable of intensive reproduction. There is no sexual reproduction in bacteria, only asexual reproduction is known. Some bacteria, under favorable conditions, are able to divide every 20 minutes. Asexual Reproduction Asexual reproduction is the main mode of reproduction of bacteria. It can be carried out by binary fission and budding. Most bacteria reproduce by binary equal-sized transverse cell division. In this case, two identical daughter cells are formed. Before division, DNA replication occurs. Budding. Some bacteria reproduce by budding. At the same time, a short outgrowth of hyphae is formed at one of the poles of the mother cell, at the end of which a kidney is formed, one of the divided nucleoids passes into it. The kidney grows, turning into a daughter cell, and separates from the mother cell as a result of the formation of a septum between the kidney and the hyphae. Physiology of bacteria
Sexual process, or genetic recombination. There is no sexual reproduction, but the sexual process is known. Gametes are not formed in bacteria, there is no cell fusion, but the main event of the sexual process is the exchange of genetic information. This process is called genetic recombination. Part of the DNA (rarely all) by the donor cell transfers to the recipient cell and replaces part of the DNA of the recipient cell. The resulting DNA is called recombinant. It contains the genes of both parent cells. Physiology of bacteria
There are three ways of genetic recombination: conjugation, transduction, transformation; Conjugation is the direct transfer of a piece of DNA from one cell to another during direct contact between cells. The donor cell forms what is called an F-pill, its formation is controlled by a special plasmid, the F-plasmid. During conjugation, DNA is transmitted only in one direction (from donor to recipient), there is no reverse transmission. Physiology of bacteria
Participation in the cycle of chemical elements (nitrogen, carbon, oxygen, etc.). Groups of bacteria involved in the nitrogen cycle Nitrogen-fixing bacteria Use of free nitrogen to form compounds available to other organisms Enrichment of soil with nitrogen compounds Ammonifying bacteria Decomposition of nitrogen-containing substances (proteins, nucleic acids) with the formation of ammonia Mineralization Nitrifying bacteria Oxidation of ammonia salts to nitrites, then to nitrates Mineralization Denitrifying bacteria Reduction of nitrites and nitrates to free nitrogen Mineralization Significance of bacteria Destruction of organic residues. Participation in soil formation. Participation in the formation of the atmosphere. Use in the food industry for the production of lactic acid products Obtaining antibiotics, amino acids, vitamins, etc. Wastewater treatment, methane formation Symbionts of many organisms (E. coli in humans) Cause infectious diseases (tuberculosis, tonsillitis) Currently, using transformed E. coli , receive insulin, somatotropic hormone, interferon The value of bacteria
Significance of bacteria Steps: Restriction (cutting human DNA and plasmids with restrictases) Creation of a vector containing all control genes (regulator, operator, marker genes) Ligation (“sewing” of a human DNA fragment into plasmids with ligases) Transformation (introduction of recombinant plasmids into bacterial cells) Screening (selection of such transformed bacteria that carry the gene necessary for humans) Reproduction of precisely those transformed bacteria that carry the gene necessary for humans.
"Study of the cell" - Table 2. Calculation of the magnification of the microscope. Onion skin cells under a microscope. Types of cells. Epigraph of the lesson. Conclusions. Micropreparation. Lesson plan. The main parts of the cell. Table 1. Parts of the microscope. The history of the discovery of the cell. The main parts of the cell are: membrane, cytoplasm and nucleus. All living things have a cellular structure.
"Mitosis and meiosis" - Vegetative reproduction. Types of reproduction. Cell cytokinesis (photo). Lumps of chromatin in the interphase nucleus. In anaphase 2, chromatids diverge to the poles, which become daughter chromosomes. The spindle fibers are attached to two chromatid chromosomes. Mitosis = division of the nucleus + division of the cytoplasm. Reproduction is the reproduction of their own kind, ensuring the continuity and continuity of life.
"Meiosis lesson" - Meiosis. Chromosomal sex determination. Nitrogen cycle in the biosphere. hereditary diseases. Cycle of carbon in the biosphere. plastic exchange. Metabolism. Cycle of phosphorus in the biosphere. Comparison of mitosis and meiosis. Reference notes used in the lessons.
"Energy exchange" - Reactions. (Glycolysis). Movie. Solve the problem. Learning new material Consolidation. Fermentation. 1 2. Enzymatic and oxygen-free process of decomposition 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 of Meiosis" - Mitosis. Meiosis. Improving the visual perception of the material; Formation of search skills; Tasks: Cell division. Mitosis and meiosis. Purpose: Biology Grade 9.
"The structure of the cell and its functions" - Exocytosis. Scheme of the structure of hereditary information. The number of mitochondria in one cell varies from a few to several thousand. Mandatory part of the cell, enclosed between the plasma membrane and the nucleus. Cell center. Chromoplasts. Movement organelles. Mitochondria is a universal organelle that is a respiratory and energy center.
