Structural levels of organization of living matter presentation. Features of the biological level of organization of matter

Slide 7

After the defeat of the fascist German troops in the Battle of Stalingrad, the fascist German command, planning the summer campaign of 1943, decided to conduct a major offensive on the Soviet-German front in order to regain the lost strategic initiative. It was planned to deliver converging attacks from the areas of the cities of Orel (from the north) and Belgorod (from the south). The strike groups were supposed to unite in the Kursk area, encircling the Red Army troops. The operation was called "Citadel". The Germans concentrated up to 50 divisions (16 tank and motorized) 2 tank brigades, about 900 thousand people.

Slide 8

The Soviet command decided to conduct a defensive battle, exhaust the enemy troops and defeat them. For this purpose, a deeply layered defense was created on both sides of the Kursk bulge. About 8 defensive lines were created. The troops of the Central and Voronezh fronts numbered: More than 1 million 300 thousand people Up to 20 thousand guns and mortars About 3600 tanks About 2950 aircraft

Slide 9

Kursk defensive operation.

The German offensive began on July 5, 1943. But since the Soviet command knew the start time of the operation, artillery and air counter-preparation was carried out in 30-40 minutes. The Germans were still sleeping, but Soviet counter-preparations woke them up. It was late, but the offensive still began. The enemy sought to break through to Kursk from the north and south and encircle the troops of the Voronezh and Central Fronts. Having stumbled upon a previously prepared defense, the German tank divisions suffered significant losses, but were unable to break through it.

Slide 10

The German offensive ended on July 12 with a tank battle near the village of Prokhorovka - the largest counter tank battle in World War II. 1,200 tanks took part in it on both sides. The Prokhorovsky field entered the annals of Russian military history along with the Kulikovo and Borodino fields.

Slide 11

Oryol and Belgorod-Kharkov operation.

After the failure of the attack on Kursk, the Germans went on the defensive, but were unable to hold their position. The counteroffensive of the Soviet troops ended in complete victory. At the second stage of the battle, Soviet troops defeated the main enemy groups. On August 5, Belgorod and Orel were liberated. In honor of this victory, the first artillery salute during the Great Patriotic War was fired in Moscow. On August 23, Kharkov, the most important political, economic and strategic center of the south of the country, was liberated. The Battle of Kursk ended with the liberation of Kharkov.

Federal Agency for Health and Social Affairs

Biology test

Qualitative features of living matter. Levels of organization of living things.

Chemical composition of the cell (proteins, their structure and functions)

Completed by a student

1st year 195 group

correspondence department

Faculty of Pharmacy

Chelyabinsk 2009

Qualitative features of living matter. Levels of organization of living things

Any living system, no matter how complex it is organized, consists of biological macromolecules: nucleic acids, proteins, polysaccharides, as well as other important organic substances. From this level, various vital processes of the body begin: metabolism and energy conversion, transmission of hereditary information, etc.

The cells of multicellular organisms form tissues - systems of cells similar in structure and function and intercellular substances associated with them. Tissues are integrated into larger functional units called organs. Internal organs are characteristic of animals; here they are part of organ systems (respiratory, nervous, etc.). For example, the digestive system: oral cavity, pharynx, esophagus, stomach, duodenum, small intestine, colon, anus. Such specialization, on the one hand, improves the functioning of the body as a whole, and on the other, requires an increased degree of coordination and integration of various tissues and organs.

The cell is a structural and functional unit, as well as a unit of development of all living organisms living on Earth. At the cellular level, the transfer of information and the transformation of substances and energy are coupled.

The elementary unit of the organismal level is the individual, which is considered in development - from the moment of origin to the end of existence - as a living system. Organ systems emerge that are specialized to perform various functions.

A set of organisms of the same species, united by a common habitat, in which a population is created - a supraorganismal system. In this system, elementary evolutionary transformations are carried out.

Biogeocenosis is a collection of organisms of different species and varying complexity of organization with environmental factors. In the process of joint historical development of organisms of different systematic groups, dynamic, stable communities are formed.

The biosphere is the totality of all biogeocenoses, a system that covers all phenomena of life on our planet. At this level, the circulation of substances and the transformation of energy associated with the vital activity of all living organisms occurs.

Table 1. Levels of organization of living matter

Molecular

The initial level of organization of living things. The subject of research is molecules of nucleic acids, proteins, carbohydrates, lipids and other biological molecules, i.e. molecules found in the cell. Any living system, no matter how complex it is organized, consists of biological macromolecules: nucleic acids, proteins, polysaccharides, as well as other important organic substances. From this level, various vital processes of the body begin: metabolism and energy conversion, transmission of hereditary information, etc.

Cellular

The study of cells that act as independent organisms (bacteria, protozoa and some other organisms) and cells that make up multicellular organisms.

Fabric

Cells that have a common origin and perform similar functions form tissues. There are several types of animal and plant tissues with different properties.

Organ

In organisms, starting with the coelenterates, organs (organ systems) are formed, often from tissues of various types.

Organismal

This level is represented by unicellular and multicellular organisms.

Population-species

Organisms of the same species living together in certain areas constitute a population. Now on Earth there are about 500 thousand species of plants and about 1.5 million species of animals.

Biogeocenotic

It is represented by a collection of organisms of different species, depending on each other to one degree or another.

Biosphere

The highest form of organization of living things. Includes all biogeocenoses associated with general metabolism and energy conversion.

Each of these levels is quite specific, has its own patterns, its own research methods. It is even possible to single out sciences that conduct their research at a certain level of organization of living things. For example, at the molecular level living things are studied by such sciences as molecular biology, bioorganic chemistry, biological thermodynamics, molecular genetics, etc. Although the levels of organization of living things are distinguished, they are closely interconnected and flow from one another, which speaks of the integrity of living nature.

Cell membrane. Surface apparatus of the cell, its main parts, their purpose

A living cell is a fundamental particle of the structure of living matter. It is the simplest system that has the full range of properties of living things, including the ability to transfer genetic information. The cell theory was created by German scientists Theodor Schwann and Matthias Schleiden. Its main position is the statement that all plant and animal organisms consist of cells that are similar in structure. Research in the field of cytology has shown that all cells carry out metabolism, are capable of self-regulation and can transmit hereditary information. The life cycle of any cell ends either by division and continuation of life in a renewed form, or by death. At the same time, it turned out that cells are very diverse; they can exist as unicellular organisms or as part of multicellular ones. The lifespan of cells may not exceed several days, or may coincide with the lifespan of the organism. Cell sizes vary greatly: from 0.001 to 10 cm. Cells form tissues, several types of tissues - organs, groups of organs associated with solving some common problems are called body systems. Cells have a complex structure. It is separated from the external environment by a shell, which, being loose and loose, ensures the interaction of the cell with the outside world, the exchange of matter, energy and information with it. Cell metabolism serves as the basis for another of their most important properties - maintaining stability and stability of the conditions of the internal environment of the cell. This property of cells, inherent in the entire living system, is called homeostasis. Homeostasis, that is, the constancy of the composition of the cell, is maintained by metabolism, that is, metabolism. Metabolism is a complex, multi-stage process, including the delivery of raw materials into the cell, the production of energy and proteins from them, and the removal of produced useful products, energy and waste from the cell into the environment.

The cell membrane is the cell membrane that performs the following functions:

separation of cell contents and external environment;

regulation of metabolism between the cell and the environment;

the site of some biochemical reactions (including photosynthesis, oxidative phosphorylation);

association of cells into tissues.

The membranes are divided into plasmatic (cell membranes) and external. The most important property of the plasma membrane is semi-permeability, that is, the ability to allow only certain substances to pass through. Glucose, amino acids, fatty acids and ions slowly diffuse through it, and the membranes themselves can actively regulate the diffusion process.

According to modern data, plasma membranes are lipoprotein structures. Lipids spontaneously form a bilayer, and membrane proteins “float” in it. Membranes contain several thousand different proteins: structural, transporters, enzymes and others. It is assumed that there are pores between protein molecules through which hydrophilic substances can pass (the lipid bilayer prevents their direct penetration into the cell). Some molecules on the membrane surface have glycosyl groups attached to them, which are involved in the process of cell recognition during tissue formation.

Different types of membranes differ in their thickness (usually it ranges from 5 to 10 nm). The consistency of the lipid bilayer resembles olive oil. Depending on external conditions (cholesterol is the regulator), the structure of the bilayer can change so that it becomes more liquid (membrane activity depends on this).

An important problem is the transport of substances across plasma membranes. It is necessary for the delivery of nutrients into the cell, the removal of toxic waste, and the creation of gradients to maintain nervous and muscle activity. The following mechanisms exist for the transport of substances across the membrane:

diffusion (gases, fat-soluble molecules penetrate directly through the plasma membrane); with facilitated diffusion, a water-soluble substance passes through the membrane through a special channel created by a specific molecule;

osmosis (diffusion of water through semi-permeable membranes);

active transport (transfer of molecules from an area of ​​lower concentration to an area of ​​higher concentration, for example, through special transport proteins, requires ATP energy);

during endocytosis, the membrane forms invaginations, which are then transformed into vesicles or vacuoles. There are phagocytosis - the absorption of solid particles (for example, by blood leukocytes) - and pinocytosis - the absorption of liquids;

exocytosis is the reverse process of endocytosis; Undigested remains of solid particles and liquid secretions are removed from the cells.

Supramembrane structures may be located above the plasma membrane of the cell. Their structure is a wet classification feature. In animals this is the glycocalyx (protein-carbohydrate complex), in plants, fungi and bacteria it is the cell wall. The cell wall of plants includes cellulose, fungi - chitin, bacteria - the protein-polysaccharide complex murein.

The basis of the cell surface apparatus (SAC) is the outer cell membrane, or plasmalemma. In addition to the plasma membrane, the PAA has a supra-membrane complex, and in eukaryotes there is also a sub-membrane complex.

The main biochemical components of plasmalemma (from the Greek plasma - formation and lemma - shell, crust) are lipids and proteins. Their quantitative ratio in most eukaryotes is 1: 1, and in prokaryotes proteins predominate in the plasmalemma. A small amount of carbohydrates is found in the outer cell membrane and fat-like compounds can be found (in mammals - cholesterol, fat-soluble vitamins).

The supramembrane complex of the cell surface apparatus is characterized by a variety of structures. In prokaryotes, the supramembrane complex in most cases is represented by a cell wall of varying thickness, the basis of which is the complex glycoprotein murein (in archaebacteria - pseudomurein). In a number of eubacteria, the outer part of the supramembrane complex consists of another membrane with a high content of lipopolysaccharides. In eukaryotes, the universal component of the supramembrane complex is carbohydrates - components of glycolipids and glycoproteins of the plasmalemma. Due to this, it was originally called glycocalyx (from the Greek glycos - sweet, carbohydrate and Lat. callum - thick skin, shell). In addition to carbohydrates, the glycocalyx includes peripheral proteins above the bilipid layer. More complex variants of the supramembrane complex are found in plants (cell wall made of cellulose), fungi and arthropods (external covering made of chitin).

The submembrane (from the Latin sub - under) complex is characteristic only of eukaryotic cells. It consists of a variety of protein thread-like structures: thin fibrils (from the Latin fibrilla - fiber, thread), microfibrils (from the Greek micros - small), skeletal (from the Greek skeleton - dried) fibrils and microtubules. They are connected to each other by proteins and form the musculoskeletal apparatus of the cell. The submembrane complex interacts with plasmalemma proteins, which, in turn, are associated with the supramembrane complex. As a result, the PAK is a structurally integral system. This allows it to perform important functions for the cell: insulating, transport, catalytic, receptor-signaling and contact.

Chemical composition of the cell (proteins, their structure and functions)

Chemical processes occurring in a cell are one of the main conditions for its life, development, and functioning.

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All cells of plant and animal organisms, as well as microorganisms, are similar in chemical composition, which indicates the unity of the organic world.

Of the 109 elements of Mendeleev's periodic table, a significant majority were found in cells. Some elements are contained in cells in relatively large quantities, others in small quantities (Table 2).

Table 2. Content of chemical elements in the cell

Elements

Quantity (in%)

Elements

Quantity (in%)

Oxygen

In the first place among the substances of the cell is water. It makes up almost 80% of the cell mass. Water is the most important component of the cell, not only in quantity. It plays a significant and diverse role in the life of the cell.

Water determines the physical properties of the cell - its volume, elasticity. Water is of great importance in the formation of the structure of molecules of organic substances, in particular the structure of proteins, which is necessary to perform their functions. The importance of water as a solvent is great: many substances enter the cell from the external environment in an aqueous solution, and in an aqueous solution, waste products are removed from the cell. Finally, water is a direct participant in many chemical reactions (the breakdown of proteins, carbohydrates, fats, etc.).

The biological role of water is determined by the peculiarities of its molecular structure and the polarity of its molecules.

In addition to water, the inorganic substances of the cell also include salts. For vital processes, the most important cations included in the salts are K+, Na+, Ca2+, Mg2+, and the most important anions are HPO4-, H2PO4-, Cl-, HCO3-.

The concentration of cations and anions in the cell and in its habitat, as a rule, is sharply different. While the cell is alive, the ratio of ions inside and outside the cell is firmly maintained. After cell death, the ion content in the cell and in the environment quickly equalizes. The ions contained in the cell are of great importance for the normal functioning of the cell, as well as for maintaining a constant reaction within the cell. Despite the fact that acids and alkalis are continuously formed in the process of life, the normal reaction of the cell is slightly alkaline, almost neutral.

Inorganic substances are contained in the cell not only in a dissolved state, but also in a solid state. In particular, the strength and hardness of bone tissue is provided by calcium phosphate, and mollusk shells by calcium carbonate.

Organic substances form about 20 - 30% of the cell composition.

Biopolymers include carbohydrates and proteins. Carbohydrates contain carbon, oxygen, and hydrogen atoms. There are simple and complex carbohydrates. Simple - monosaccharides. Complex - polymers whose monomers are monosaccharides (oligosaccharides and polysaccharides). As the number of monomer units increases, the solubility of polysaccharides decreases and the sweet taste disappears.

Monosaccharides are solid, colorless crystalline substances that are highly soluble in water and very poorly (or not at all) soluble in organic solvents. Monosaccharides include trioses, tetroses, pentoses and hexoses. Among the oligosaccharides, the most common are disaccharides (maltose, lactose, sucrose). Polysaccharides are most often found in nature (cellulose, starch, chitin, glycogen). Their monomers are glucose molecules. They partially dissolve in water, swelling to form colloidal solutions.

Lipids are water-insoluble fats and fat-like substances consisting of glycerol and high molecular weight fatty acids. Fats are esters of trihydric alcohol glycerol and higher fatty acids. Animal fats are found in milk, meat, and subcutaneous tissue. In plants - in seeds and fruits. In addition to fats, cells also contain their derivatives - steroids (cholesterol, hormones and fat-soluble vitamins A, D, K, E, F).

Lipids are:

structural elements of cell membranes and cellular organelles;

energy material (1g of fat, when oxidized, releases 39 kJ of energy);

spare substances;

perform a protective function (in marine and polar animals);

affect the functioning of the nervous system;

a source of water for the body (1 kg, when oxidized, gives 1.1 kg of water).

Nucleic acids. The name “nucleic acids” comes from the Latin word “nucleus”, i.e. nucleus: They were first discovered in cell nuclei. The biological significance of nucleic acids is very great. They play a central role in storing and transmitting the hereditary properties of the cell, which is why they are often called substances of heredity. Nucleic acids ensure the synthesis of proteins in the cell, exactly the same as in the mother cell and the transmission of hereditary information. There are two types of nucleic acids - deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

The DNA molecule consists of two helically twisted strands. DNA is a polymer whose monomers are nucleotides. Nucleotides are compounds consisting of a molecule of phosphoric acid, the carbohydrate deoxyribose and a nitrogenous base. DNA has four types of nitrogenous bases: adenine (A), guanine (G), cytosine (C), thymine (T). Each DNA strand is a polynucleotide consisting of several tens of thousands of nucleotides. DNA doubling - reduplication - ensures the transfer of hereditary information from the mother cell to the daughter cells.

RNA is a polymer similar in structure to one strand of DNA, but smaller in size. RNA monomers are nucleotides consisting of phosphoric acid, the carbohydrate ribose and a nitrogenous base. Instead of thymine, RNA contains uracil. Three types of RNA are known: messenger RNA (i-RNA) - transmits information about the structure of a protein from a DNA molecule; transport (t-RNA) - transports amino acids to the site of protein synthesis; ribosomal (r-RNA) - found in ribosomes, involved in maintaining the structure of the ribosome.

A very important role in the bioenergetics of the cell is played by the adenyl nucleotide, to which two phosphoric acid residues are attached. This substance is called adenosine triphosphoric acid (ATP). ATP is a universal biological energy accumulator: the light energy of the sun and the energy contained in the food consumed is stored in ATP molecules. ATP is an unstable structure; when ATP transforms into ADP (adenosine diphosphate), 40 kJ of energy is released. ATP is produced in the mitochondria of animal cells and during photosynthesis in plant chloroplasts. ATP energy is used to perform chemical (synthesis of proteins, fats, carbohydrates, nucleic acids), mechanical (movement, muscle work) work, transformation into electrical or light (discharges of electric stingrays, eels, insect glow) energy.

Proteins are non-periodic polymers whose monomers are amino acids. All proteins contain atoms of carbon, hydrogen, oxygen, and nitrogen. Many proteins also contain sulfur atoms. There are proteins that also contain metal atoms - iron, zinc, copper. The presence of acidic and basic groups determines the high reactivity of amino acids. From the amino group of one amino acid and the carboxyl of another, a water molecule is released, and the released electrons form a peptide bond: CO-NN (it was discovered in 1888 by Professor A.Ya. Danilevsky), which is why proteins are called polypeptides. Protein molecules are macromolecules. There are many amino acids known. But only 20 amino acids are known as monomers of any natural proteins - animal, plant, microbial, viral. They were called "magic". The fact that the proteins of all organisms are built from the same amino acids is another proof of the unity of the living world on Earth.

There are 4 levels of organization in the structure of protein molecules:

1. Primary structure - a polypeptide chain of amino acids linked in a certain sequence by covalent peptide bonds.

2. Secondary structure - a polypeptide chain in the form of a helix. Numerous hydrogen bonds occur between the peptide bonds of adjacent turns and other atoms, providing a strong structure.

3. Tertiary structure - a configuration specific to each protein - a globule. It is held by low-strength hydrophobic bonds or cohesive forces between non-polar radicals, which are found in many amino acids. There are also covalent S-S bonds that occur between distantly spaced radicals of the sulfur-containing amino acid cysteine.

4. Quaternary structure occurs when several macromolecules combine to form aggregates. Thus, hemoglobin in human blood is an aggregate of four macromolecules.

Violation of the natural structure of a protein is called denaturation. It occurs under the influence of high temperature, chemicals, radiant energy and other factors.

The role of protein in the life of cells and organisms:

construction (structural) - proteins - the building material of the body (shells, membranes, organelles, tissues, organs);

catalytic function - enzymes that accelerate reactions hundreds of millions of times;

musculoskeletal function - proteins that make up skeletal bones and tendons; movement of flagellates, ciliates, muscle contraction;

transport function - blood hemoglobin;

protective - blood antibodies neutralize foreign substances;

energy function - when protein is broken down, 1 g releases 17.6 kJ of energy;

regulatory and hormonal - proteins are part of many hormones and take part in the regulation of the body’s life processes;

receptor - proteins carry out the process of selective recognition of individual substances and their attachment to molecules.

Metabolism in the cell. Photosynthesis. Chemosynthesis

A prerequisite for the existence of any organism is a constant flow of nutrients and the constant release of the end products of chemical reactions occurring in cells. Nutrients are used by organisms as a source of atoms of chemical elements (primarily carbon atoms), from which all structures are built or renewed. In addition to nutrients, the body also receives water, oxygen, and mineral salts.

Organic substances entering cells (or synthesized during photosynthesis) are broken down into building blocks - monomers and sent to all cells of the body. Some of the molecules of these substances are spent on the synthesis of specific organic substances inherent in a given organism. Cells synthesize proteins, lipids, carbohydrates, nucleic acids and other substances that perform various functions (construction, catalytic, regulatory, protective, etc.).

Another part of the low-molecular organic compounds that enter the cells goes to the formation of ATP, the molecules of which contain energy intended directly for performing work. Energy is necessary for the synthesis of all specific substances of the body, maintaining its highly ordered organization, active transport of substances within cells, from one cell to another, from one part of the body to another, for the transmission of nerve impulses, the movement of organisms, maintaining a constant body temperature (in birds and mammals ) and for other purposes.

During the transformation of substances in cells, end products of metabolism are formed that can be toxic to the body and are removed from it (for example, ammonia). Thus, all living organisms constantly consume certain substances from the environment, transform them and release final products into the environment.

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The set of chemical reactions occurring in the body is called metabolism or metabolism. Depending on the general direction of the processes, catabolism and anabolism are distinguished.

Catabolism (dissimilation) is a set of reactions leading to the formation of simple compounds from more complex ones. Catabolic reactions include, for example, reactions of hydrolysis of polymers to monomers and the breakdown of the latter to carbon dioxide, water, ammonia, i.e. energy metabolism reactions, during which the oxidation of organic substances and the synthesis of ATP occurs.

Anabolism (assimilation) is a set of reactions for the synthesis of complex organic substances from simpler ones. This includes, for example, nitrogen fixation and protein biosynthesis, the synthesis of carbohydrates from carbon dioxide and water during photosynthesis, the synthesis of polysaccharides, lipids, nucleotides, DNA, RNA and other substances.

The synthesis of substances in the cells of living organisms is often referred to as plastic metabolism, and the breakdown of substances and their oxidation, accompanied by the synthesis of ATP, as energy metabolism. Both types of metabolism form the basis of the life activity of any cell, and therefore any organism, and are closely related to each other. On the one hand, all plastic exchange reactions require the expenditure of energy. On the other hand, to carry out energy metabolism reactions, constant synthesis of enzymes is necessary, since their life expectancy is short. In addition, substances used for respiration are formed during plastic metabolism (for example, during the process of photosynthesis).

Photosynthesis is the process of formation of organic matter from carbon dioxide and water in the light with the participation of photosynthetic pigments (chlorophyll in plants, bacteriochlorophyll and bacteriorhodopsin in bacteria). In modern plant physiology, photosynthesis is more often understood as a photoautotrophic function - a set of processes of absorption, transformation and use of the energy of light quanta in various endergonic reactions, including the conversion of carbon dioxide into organic substances.

Photosynthesis is the main source of biological energy; photosynthetic autotrophs use it to synthesize organic substances from inorganic ones; heterotrophs exist at the expense of the energy stored by autotrophs in the form of chemical bonds, releasing it in the processes of respiration and fermentation. The energy obtained by humanity by burning fossil fuels (coal, oil, natural gas, peat) is also stored in the process of photosynthesis.

Photosynthesis is the main input of inorganic carbon into the biological cycle. All free oxygen in the atmosphere is of biogenic origin and is a by-product of photosynthesis. The formation of an oxidizing atmosphere (oxygen catastrophe) completely changed the state of the earth's surface, made the appearance of respiration possible, and later, after the formation of the ozone layer, allowed life to reach land.

Chemosynthesis is a method of autotrophic nutrition in which the source of energy for the synthesis of organic substances from CO2 is the oxidation reactions of inorganic compounds. This type of energy production is used only by bacteria. The phenomenon of chemosynthesis was discovered in 1887 by the Russian scientist S.N. Vinogradsky.

It should be noted that the energy released in the oxidation reactions of inorganic compounds cannot be directly used in assimilation processes. First, this energy is converted into the energy of macroenergetic bonds of ATP and only then is spent on the synthesis of organic compounds.

Chemolithoautotrophic organisms:

Iron bacteria (Geobacter, Gallionella) oxidize divalent iron to ferric iron.

Sulfur bacteria (Desulfuromonas, Desulfobacter, Beggiatoa) oxidize hydrogen sulfide to molecular sulfur or to sulfuric acid salts.

Nitrifying bacteria (Nitrobacteraceae, Nitrosomonas, Nitrosococcus) oxidize ammonia, formed during the decay of organic matter, to nitrous and nitric acids, which, interacting with soil minerals, form nitrites and nitrates.

Thionic bacteria (Thiobacillus, Acidithiobacillus) are capable of oxidizing thiosulfates, sulfites, sulfides and molecular sulfur to sulfuric acid (often with a significant decrease in the pH of the solution), the oxidation process differs from that of sulfur bacteria (in particular, in that thionic bacteria do not deposit intracellular sulfur). Some representatives of thionic bacteria are extreme acidophiles (able to survive and reproduce when the pH of the solution drops down to 2), capable of withstanding high concentrations of heavy metals and oxidizing metallic and ferrous iron (Acidithiobacillus ferrooxidans) and leaching heavy metals from ores.

Hydrogen bacteria (Hydrogenophilus) are capable of oxidizing molecular hydrogen and are moderate thermophiles (grow at a temperature of 50 °C)

Chemosynthetic organisms (for example, sulfur bacteria) can live in the oceans at great depths, in places where hydrogen sulfide comes out of fractures in the earth’s crust into the water. Of course, light quanta cannot penetrate water to a depth of about 3-4 kilometers (at this depth most ocean rift zones are located). Thus, chemosynthetics are the only organisms on earth that do not depend on the energy of sunlight.

On the other hand, ammonia, which is used by nitrifying bacteria, is released into the soil when plant or animal matter rots. In this case, the vital activity of chemosynthetics indirectly depends on sunlight, since ammonia is formed during the decomposition of organic compounds obtained from solar energy.

The role of chemosynthetics for all living beings is very great, since they are an indispensable link in the natural cycle of the most important elements: sulfur, nitrogen, iron, etc. Chemosynthetics are also important as natural consumers of such toxic substances as ammonia and hydrogen sulfide. Nitrifying bacteria are of great importance, they enrich the soil with nitrites and nitrates - it is mainly in the form of nitrates that plants absorb nitrogen. Some chemosynthetics (in particular, sulfur bacteria) are used for wastewater treatment.

According to modern estimates, the biomass of the “underground biosphere,” which is located, in particular, under the seabed and includes chemosynthetic anaerobic methane-oxidizing archaebacteria, may exceed the biomass of the rest of the biosphere.

Meiosis. Features of the first and second divisions of meiosis. Biological significance. The difference between meiosis and mitosis

Understanding of the fact that germ cells are haploid and therefore must be formed using a special mechanism of cell division came as a result of observations, which also almost for the first time suggested that chromosomes contain genetic information. In 1883, it was discovered that the nuclei of the egg and sperm of a certain type of worm contain only two chromosomes, while the fertilized egg already has four. The chromosomal theory of heredity could thus explain the long-standing paradox that the roles of the father and mother in determining the characteristics of the offspring often seem to be the same, despite the huge difference in the sizes of the egg and sperm.

Another important implication of this discovery was that sex cells must be formed as a result of a special type of nuclear division, in which the entire set of chromosomes is divided exactly in half. This type of division is called meiosis (a word of Greek origin meaning “reduction.” The name of another type of cell division, mitosis, comes from the Greek word meaning “thread”; this choice of name is based on the thread-like appearance of the chromosomes as they condense during nuclear division - this process occurs during both mitosis and meiosis) The behavior of chromosomes during meiosis, when their number is reduced, turned out to be more complex than previously thought. Therefore, the most important features of meiotic division were established only by the beginning of the 30s as a result of a huge number of thorough studies that combined cytology and genetics.

At the first meiotic division, each daughter cell inherits two copies of one of the two homologues and therefore contains a diploid amount of DNA.

The formation of haploid gamete nuclei occurs as a result of the second division of meiosis, in which the chromosomes line up at the equator of the new spindle and without further DNA replication, sister chromatids are separated from each other, as in normal mitosis, forming cells with a haploid DNA set.

Thus, meiosis consists of two cell divisions following a single phase of chromosome duplication, so that each cell that enters meiosis results in four haploid cells.

Sometimes the process of meiosis proceeds abnormally, and homologs cannot separate from each other - this phenomenon is called chromosome nondisjunction. Some of the haploid cells formed in this case receive an insufficient number of chromosomes, while others acquire their extra copies. From such gametes, defective embryos are formed, most of which die.

In the prophase of the first division of meiosis, during conjugation (synapsis) and separation of chromosomes, complex morphological changes occur in them. In accordance with these changes, prophase is divided into five successive stages:

leptotene;

zygotene;

pachytene;

diplotene;

diakinesis.

The most striking phenomenon is the initiation of close approximation of chromosomes in zygotene, when a specialized structure called the synaptonemal complex begins to form between pairs of sister chromatids in each bivalent. The moment of complete conjugation of chromosomes is considered the beginning of pachytene, which usually lasts several days; after the separation of chromosomes, the diplotene stage begins, when chiasmata become visible for the first time.

After the end of the long prophase I, two nuclear divisions without a separating period of DNA synthesis bring the process of meiosis to the end. These stages usually take up no more than 10% of the total time required for meiosis, and they have the same names as the corresponding stages of mitosis. The remainder of the first division of meiosis is divided into metaphase I, anaphase I and telophase I. By the end of the first division, the chromosome set is reduced, turning from tetraploid to diploid, just like in mitosis, and two cells are formed from one cell. The decisive difference is that during the first division of meiosis, each cell receives two sister chromatids connected at the centromere, and during mitosis, two separated chromatids enter.

Further, after a short interphase II, in which chromosomes do not double, the second division quickly occurs - prophase II, anaphase II and telophase II. As a result, from each diploid cell that has entered meiosis, four haploid nuclei are formed.

Meiosis consists of two successive cell divisions, the first of which lasts almost as long as the entire meiosis, and is much more complex than the second.

After the end of the first meiotic division, membranes are formed again in the two daughter cells and a short interphase begins. At this time, the chromosomes are somewhat despiralized, but soon they condense again and prophase II begins. Since no DNA synthesis occurs during this period, it appears that in some organisms the chromosomes pass directly from one division to the next. Prophase II in all organisms is short: the nuclear envelope is destroyed when a new spindle is formed, after which, in rapid succession, metaphase II, anaphase II and telophase II follow. As in mitosis, kinetochore filaments are formed in sister chromatids, extending from the centromere in opposite directions. At the metaphase plate, the two sister chromatids are held together until anaphase, when they separate due to the sudden separation of their kinetochores. Thus, the second division of meiosis is similar to normal mitosis, the only significant difference is that there is one copy of each chromosome, and not two, as in mitosis.

Meiosis ends with the formation of nuclear envelopes around the four haploid nuclei formed in telophase II.

In general, meiosis produces four haploid cells from one diploid cell. During gametic meiosis, gametes are formed from the resulting haploid cells. This type of meiosis is characteristic of animals. Gametic meiosis is closely related to gametogenesis and fertilization. During zygotic and spore meiosis, the resulting haploid cells give rise to spores or zoospores. These types of meiosis are characteristic of lower eukaryotes, fungi and plants. Spore meiosis is closely related to sporogenesis. Thus, meiosis is the cytological basis of sexual and asexual (spore) reproduction.

The biological significance of meiosis is to maintain a constant number of chromosomes in the presence of the sexual process. In addition, as a result of crossing over, recombination occurs - the appearance of new combinations of hereditary inclinations in chromosomes. Meiosis also provides combinative variability - the emergence of new combinations of hereditary inclinations during further fertilization.

The course of meiosis is controlled by the genotype of the organism, under the control of sex hormones (in animals), phytohormones (in plants) and many other factors (for example, temperature).

The following types of influences of some organisms on others are possible:

positive - one organism benefits at the expense of another;

negative - the body is harmed due to something else;

neutral - the other does not affect the body in any way.

Thus, the following options for relationships between two organisms are possible according to the type of influence they have on each other:

Mutualism - under natural conditions, populations cannot exist without each other (example: symbiosis of a fungus and algae in a lichen).

Proto-cooperation - the relationship is optional (example: the relationship between a crab and an anemone, the anemone protects the crab and uses it as a means of transportation).

Commensalism - one population benefits from the relationship, while the other receives neither benefit nor harm.

Cohabitation - one organism uses another (or its home) as a place of residence without causing harm to the latter.

Freeloading - one organism feeds on the leftover food of another.

Neutrality - both populations do not influence each other in any way.

Amensalism, antibiosis - one population negatively affects another, but does not itself experience a negative influence.

Predation is a phenomenon in which one organism feeds on the organs and tissues of another, without a symbiotic relationship.

Competition - both populations negatively influence each other.

Nature knows numerous examples of symbiotic relationships from which both partners benefit. For example, the symbiosis between leguminous plants and soil bacteria Rhizobium is extremely important for the nitrogen cycle in nature. These bacteria - also called nitrogen-fixing bacteria - settle on the roots of plants and have the ability to “fix” nitrogen, that is, to break down the strong bonds between the atoms of atmospheric free nitrogen, making it possible to incorporate nitrogen into compounds accessible to the plant, such as ammonia. In this case, the mutual benefit is obvious: the roots are a habitat for bacteria, and the bacteria supply the plant with the necessary nutrients.

There are also numerous examples of symbiosis that is beneficial for one species and does not bring any benefit or harm to another species. For example, the human intestine is inhabited by many types of bacteria, the presence of which is harmless to humans. Similarly, plants called bromeliads (which include pineapple, for example) live on tree branches but get their nutrients from the air. These plants use the tree for support without depriving it of nutrients.

Flatworms. Morphology, systematics, main representatives. Development cycles. Routes of infection. Prevention

Flatworms are a group of organisms, which in most modern classifications have the rank of phylum, uniting a large number of primitive worm-like invertebrates that do not have a body cavity. In its modern form, the group is clearly paraphyletic, but the current state of research does not make it possible to develop a satisfactory strictly phylogenetic system, and therefore zoologists traditionally continue to use this name.

The most famous representatives of flatworms are planaria (Turbellaria: Tricladida), liver fluke and cat fluke (trematodes), bovine tapeworm, pork tapeworm, broad tapeworm, echinococcus (tapeworms).

The question of the systematic position of the so-called intestinal turbellarians (Acoela) is currently being debated, since in 2003 it was proposed to distinguish them into an independent phylum.

The body is bilaterally symmetrical, with clearly defined head and caudal ends, somewhat flattened in the dorsoventral direction, in large representatives it is strongly flattened. The body cavity is not developed (except for some phases of the life cycle of tapeworms and flukes). Gases are exchanged across the entire surface of the body; respiratory organs and blood vessels are absent.

The outside of the body is covered with single-layer epithelium. In ciliated worms, or turbellarians, the epithelium consists of cells bearing cilia. Flukes, monogeneans, cestodes and tapeworms lack ciliated epithelium for most of their lives (although ciliated cells can be found in larval forms); their integument is represented by the so-called tegument, which in some groups carries microvilli or chitinous hooks. Flatworms that have a tegument are classified as Neodermata.

Under the epithelium there is a muscular sac, consisting of several layers of muscle cells that are not differentiated into individual muscles (certain differentiation is observed only in the area of ​​the pharynx and genital organs). The cells of the outer muscle layer are oriented transversely, while the cells of the inner layer are oriented along the anterior-posterior axis of the body. The outer layer is called the circular muscle layer, and the inner layer is called the longitudinal muscle layer.

In all groups, except for the cestodes and tapeworms, there is a pharynx leading to the gut or, as in the so-called intestinal turbellarians, to the digestive parenchyma. The intestine is blindly closed and communicates with the environment only through the mouth opening. Several large turbellarians have been noted to have anal pores (sometimes several), but this is rather the exception than the rule. In small forms the intestine is straight, in large ones (planaria, flukes) it can be highly branched. The pharynx is located on the abdominal surface, often in the middle or closer to the posterior end of the body, in some groups it is shifted forward. Cestode-shaped and tapeworms do not have a gut.

The nervous system is of the so-called orthogonal type. Most have six longitudinal trunks (two each on the dorsal and ventral sides of the body and two on the sides), connected by transverse commissures. Along with the orthogon, there is a more or less dense nerve plexus located in the peripheral layers of the parenchyma. Some of the most archaic representatives of ciliated worms have only a neural plexus.

A number of forms have developed simple light-sensitive ocelli, incapable of object vision, as well as organs of balance (stagocysts), tactile cells (sensilla) and chemical sense organs.

Osmoregulation is carried out with the help of protonephridia - branching channels connecting into one or two excretory channels. The release of toxic metabolic products occurs either with fluid excreted through protonephridia, or through accumulation in specialized parenchyma cells (atrocytes), which play the role of “storage buds”.

The vast majority of representatives are hermaphrodites, except for blood flukes (schistosomas) - they are dioecious. Fluke eggs are light yellow to dark brown in color and have a cap on one of the poles. During examination, eggs are found in duodenal contents, feces, urine, and sputum.

The first intermediate host of flukes are various mollusks, the second host is fish and amphibians. The definitive hosts are various vertebrates.

The life cycle (using the example of polymouth) is extremely simple: a larva emerges from the egg, leaving the fish, which after a short period of time again attaches itself to the fish and turns into an adult worm. Flukes have a more complex development cycle, changing 2-3 hosts.

Genotype. Genome. Phenotype. Factors determining the development of the phenotype. Dominance and recessivity. Interaction of genes in the determination of traits: dominance, intermediate manifestation, codominance

Genotype is a set of genes of a given organism, which, unlike the concepts of genome and gene pool, characterizes an individual, not a species (another difference between a genotype and a genome is the inclusion in the concept of “genome” of non-coding sequences that are not included in the concept of “genotype”). Together with environmental factors, it determines the phenotype of the organism.

Typically, a genotype is spoken of in the context of a specific gene; in polyploid individuals, it denotes a combination of alleles of a given gene. Most genes appear in the phenotype of an organism, but the phenotype and genotype differ in the following respects:

1. According to the source of information (the genotype is determined by studying the DNA of an individual, the phenotype is recorded by observing the appearance of the organism).

2. The genotype does not always correspond to the same phenotype. Some genes appear in phenotype only under certain conditions. On the other hand, some phenotypes, such as animal coat color, are the result of the interaction of several genes.

Genome - the totality of all the genes of an organism; its complete chromosome set.

It is known that DNA, which is the carrier of genetic information in most organisms and, therefore, forms the basis of the genome, includes not only genes in the modern sense of the word. Most of the DNA of eukaryotic cells is represented by non-coding (“redundant”) nucleotide sequences that do not contain information about proteins and RNA.

Consequently, the genome of an organism is understood as the total DNA of the haploid set of chromosomes and each of the extrachromosomal genetic elements contained in an individual cell of the germ line of a multicellular organism. The sizes of the genomes of organisms of different species differ significantly from each other, and there is often no correlation between the level of evolutionary complexity of a biological species and the size of its genome.

Phenotype is a set of characteristics inherent in an individual at a certain stage of development. The phenotype is formed on the basis of the genotype, mediated by a number of environmental factors. In diploid organisms, dominant genes appear in the phenotype.

Phenotype is a set of external and internal characteristics of an organism acquired as a result of ontogenesis (individual development)

Despite its seemingly strict definition, the concept of phenotype has some uncertainties. First, most of the molecules and structures encoded by genetic material are not visible in the external appearance of the organism, although they are part of the phenotype. For example, human blood types. Therefore, the expanded definition of phenotype should include characteristics that can be detected by technical, medical or diagnostic procedures. A further, more radical extension could include learned behavior or even the organism's influence on the environment and other organisms.

Phenotype can be defined as the “carrying out” of genetic information towards environmental factors. To a first approximation, we can talk about two characteristics of the phenotype: a) the number of directions of removal characterizes the number of environmental factors to which the phenotype is sensitive - the dimension of the phenotype; b) the “distance” of removal characterizes the degree of sensitivity of the phenotype to a given environmental factor. Together, these characteristics determine the richness and development of the phenotype. The more multidimensional the phenotype and the more sensitive it is, the further the phenotype is from the genotype, the richer it is. If we compare a virus, a bacterium, an ascaris, a frog and a human, then the richness of the phenotype in this series increases.

Some characteristics of the phenotype are directly determined by the genotype, such as eye color. Others are highly dependent on the organism's interaction with its environment—for example, identical twins may differ in height, weight, and other basic physical characteristics despite carrying the same genes.

Phenotypic variance (determined by genotypic variance) is a basic prerequisite for natural selection and evolution. The organism as a whole leaves (or does not leave) offspring, so natural selection influences the genetic structure of the population indirectly through the contributions of phenotypes. Without different phenotypes there is no evolution. At the same time, recessive alleles are not always reflected in the characteristics of the phenotype, but are preserved and can be transmitted to offspring.

The factors on which phenotypic diversity, the genetic program (genotype), environmental conditions and the frequency of random changes (mutations) depend are summarized in the following relationship:

genotype + external environment + random changes → phenotype.

The ability of a genotype to form different phenotypes in ontogenesis, depending on environmental conditions, is called the reaction norm. It characterizes the share of participation of the environment in the implementation of the characteristic. The wider the reaction norm, the greater the influence of the environment and the less the influence of the genotype in ontogenesis. Typically, the more diverse the habitat conditions of a species, the wider its reaction norm.

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Dominance (dominance) is a form of relationship between the alleles of one gene, in which one of them (dominant) suppresses (masks) the manifestation of the other (recessive) and thus determines the manifestation of the trait in both dominant homozygotes and heterozygotes.

With complete dominance, the phenotype of a heterozygote does not differ from the phenotype of a dominant homozygote. Apparently, in its pure form, complete dominance is extremely rare or does not occur at all.

With incomplete dominance, heterozygotes have a phenotype intermediate between the phenotypes of a dominant and recessive homozygote. For example, when pure lines of snapdragons and many other species of flowering plants with purple and white flowers are crossed, the first generation individuals have pink flowers. At the molecular level, the simplest explanation for incomplete dominance may be just a twofold decrease in the activity of an enzyme or other protein (if the dominant allele produces a functional protein, and the recessive allele produces a defective one). There may be other mechanisms of incomplete dominance.

In case of incomplete dominance, the same splitting by genotype and phenotype will be in the ratio 1: 2: 1.

With codominance, in contrast to incomplete dominance, in heterozygotes the characteristics for which each of the alleles is responsible appear simultaneously (mixed). A typical example of codominance is the inheritance of ABO blood groups in humans. All offspring of people with genotypes AA (second group) and BB (third group) will have the AB genotype (fourth group). Their phenotype is not intermediate between the phenotypes of their parents, since both agglutinogens (A and B) are present on the surface of erythrocytes. When codominance occurs, it is impossible to call one of the alleles dominant and the other recessive; these concepts lose their meaning: both alleles equally influence the phenotype. At the level of RNA and protein products of genes, apparently, the vast majority of cases of allelic interactions of genes are codominance, because each of the two alleles in heterozygotes usually encodes an RNA and/or a protein product, and both proteins or RNA are present in the body.

Environmental factors, their interaction

An environmental factor is a condition of the environment that affects the body. The environment includes all bodies and phenomena with which the organism is in direct or indirect relationships.

The same environmental factor has different significance in the life of co-living organisms. For example, the salt regime of the soil plays a primary role in the mineral nutrition of plants, but is indifferent to most terrestrial animals. The intensity of illumination and the spectral composition of light are extremely important in the life of phototrophic plants, and in the life of heterotrophic organisms (fungi and aquatic animals), light does not have a noticeable effect on their life activity.

Environmental factors affect organisms in different ways. They can act as irritants that cause adaptive changes in physiological functions; as limiters that make it impossible for certain organisms to exist under given conditions; as modifiers that determine morphological and anatomical changes in organisms.

It is customary to distinguish between biotic, anthropogenic and abiotic environmental factors.

Biotic factors are the entire set of environmental factors associated with the activities of living organisms. These include phytogenic (plants), zoogenic (animals), microbiogenic (microorganisms) factors.

Anthropogenic factors are all the many factors associated with human activities. These include physical (the use of nuclear energy, travel on trains and planes, the influence of noise and vibration, etc.), chemical (the use of mineral fertilizers and pesticides, pollution of the earth’s shells with industrial and transport waste; smoking, drinking alcohol and drugs, excessive use of medicines). means), biological (food; organisms for which a person can be a habitat or source of nutrition), social (related to relationships between people and life in society) factors.

Abiotic factors are all the many factors associated with processes in inanimate nature. These include climatic (temperature, humidity, pressure), edaphogenic (mechanical composition, air permeability, soil density), orographic (relief, altitude above sea level), chemical (gas composition of air, salt composition of water, concentration, acidity), physical (noise, magnetic fields, thermal conductivity, radioactivity, cosmic radiation).

When environmental factors act independently, it is enough to use the concept of “limiting factor” to determine the combined impact of a complex of environmental factors on a given organism. However, in real conditions, environmental factors can enhance or weaken each other's effects.

Taking into account the interaction of environmental factors is an important scientific problem. Three main types of interaction of factors can be distinguished:

additive - the interaction of factors is a simple algebraic sum of the effects of each factor when acting independently;

synergetic - the joint action of factors enhances the effect (that is, the effect when they act together is greater than the simple sum of the effects of each factor when acting independently);

antagonistic - the joint action of factors weakens the effect (that is, the effect of their joint action is less than the simple sum of the effects of each factor).

List of used literature

Gilbert S. Developmental biology. - M., 1993.

Green N., Stout W., Taylor D. Biology. - M., 1993.

Nebel B. Environmental Science. - M., 1993.

Carroll R. Paleontology and evolution of vertebrates. - M., 1993.

Leninger A. Biochemistry. - M., 1974.

Slyusarev A.A. Biology with general genetics. - M., 1979.

Watson D. Molecular biology of the gene. - M., 1978.

Chebyshev N.V., Supryaga A.M. Protozoa. - M., 1992.

Chebyshev N.V., Kuznetsov S.V. Cell biology. - M., 1992.

Yarygin V.N. Biology. - M., 1997.

Naturalistic Biology Aristotle: -Divided the animal kingdom into two groups: those with blood and those without blood. - Man is on top of blood animals (anthropocentrism). K. Linnaeus: -developed a harmonious hierarchy of all animals and plants (species - genus - order - class), -introduced precise terminology to describe plants and animals.

Evolutionary biology The question of the origin and essence of life. J. B. Lamarck proposed the first evolutionary theory in 1809. J. Cuvier proposed the theory of catastrophes. Charles Darwin evolutionary theory in 1859 evolutionary theory in 1859 Modern (synthetic) theory of evolution (represents a synthesis of genetics and Darwinism).

Molecular genetic level The level of functioning of biopolymers (proteins, nucleic acids, polysaccharides), etc., underlying the life processes of organisms. An elementary structural unit is a gene. The carrier of hereditary information is a DNA molecule.

Nucleic acids Complex organic compounds that are phosphorus-containing biopolymers (polynucleotides). Types: Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). An organism's genetic information is stored in DNA molecules. They have the property of molecular dissymmetry (asymmetry), or molecular chirality - they are optically active.

DNA consists of two strands twisted into a double helix. RNA contains 4-6 thousand individual nucleotides, DNA - thousands. A gene is a section of a DNA or RNA molecule.

Cellular level At this level, spatial delimitation and ordering of vital processes occurs due to the division of functions between specific structures. The basic structural and functional unit of all living organisms is the cell. The history of life on our planet began from this level of organization.

All living organisms consist of cells and their metabolic products. New cells are formed by dividing pre-existing cells. All cells are similar in chemical composition and metabolism. The activity of the organism as a whole consists of the activity and interaction of individual cells.

In the 1830s. The cell nucleus was discovered and described. All cells consist of: 1) a plasma membrane, which controls the transition of substances from the environment into the cell and back; 2) cytoplasms with a diverse structure; 3) the cell nucleus, which contains genetic information.

Ontogenetic (organismal) level An organism is an integral unicellular or multicellular living system capable of independent existence. Ontogenesis is the process of individual development of an organism from birth to death, the process of realizing hereditary information.

A population is a collection of individuals of the same species occupying a certain territory, reproducing itself over a long period of time and having a common genetic pool. A species is a collection of individuals that are similar in structure and physiological properties, have a common origin, and can freely interbreed and produce fertile offspring.

Biogeocenotic level Biogeocenosis, or ecological system (ecosystem) is a set of biotic and abiotic elements interconnected by the exchange of matter, energy and information, within which the circulation of substances in nature can take place.

Biogeocenosis is an integral self-regulating system consisting of: 1) producers (producers) that directly process inanimate matter (algae, plants, microorganisms); 2) consumers of the first order - matter and energy are obtained through the use of producers (herbivores); 3) second-order consumers (predators, etc.); 4) scavengers (saprophytes and saprophages), feeding on dead animals; 5) decomposers are a group of bacteria and fungi that decompose the remains of organic matter.

“Biosphere and Civilization” - Abiotic factors. Basic concepts of ecology. Environmental factor. Herbivores. American scientist. Book by V.I. Vernadsky "Biosphere". Human activity. Greenhouse effect. Ecological niche. Limiting factors. The lower boundary of the biosphere. Excess water. Eduard Suess. Autotrophs. Anthropogenic factor. Water consumption. Population growth. Position of the view in space. Compensatory properties.

“The concept of the biosphere” - Human reactions to changes in the biosphere. Malaria. Evolution of the biosphere. Living matter in the biosphere. Films of life in the ocean. Portrait of Jean-Baptiste Lamarck. Sargassum algae. How philosophers represent the noosphere. Decomposition of organics and inorganics. An example of failed human intervention. Noosphere. Alive organisms. Special chemical composition. Nitrogen cycle. Composition of the biosphere. Riftii. Anaerobic bacteria.

“Biosphere as a global ecosystem” - Biosphere as a global biosystem and ecosystem. Inanimate nature. Living environments of organisms on Earth. Man as an inhabitant of the biosphere. Shell of the Earth. Biological cycle. Environmental factors. Alive organisms. Human. Biosphere as a global biosystem. Features of the biosphere level of living matter.

“The biosphere is the living shell of the Earth” - Inanimate nature. The appearance of the ancient inhabitants of our planet. Alive organisms. Rocks. Vegetation cover. Warm. Biosphere. Earth. Green plants. Creatures.

“Composition and structure of the biosphere” - Boundaries of the biosphere. Evolutionary state. Vernadsky. Limiting factor. Hydrosphere. Earth shell. Living matter. Lithosphere. Ozone layer. Noosphere. Structure of the biosphere. Biosphere. Atmosphere.

“Study of the biosphere” - Bacteria, spores and pollen. Interaction. The origin of life on Earth. What is approximately the age of planet Earth. Viability. All organisms are united into 4 kingdoms of living nature. Diversity of organisms. 40 thousand years ago modern man appeared. How many types of mushrooms are there? Boundaries of the biosphere. Check yourself. What does the biosphere supply to the hydrosphere? Game "Biosphere". Diversity of organisms on Earth.

Slide 2

• Biology is the science of life and living nature.
• The main tasks are to give a scientific definition of life, to point out the fundamental difference between living and nonliving things, and to find out the specifics of the biological form of existence of matter.
• The main object of biological research is living matter.

Slide 3

Slide 4

STAGES OF BIOLOGY DEVELOPMENT

• period of systematics – naturalistic biology;
• evolutionary period – physical and chemical biology;
• The period of biology of the microworld is evolutionary biology.

Slide 5

Naturalistic biology

Aristotle:

He divided the animal kingdom into two groups: those with blood and those without blood.

Man is on top of blood animals (anthropocentrism).

K. Linnaeus:

• developed a harmonious hierarchy of all animals and plants (species - genus - order - class),
• introduced precise terminology to describe plants and animals.

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Physico-chemical biology

Understanding the mechanisms of phenomena and processes occurring at different levels of life and living organisms.

New theories have emerged:

• cell theory,
• cytology,
• genetics,
• biochemistry,
• biophysics.

Slide 7

Evolutionary biology

• The question of the origin and essence of life.
• J. B. Lamarck proposed the first evolutionary theory in 1809.
• J. Cuvier - the theory of catastrophes.
• Charles Darwin's theory of evolution in 1859
• Modern (synthetic) theory of evolution (represents a synthesis of genetics and Darwinism).

Slide 8

Darwin's theory of evolution

• variability
• heredity
• natural selection

Slide 9

Structural levels of life organization

• Cellular level
• Population-species level
• Biocenotic level
• Biogeocenotic level
• Biosphere level

Slide 10

Molecular genetic level

• The level of functioning of biopolymers (proteins, nucleic acids, polysaccharides), etc., underlying the life processes of organisms.
• Elementary structural unit - gene
• The carrier of hereditary information is the DNA molecule.

Slide 11

Objective: study of the mechanisms of transmission of genetic information, heredity and variability, study of evolutionary processes, the origin and essence of life.

Slide 12

• Macromolecules are giant polymer molecules built from many monomers.
• Polymers: polysaccharides, proteins and nucleic acids.
• Monomers for them are monosaccharides, amino acids and nucleotides.

Slide 13

• Polysaccharides (starch, glycogen, cellulose) are sources of energy and building material for the synthesis of larger molecules.
• Proteins and nucleic acids are “information” molecules.

Slide 14

Squirrels

• Macromolecules that are very long chains of amino acids.
• Most proteins perform the function of catalysts (enzymes).
• Proteins play the role of carriers.

Slide 15

Nucleic acids

• Complex organic compounds that are phosphorus-containing biopolymers (polynucleotides).
• Types: Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
• An organism's genetic information is stored in DNA molecules.
• They have the property of molecular dissymmetry (asymmetry), or molecular chirality - they are optically active.

Slide 16

• DNA consists of two strands twisted into a double helix.
• RNA contains 4-6 thousand individual nucleotides, DNA - 10-25 thousand.
• A gene is a section of a DNA or RNA molecule.

Slide 17

Cellular level

• At this level, spatial delimitation and ordering of life processes occurs due to the division of functions between specific structures.
• The basic structural and functional unit of all living organisms is the cell.
• The history of life on our planet began from this level of organization.

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A cell is a natural grain of life, just as an atom is a natural grain of unorganized matter. Teilhard de Chardin

Slide 19

• A cell is an elementary biological system capable of self-renewal, self-reproduction and development.
• The science that studies living cells is called cytology.
• The cell was first described by R. Hooke in 1665.

Slide 20

• All living organisms consist of cells and their metabolic products.
• New cells are formed by dividing pre-existing cells.
• All cells are similar in chemical composition and metabolism.
• The activity of the organism as a whole consists of the activity and interaction of individual cells.

Slide 21

In the 1830s. The cell nucleus was discovered and described.

All cells consist of:

• the plasma membrane, which controls the transition of substances from the environment into the cell and back;
• cytoplasm with a diverse structure;
• the cell nucleus, which contains genetic information.

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The structure of an animal cell

Slide 23

• Cells can exist as independent organisms or as part of multicellular organisms.
• A living organism is formed by billions of different cells (up to 1015).
• The cells of all living organisms are similar in chemical composition.

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Depending on the cell type, all organisms are divided into two groups:

1) prokaryotes - cells lacking a nucleus, such as bacteria;

2) eukaryotes - cells containing nuclei, such as protozoa, fungi, plants and animals.

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Ontogenetic (organismal) level

• An organism is an integral unicellular or multicellular living system capable of independent existence.
• Ontogenesis is the process of individual development of an organism from birth to death, the process of realizing hereditary information.

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• Physiology is the science of the functioning and development of multicellular living organisms.
• The process of ontogeny is described on the basis of the biogenetic law formulated by E. Haeckel.

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An organism is a stable system of internal organs and tissues existing in the external environment.

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Population-species level

• It begins with the study of the relationship and interaction between sets of individuals of the same species that have a single gene pool and occupy a single territory.
• The basic unit is the population.

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The population level extends beyond the individual organism and is therefore called the supraorganismal level of organization.

Slide 30

• A population is a collection of individuals of the same species occupying a certain territory, reproducing itself over a long period of time and having a common genetic pool.
• A species is a collection of individuals that are similar in structure and physiological properties, have a common origin, and can freely interbreed and produce fertile offspring.

Biogeocenosis, or ecological system (ecosystem) is a set of biotic and abiotic elements interconnected by the exchange of matter, energy and information, within which the circulation of substances in nature can take place.

Slide 35

Biogeocenosis is an integral self-regulating system consisting of:

• producers (manufacturers) who directly process non-living matter (algae, plants, microorganisms);
• first-order consumers - matter and energy are obtained through the use of producers (herbivores);
• second-order consumers (predators, etc.);
• scavengers (saprophytes and saprophages), feeding on dead animals;
• decomposers are a group of bacteria and fungi that decompose the remains of organic matter.

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Biosphere level

• The highest level of organization of life, covering all phenomena of life on our planet.
• The biosphere is the living matter of the planet (the totality of all living organisms on the planet, including humans) and the environment transformed by it.

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• The biosphere is a single ecological system.
• Studying the functioning of this system, its structure and functions is the most important task of biology.
• Ecology, biocenology and biogeochemistry study these problems.

Slide 38

Each level of organization of living matter has its own specific features, therefore, in any biological research, a certain level is leading.

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