Levels of organization of living systems. Cellular level. Basic provisions

modern cell theory.

Molecular genetic level (elementary unit - gene)

Cellular level (cell)

Organism level, otherwise ontogenetic (individual)

Population-species (population)

Biogeocenotic (biogeocenoses)

The cellular level is the level of cells (cells of bacteria, cyanobacteria, unicellular animals and algae, unicellular fungi, cells of multicellular organisms). Elementary phenomena are represented by reactions of cellular metabolism. Thanks to the activity of the cell, substances coming from outside are converted into substrates and energy, which are utilized in the process of protein biosynthesis in accordance with existing information. thus, at the cellular level, the mechanisms of information transfer and the transformation of substances and energy are conjugated. Elementary phenomena at this level create the energy and material basis of life at other levels. A cell is a structural unit of the living, a functional unit, a unit of development. This level is studied by cytology, cytochemistry, cytogenetics, microbiology. Modern cell theory includes the following main provisions:

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

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

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

#4 New cells are formed only as a result of the division of the original cells;

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

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

Structural and functional organization of pro- and eukaryotic cells.

Cells of the prokaryotic type are especially small in size (no more than 0.5-3.0 microns in diameter). they do not have a morphologically distinct nucleus; nuclear material in the form of DNA is not separated from the cytoplasm by a membrane. The cell lacks a developed system of membranes. The genetic apparatus is formed by a single ring chromosome, which is devoid of the main histone proteins. Prokaryotes lack a cell center. For them, intracellular movements of the cytoplasm and amoeboid movement are not typical. The time required for the formation of two daughter cells (generation time) is relatively short and amounts to tens of minutes. Prokaryotic cells do not divide by mitosis. This cell type includes bacteria and blue-green algae. The eukaryotic type of cellular organization is represented by two subtypes. A feature of protozoan organisms is that they (excluding colonial forms) correspond structurally to the level of one cell, and physiologically to a full-fledged individual. In this regard, one of the features of the cells of a part of the protozoa is the presence in the cytoplasm of miniature formations that perform the functions of the vital organs of a multicellular organism at the cellular level. These are (for example, in ciliates) cytostome, cytopharyngs and powder, similar to the digestive system, and contractile vacuoles, similar to the excretory system. The cells of multicellular organisms have a membrane. The plasmalemma (cell membrane) is formed by a membrane covered on the outside with a layer of glycocalyx. The cell has a nucleus and cytoplasm. The nucleus has a membrane, nuclear juice, nucleolus, chromatin. The cytoplasm is represented by the main substance (matrix, hyaloplasm), in which inclusions and organelles are distributed (rough and smooth eps, lamellar complex, mitochondria, ribosomes, polysomes, lysosomes, perixisomes, microfibrils, microtubules, centrioles of the cell center. Chloroplasts are also isolated in plant cells .
In the traditional presentation, a cell of a plant or animal organism is described as an object, delimited by a shell, in which the nucleus and cytoplasm are isolated. In the nucleus, along with the membrane and nuclear juice, the nucleolus and chromatin are found. The cytoplasm is represented by its main substance (matrix, hyaloplasm), in which inclusions and organelles are distributed.

The life cycle of a cell. Its periods for cells with different degrees

Differentiations.

FCC is the period of a cell's life from its formation (by dividing the mother cell) to its division or death.

FCC capable of dividing cells:

Mitotic cycle: -autocatalytic phase - preparation for division. consists of period G1(synthetic), S(synthetic) , G2(postsynthetic).

In a multicellular organism, there are cells that, after their birth, enter a period of rest G0 (these are cells that perform specific functions as part of a particular function)

FCC of non-dividing cells:

heterocatalytic interphase

mitotic cycle. Mitosis. The biological significance of mitosis. Possible

pathology of mitosis.

The mitotic cycle consists of autocatalytic interphase(G1-chromosomes are decondensed, proteins and RNA accumulate, the number of mitochondria increases,; S- DNA replication, protein and RNA synthesis continues;, G2- DNA synthesis stops, energy accumulates, RNA and proteins are synthesized that form fission spindle threads) and mitosis:

Prophase 2n4c - the nuclear membrane dissolves, the nucleolus disappears, condensation and despiralization of chromosomes occurs.

Metaphase of the 2n4c chromosome at the equator of the cell.

Anaphase 4n4c - chromatids diverge towards the poles of the cell.

Telophase 2n2c - formation of the nucleolus, cytotomy, the formation of two daughter cells. The biological significance of mitosis.

The biological significance of mitosis is enormous. The constancy of the structure and the correct functioning of the organs and tissues of a multicellular organism would be impossible without the preservation of an identical set of genetic material in countless cell generations. Mitosis provides important life phenomena, such as embryonic development, growth, restoration of organs and tissues after damage, maintenance of the structural integrity of tissues with constant loss of cells in the course of their functioning (replacement of dead red blood cells, exfoliated skin cells, etc.). Pathologies of mitosis:

Violation of chromosome condensation leads to swelling and adhesion of chromosomes

Damage to the spindle is the cause of the delay in mitosis in metaphase and the dispersion of chromosomes.

Violation of the divergence of chromatids in the anaphase of mitosis leads to the appearance of cells with a different number of chromosomes

In the absence of cytotomy at the end of telophase, bi- and multinucleated cells are formed.

reproduction at the molecular level. DNA replication in pro- and eukaryotes.

One of the main functions of DNA is the preservation and transmission of hereditary information. This function is based on the ability of DNA to copy itself - replication. As a result of replication, from one parent DNA molecule, two daughter DNA molecules are formed - copies of the parent.

Helicase unwinds the DNA double helix

Destabilizing proteins - straighten DNA strands

DNA topoisomerase - breaks phosphodiester bonds in one of the DNA chains, relieves the tension of the helix.

RNA primase - provides the synthesis of RNA primer for Okazaki fragments

DNA polymerase - synthesis of a polynucleotide chain in the 5-3 direction

DNA ligase - stitches together Okazaki fragments after removal of the DNA primer.

The concept of DNA repair.

spermatogenesis

Phases of spermatogenesis, their essence. Place of spermatogenesis in human ontogenesis.

polygenic inheritance. The concept of MFB. An example of a polygenic inherited disease in dentistry.

Inheritance of traits in the polymeric interaction of genes. In the case when a complex trait is determined by several pairs of genes in the genotype and their interaction is reduced to the accumulation of the effect of the action of certain alleles of these genes, in the offspring of heterozygotes, a different degree of expression of the trait is observed, depending on the total dose of the corresponding alleles. For example, the degree of skin pigmentation in humans, determined by four pairs of genes, ranges from the most pronounced in homozygotes for dominant alleles in all four pairs (P 1 P 1 P 2 P 2 P 3 P 3 P 4 P 4) to the minimum in homozygotes for recessive alleles. alleles (p 1 p 1 p 2 p 2 p 3 p 3 p 4 p 4) (see Fig. 3.80). When two mulattos are married, heterozygous for all four pairs, which form 2 4 = 16 types of gametes, offspring are obtained, 1/256 of which has maximum skin pigmentation, 1/256 - minimum, and the rest are characterized by intermediate indicators of expressivity of this trait. In the analyzed example, the dominant alleles of the polygenes determine pigment synthesis, while the recessive alleles practically do not provide this feature. The skin cells of organisms homozygous for the recessive alleles of all genes contain the minimum amount of pigment granules.

In some cases, dominant and recessive alleles of polygenes can provide the development of different variants of traits. For example, in the shepherd's purse plant, two genes have the same effect on determining the shape of the pod. Their dominant alleles form one, and recessive alleles form another form of pods. When two diheterozygotes are crossed for these genes (Fig. 6.16), a 15:1 split is observed in the offspring, where 15/16 offspring have from 1 to 4 dominant alleles, and 1/16 do not have dominant alleles in the genotype.

Many hereditary traits cannot be given a sufficiently accurate qualitative description. Gradual subtle transitions are observed between individuals, and during splitting there are no clearly demarcated phenotypic classes. Such signs are studied by measurements or calculations that allow giving a digital characteristic to the sign. For example, body weight and size, fertility, yield, productivity, precocity, protein and fat content, etc. These are quantitative signs.

And although there is no clear boundary between qualitative and quantitative traits (some quantitative traits can be described as qualitative: high - dwarf "early ripening - late ripening, and qualitative ones can be expressed quantitatively, for example, differences in color - the amount of pigment), three important features of quantitative traits can be distinguished :

1) continuous variation;

2) dependence on a large number of interacting genes;

3) dependence on the external environment, that is, a strong susceptibility to the influence of modification variability, the result of which is continuous, which does not yet blur phenotypic differences between genotypic classes.

The bulk of the features "with which the breeder has to deal are quantitative.

An important feature of polygenic inheritance is that the more genons that affect a trait, the more continuous the variability of this trait will be. And variability due to the influence of external conditions makes the distribution of quantitative traits even smoother and more continuous. As a result, the distribution of variability of quantitative traits is close to normal, those genotypes that determine intermediate options are more than genotypes that determine extreme options.

Cytogenetic method

The cytogenetic method is used to study the normal human karyotype, as well as in the diagnosis of hereditary diseases associated with genomic and chromosomal mutations.
In addition, this method is used in the study of the mutagenic action of various chemicals, pesticides, insecticides, drugs, etc.
During cell division at the metaphase stage, chromosomes have a clearer structure and are available for study. The human diploid set consists of 46 chromosomes:
22 pairs of autosomes and one pair of sex chromosomes (XX in women, XY in men). Usually, human peripheral blood leukocytes are examined, which are placed in a special nutrient medium, where they divide. Then preparations are prepared and the number and structure of chromosomes are analyzed. The development of special staining methods has greatly simplified the recognition of all human chromosomes, and in combination with the genealogical method and methods of cell and genetic engineering, it has made it possible to correlate genes with specific regions of chromosomes. The complex application of these methods underlies the mapping of human chromosomes.

Cytological control is necessary for the diagnosis of chromosomal diseases associated with ansuploidy and chromosomal mutations. The most common are Down's disease (trisomy on the 21st chromosome), Klinefelter's syndrome (47 XXY), Shershevsky-Turner syndrome (45 XO), etc. Loss of a section of one of the homologous chromosomes of the 21st pair leads to a blood disease - chronic myeloid leukemia.

Cytological studies of the interphase nuclei of somatic cells can reveal the so-called Barr body, or sex chromatin. It turned out that sex chromatin is normally present in women and absent in men. It is the result of heterochromatization of one of the two X chromosomes in females. Knowing this feature, it is possible to identify gender and identify an abnormal number of X chromosomes.

The detection of many hereditary diseases is possible even before the birth of a child. The method of prenatal diagnosis consists in obtaining amniotic fluid, where the cells of the fetus are located, and in the subsequent biochemical and cytological determination of possible hereditary anomalies. This allows you to make a diagnosis in the early stages of pregnancy and decide whether to continue or terminate it.

Adaptation (from Latin adaptatio - adaptation) is a dynamic process due to which the mobile systems of living organisms, despite the variability of conditions, maintain the stability necessary for the existence, development and procreation. It is the mechanism of adaptation, developed as a result of long-term evolution, that ensures the possibility of the existence of an organism in constantly changing environmental conditions.

1. Human biological adaptation acclimatizations

2. Social adaptation- the process of active adaptation of an individual (a group of individuals) to the social environment, manifested in the provision of conditions conducive to the realization of his needs, interests, life goals. Social adaptation includes adaptation primarily to the conditions and nature of work (study), as well as to the nature of interpersonal relationships, the ecological and cultural environment, leisure activities, and everyday life. The process of social adaptation is closely related to the process socialization individual, internalization of social and group norms. Social adaptation involves both the adaptation of the individual to the conditions of life (passive adaptation), and their active purposeful change (active adaptation). It has been empirically established that the dominance of the second of these types of adaptive behavior in an individual determines a more successful course of social adaptation. The relationship between the nature of the value orientations of the individual and the type of adaptive behavior has also been revealed. So, people focused on the manifestation and improvement of their abilities are dominated by an attitude towards active-transformative interaction with the social environment, people focused on material well-being - selectivity, targeted limitation of social activity, people focused on comfort - adaptive behavior. Value orientations also determine the requirements of the individual to the nature and conditions of work, life, leisure, the nature of interpersonal communication. For example, the monotonous work on the assembly line, as a rule, has a depressing effect on people with a high educational level, but satisfies workers with a low level of education and qualifications.

Acclimatization - adaptation of organisms to new conditions of existence after territorial, artificial or natural movement with the formation of stable reproducing groups of organisms (populations); is a special case of acclimatization.

Acclimatization in a hot climate may be accompanied by loss of appetite, intestinal disturbance, sleep disturbance, and a decrease in resistance to infectious diseases. The noted functional deviations are due to a violation of water-salt metabolism. Muscle tone decreases, sweating increases, urination decreases, breathing, pulse, etc. become more frequent. As air humidity increases, the tension of adaptation mechanisms increases.

Climatic extremeness for the living conditions of the population in extremely cold climates is created by:

· High frequency (45-65% of days per year) of low negative temperatures.

Lack or complete absence (polar night) of solar radiation in winter.

· Predominance of cloudy weather (140-150 days per year).

· Strong winds with frequent blowing blizzards.

36. Biological adaptation. Mechanisms of urgent and long-term adaptation.

The concept of constitutional types.

Human biological adaptation- evolutionarily arisen adaptation of the human body to environmental conditions, expressed in a change in the external and internal features of an organ, function or the whole organism to changing environmental conditions. In the process of adapting an organism to new conditions, two processes are distinguished - phenotypic or individual adaptation, which is more correctly called acclimatizations(see) and the genotypic adaptation which is carried out by natural selection of signs, useful to a survival. With phenotypic adaptation, the body directly reacts to the new environment, which is expressed in phenotypic shifts, compensatory physiological changes that help the body maintain balance with the environment under new conditions. Upon transition to the previous conditions, the previous state of the phenotype is also restored, compensatory physiological changes disappear. With genotypic adaptation, deep morpho-physiological changes occur in the body, which are inherited and fixed in the genotype as new hereditary characteristics of populations, ethnic groups and races.

Specific adaptive mechanisms inherent in a person give him the opportunity to endure a certain range of deviations of factors from optimal values ​​without disturbing the normal functions of the body.

The urgent stage of adaptation occurs immediately after the onset of the stimulus on the body and can be realized only on the basis of previously formed physiological mechanisms. Examples of manifestations of urgent adaptation are: a passive increase in heat production in response to cold, an increase in heat transfer in response to heat, an increase in pulmonary ventilation and minute volume of blood circulation in response to a lack of oxygen. At this stage of adaptation, the functioning of organs and systems proceeds at the limit of the physiological capabilities of the body, with almost complete mobilization of all reserves, but without providing the most optimal adaptive effect. Thus, the running of an untrained person occurs at close to the maximum values ​​of the minute volume of the heart and pulmonary ventilation, with the maximum mobilization of the reserve of glycogen in the liver. The biochemical processes of the body, their speed, as it were, limit this motor reaction, it can neither be fast enough, nor long enough;

Long-term adaptation to a long-acting stressor occurs gradually, as a result of a long-term, constant or repeated action of environmental factors on the body. The main conditions for long-term adaptation are the consistency and continuity of the impact of an extreme factor. In essence, it develops on the basis of repeated implementation of urgent adaptation and is characterized by the fact that as a result of constant quantitative accumulation of changes, the body acquires a new quality - from an unadapted one it turns into an adapted one. Such is adaptation to previously unattainable intense physical work (training), the development of resistance to significant high-altitude hypoxia, which was previously incompatible with life, the development of resistance to cold, heat, and large doses of poisons. This is the same mechanism and qualitatively more complex adaptation to the surrounding reality.

Currently, there is no generally accepted theory and classification of constitutions. The variety of approaches proposed by different specialists gives rise to many assessments, definitions of the constitution, reflects the complexity of the problems facing constitutionalism. To date, the most successful and complete definition of the constitution is the following. Constitution (lat. constitutia - establishment, organization) is a complex of individual relatively stable morphological, physiological and mental properties of the body, due to heredity, as well as long-term and intense environmental influences, manifested in its reactions to various influences (including social and pathogenic).

In our country, the most widespread classification proposed by M.V. Chernorutsky. He identified three types of constitution:

1) asthenic;

2) normosthenic;

3) hypersthenic

Assignment to one or another type was made on the basis of the value of the Pinier index (body length - (mass + chest volume at rest). In asthenics, the Pinier index is more than 30, in hypersthenics it is less than 10, in normosthenics it ranges from 10 to 30. These three types constitutions are characterized not only by the features of external morphological features, but also by functional properties.

37. Ecological differentiation of mankind. The concept of races and adaptive

types of people.

38. Adaptive types of people. Morphofunctional characteristic

representatives of alpine and arid types.

adaptive type
represents the rate of biological response to a set of environmental conditions
environment and is manifested in the development of morphofunctional, biochemical and
immunological traits that provide optimal adaptability to
given living conditions.

The complexes of signs of adaptive types from different geographical areas include common and specific elements. The former include, for example, indicators
bone-muscular body mass, the amount of immune proteins in blood serum
person. Such elements increase the overall resistance of the body to
unfavorable environmental conditions. Specific elements vary
and are closely related to the prevailing conditions in a given habitat - hypoxia, hot or cold climate.
It is their combination that serves as the basis for the allocation of adaptive types:
arctic, tropical, temperate zone, alpine, desert and
others

Let us analyze the features of the living conditions of human populations in various
climatic and geographical zones and adaptive types of people formed in them.

High altitude conditions are extreme for humans in many respects. They are characterized by low atmospheric pressure, reduced partial pressure of oxygen, cold, and the relative uniformity of food. The main environmental factor in the formation mountain adaptive type appeared to be hypoxia. Residents of the highlands, regardless of the climatic zone, race and ethnicity, have an increased level of basal metabolism, relative elongation of the long tubular bones of the skeleton, expansion of the chest, an increase in the oxygen capacity of the blood due to an increase in the number of red blood cells, hemoglobin content and the relative ease of its transition to oxyhemoglobin.

Arid adaptive type formed among the inhabitants of the desert. For the desert, the main harmful factor is the effect of dry air, which has a large evaporative capacity. In addition, in tropical deserts there is a strong year-round thermal effect, and in the extratropical zone, sharp seasonal temperature changes - hot in summer and cold in winter. Under these conditions, as well as in the tropics, long-bodied morphotypes are more common (up to 70%), the muscle and fat components develop poorly, but the overall body size of the desert inhabitants is larger. Their basal metabolic rate is low, the amount of cholesterol in the blood is reduced

46. ​​Transmissible and non-transmissible natural focal diseases.

Ecological bases for their selection.

47. Subject of medical helminthology. The concept of geo- and biohelminths,

anthroponoses and zoonoses.

46. ​​NATURAL FOCAL DISEASES

1) pathogens circulate in nature from one animal to another, regardless of man;

2) the reservoir of the pathogen is wild animals;

3) diseases are not distributed everywhere, but in a limited area with a certain landscape, climatic factors and biogeocenoses.

Components natural focus are:

1) pathogen;

2) animals susceptible to the pathogen - reservoirs:

3) the corresponding complex of natural and climatic conditions in which this biogeocenosis exists.

A special group of natural focal diseases are vector-borne diseases such as leishmaniasis, trypanosomiasis, tick-borne encephalitis, etc. Therefore, the presence of a carrier is also an obligatory component of the natural focus of a vector-borne disease.

Transmissible diseases are contagious human diseases, the pathogens of which are transmitted by blood-sucking arthropods (insects and mites).

Transmissible diseases include more than 200 nosological forms caused by viruses, bacteria, rickettsiae, protozoa and helminths. Some of them are transmitted only with the help of blood-sucking vectors (obligate vector-borne diseases, such as typhus, malaria, etc.), some in various ways, including transmissively (for example, tularemia, which is infected by mosquito and tick bites, as well as skinning sick animals).

carriers

infected with viruses, in ticks infected with viruses, rickettsia and spirochetes, and in mosquitoes infected with phleboviruses.

In the body of mechanical carriers, pathogens do not develop and do not multiply. Once on the proboscis, in the intestines or on the surface of the body of a mechanical carrier, the pathogen is transmitted directly (with a bite) or by contamination of wounds, mucous membranes of the host or food products.

Characteristics of the carrier and the mechanism of transmission of the pathogen

Area of ​​distribution and features of epidemiology

Prevention

Most vector-borne diseases are prevented by reducing the number of vectors. With the help of this measure, the USSR managed to eliminate such transmissible anthroponoses as lice relapsing fever, mosquito fever, and urban cutaneous leishmaniasis. Land reclamation work and the creation of zones around populated areas free from wild rodents and carriers of pathogens of transmissible diseases are of great importance.

Some natural focal diseases are characterized by endemism, i.e. occurrence in strictly limited areas. This is due to the fact that the causative agents of the corresponding diseases, their intermediate hosts, reservoir animals or carriers are found only in certain biogeocenoses.

A small number of natural focal diseases are found almost everywhere. These are diseases, the causative agents of which, as a rule, are not connected in the cycle of their development with the external environment and affect a wide variety of hosts. Such diseases include, for example, toxoplasmosis and trichinosis. A person can become infected with these natural-focal diseases in any natural-climatic zone and in any ecological system.

The vast majority of natural focal diseases affect a person only if he gets into the appropriate focus (hunting, fishing, hiking, geological parties, etc.) under conditions of his susceptibility to them. So, a person becomes infected with taiga encephalitis when bitten by an infected tick, and opisthorchiasis - by eating insufficiently thermally processed fish with cat fluke larvae.

Prevention of natural focal diseases presents particular challenges. Due to the fact that a large number of hosts, and often carriers, are included in the circulation of the pathogen, the destruction of entire biogeocenotic complexes that have arisen as a result of the evolutionary process is ecologically unreasonable, harmful, and even technically impossible. Only in cases where the foci are small and well studied, is it possible to complexly transform such biogeocenoses in a direction that excludes the circulation of the pathogen. Thus, the reclamation of desert landscapes with the creation of irrigated horticultural farms in their place, carried out against the backdrop of the fight against desert rodents and mosquitoes, can dramatically reduce the incidence of leishmaniasis in the population. In most cases of natural focal diseases, their prevention should be aimed primarily at individual protection (prevention from bites by blood-sucking arthropods, heat treatment of food products, etc.) in accordance with the circulation pathways in nature of specific pathogens.

Worms are multicellular, three-layered, protostomes, bilaterally symmetrical animals. Their body has an elongated shape, and the skin-muscular sac consists of smooth or striated muscles and integumentary tissues.

Helminths can live in humans in almost all organs. In accordance with this, the ways of their penetration into the human body, the symptoms of diseases and diagnostic methods are different.

The most difficult thing in life is with simplicity.

A. Koni

ELEMENTAL COMPOSITION OF ORGANISMS

Molecular level of life organization

- this is the level of organization, the properties of which are determined by chemical elements and molecules and their participation in the processes of transformation of substances, energy and information. The application of the structural-functional approach to understanding life at this level of organization allows us to identify the main structural components and processes that determine the structural and functional ordering of the level.

Structural organization of the molecular level. The elementary structural components of the molecular level of life organization are chemical elements as separate types of atoms, and not interconnected and with their own specific properties. The distribution of chemical elements in biosystems is determined precisely by these properties, and depends primarily on the magnitude of the charge of the nucleus. The science that studies the distribution of chemical elements and their significance for biosystems is called biogeochemistry. The founder of this science was the brilliant Ukrainian scientist V. I. Vernadsky, who discovered and explained the connection between living and non-living nature through the biogenic flow of atoms and molecules in the implementation of their basic life functions.

Chemical elements combine to form forgave complex inorganic compounds, which, together with organic substances, are the molecular components of the molecular level of organization. Simple substances (oxygen, nitrogen, metals, etc.) are formed by chemically combined atoms of the same element, and complex substances (acids, salts, etc.) consist of atoms of various chemical elements.

From simple and complex inorganic substances in biological systems are formed intermediate compounds(for example, acetate, keto acids), which form simple organic substances, or small biomolecules. These are, first of all, four classes of molecules - fatty acids, monosaccharides, amino acids and nucleotides. they are called building blocks, since molecules of the next hierarchical sublevel are built from them. Simple structural biomolecules are combined with each other by various covalent bonds, forming macromolecules. They are such important classes as lipids, proteins, oligo- and polysaccharides and nucleic acids.

In biosystems, macromolecules can be combined through non-covalent interactions in supramolecular complexes. They are also called intermolecular complexes, or molecular ensembles, or complex biopolymers (for example, complex enzymes, complex proteins). At the highest, already cellular level of organization, supramolecular complexes are combined with the formation of cellular organelles.

So, the molecular level is characterized by a certain structural hierarchy of molecular organization: chemical elements - simple and complex inorganic compounds - intermediates - small organic molecules - macromolecules - supramolecular complexes.

Molecular level of life organization
The main components that determine the spatial (structural) orderliness	The main processes that determine the time (functional) orderliness
1. Elementary chemical constituents: Organogens; Macronutrients; Microelements; Ultramicroelements. 2. Molecular chemical constituents: Simple inorganic molecules (02 N2, metals) Complex inorganic molecules (water, salts, acids, alkalis, oxides, etc.), Small organic molecules (fatty acids, amino acids, monosaccharides, nucleotides) Macromolecules (lipids, proteins, oligo- and polysaccharides, nucleic acids) supramolecular complexes.	1. Processes of transformation of substances. 2. Energy conversion processes. 3. Processes of transformation of hereditary information

Functional organization at the molecular level . The molecular level of organization of living nature also combines a huge number of different chemical reactions that determine its orderliness in time. Chemical reactions are phenomena in which some substances having a certain composition and properties are converted into other substances. - with a different composition and other properties. reactions between elements, inorganic substances are not specific to living things, specific to life there is a certain order of these reactions, their sequence and combination into an integral system. There are various classifications of chemical reactions. On the basis of changes in the amount of initial and final substances, 4 types of reactions are distinguished: messages, expansions, exchange and substitution. Depending on the use of energy, they emit exothermic(energy is released) and endothermic(energy is absorbed). Organic compounds are also capable of various chemical transformations, which can take place both without changes in the carbon skeleton, and with changes. Reactions without changing the carbon skeleton are substitution, addition, elimination, isomerization reactions. To reactions with a change in the carbon skeleton include reactions such as chain extension, chain shortening, chain isomerization, chain cyclization, ring opening, ring contraction, and ring expansion. The vast majority of reactions in biosystems are enzymatic and form an aggregate called metabolism. The main types of enzymatic reactions redox, transfer, hydrolysis, non-hydrolytic decomposition, isomerization and synthesis. In biological systems, reactions of polymerization, condensation, matrix synthesis, hydrolysis, biological catalysis, etc. can also occur between organic molecules. Most reactions between organic compounds are specific for living nature and cannot occur in inanimate.

Sciences that study the molecular level. The main sciences that study the molecular level are biochemistry and molecular biology. Biochemistry is the science of the essence of life phenomena and their basis is metabolism, and the attention of molecular biology, unlike biochemistry, is focused mainly on the study of the structure and functions of proteins.

Biochemistry - a science that studies the chemical composition of organisms, the structure, properties, significance of the chemical compounds found in them and their transformation in the process of metabolism. The term "biochemistry" was first proposed in 1882, however, it is believed that it gained wide use after the work of the German chemist K. Neuberg in 1903. Biochemistry as an independent science was formed in the second half of the 19th century. thanks to the scientific activity of such famous biochemists as A. M. Butlerov, F. Wehler, F. Misher, A. Ya. Danilevsky, Yu. Liebig, L. Pasteur, E. Buchner, K. A. Timiryazev, M. I. Lunin and others. Modern biochemistry, together with molecular biology, bioorganic chemistry, biophysics, microbiology, constitute a single complex of interrelated sciences - physical and chemical biology, which studies the physical and chemical foundations of living matter. One of the general tasks of biochemistry is to establish the mechanisms of functioning of biosystems and the regulation of cell vital activity, which ensure the unity of metabolism and energy in the body.

Molecular biology - a science that studies biological processes at the level of nucleic acids and proteins and their supramolecular structures. The date of the emergence of molecular biology as an independent science is considered to be 1953, when F. Crick and J. Watson, based on biochemistry and X-ray diffraction data, proposed a model of the three-dimensional structure of DNA, which was called the double helix. The most important sections of this science are molecular genetics, molecular virology, enzymology, bioenergetics, molecular immunology, and molecular developmental biology. The fundamental tasks of molecular biology are the establishment of the molecular mechanisms of the main biological processes due to the structural and functional properties and the interaction of nucleic acids and proteins, as well as the study of the regulatory mechanisms of these processes.

Methods for studying life at the molecular level were formed mainly in the 20th century. The most common of these are chromatography, ultracentrifugation, electrophoresis, X-ray diffraction analysis, photometry, spectral analysis, tracer method and etc.

All wildlife is a collection of biological systems of different levels of organization and different subordination.
The level of organization of living matter is understood as the functional place that a given biological structure occupies in the general system of organization of nature.

The level of organization of living matter is a set of quantitative and qualitative parameters of a certain biological system (cell, organism, population, etc.), which determine the conditions and boundaries of its existence.

There are several levels of organization of living systems, which reflect the subordination, hierarchy of the structural organization of life.

• Molecular (molecular-genetic) level represented by individual biopolymers (DNA, RNA, proteins, lipids, carbohydrates and other compounds); at this level of life, phenomena associated with changes (mutations) and the reproduction of genetic material, metabolism are studied. This is the science of molecular biology.
• Cellularlevel- the level at which life exists in the form of a cell - the structural and functional unit of life, is studied by cytology. At this level, processes such as metabolism and energy, information exchange, reproduction, photosynthesis, transmission of nerve impulses, and many others are studied.

The cell is the structural unit of all living things.

• tissue level studying histology.

Tissue is a combination of intercellular substance and cells similar in structure, origin and functions.

• Organlevel. An organ contains several tissues.
• Organismiclevel- the independent existence of an individual - a unicellular or multicellular organism is studied, for example, by physiology and autecology (ecology of individuals). An individual as an integral organism is an elementary unit of life. Life in nature does not exist in any other form.

An organism is a real carrier of life, characterized by all its properties.

• population-specieslevel- level, which is represented by a group of individuals of the same species - population; it is in the population that elementary evolutionary processes (accumulation, manifestation, and selection of mutations) take place. This level of organization is studied by such sciences as de-ecology (or population ecology), evolutionary doctrine.

A population is a collection of individuals of the same species that exist for a long time in a certain area, interbreed freely and are relatively isolated from other individuals of the same species.

• Biogeocenoticlevel- represented by communities (ecosystems) consisting of different populations and their habitats. This level of organization is studied by biocenology or synecology (community ecology).

Biogeocenosis is a combination of all species with varying complexity of organization and all factors of their habitat.

• biosphericlevel- level representing the totality of all biogeocenoses. In the biosphere, the circulation of substances and the transformation of energy with the participation of organisms take place.

The levels of organization of the organic world are discrete states of biological systems, characterized by subordination, interconnectedness, and specific patterns.

Structural levels of life organization are extremely diverse, but the main ones are molecular, cellular, ontogenetic, population-species, biocenotic and biospheric.

1. Molecular genetic standard of living. The most important tasks of biology at this stage is the study of the mechanisms of transmission of gene information, heredity and variability.

There are several mechanisms of variability at the molecular level. The most important of them is the mechanism of gene mutation - the direct transformation of the genes themselves under the influence of external factors. The factors causing the mutation are: radiation, toxic chemical compounds, viruses.

Another mechanism of variability is gene recombination. Such a process takes place during sexual reproduction in higher organisms. In this case, there is no change in the total amount of genetic information.

Another mechanism of variability was discovered only in the 1950s. This is a non-classical recombination of genes, in which there is a general increase in the amount of genetic information due to the inclusion of new genetic elements in the cell genome. Most often, these elements are introduced into the cell by viruses.

2. Cellular level. Today, science has reliably established that the smallest independent unit of the structure, functioning and development of a living organism is a cell, which is an elementary biological system capable of self-renewal, self-reproduction and development. Cytology is a science that studies a living cell, its structure, functioning as an elementary living system, explores the functions of individual cellular components, the process of cell reproduction, adaptation to environmental conditions, etc. Cytology also studies the features of specialized cells, the formation of their special functions and the development of specific cellular structures . Thus, modern cytology has been called cell physiology.

A significant advance in the study of cells occurred at the beginning of the 19th century, when the cell nucleus was discovered and described. Based on these studies, the cellular theory was created, which became the greatest event in biology in the 19th century. It was this theory that served as the foundation for the development of embryology, physiology, and the theory of evolution.

The most important part of all cells is the nucleus, which stores and reproduces genetic information, regulates the metabolic processes in the cell.

All cells are divided into two groups:

Prokaryotes - cells lacking a nucleus

eukaryotes are cells that contain nuclei

Studying a living cell, scientists drew attention to the existence of two main types of its nutrition, which allowed all organisms to be divided into two types:

Autotrophic - produce their own nutrients

· Heterotrophic - can not do without organic food.

Later, such important factors as the ability of organisms to synthesize the necessary substances (vitamins, hormones), provide themselves with energy, dependence on the ecological environment, etc. were clarified. Thus, the complex and differentiated nature of the relationships indicates the need for a systematic approach to the study of life at the ontogenetic level. .

3. Ontogenetic level. multicellular organisms. This level arose as a result of the formation of living organisms. The basic unit of life is an individual, and the elementary phenomenon is ontogenesis. Physiology deals with the study of the functioning and development of multicellular living organisms. This science considers the mechanisms of action of various functions of a living organism, their relationship with each other, regulation and adaptation to the external environment, origin and formation in the process of evolution and individual development of an individual. In fact, this is the process of ontogenesis - the development of the organism from birth to death. In this case, growth, movement of individual structures, differentiation and complication of the organism occur.

All multicellular organisms are composed of organs and tissues. Tissues are a group of physically connected cells and intercellular substances to perform certain functions. Their study is the subject of histology.

Organs are relatively large functional units that combine various tissues into certain physiological complexes. In turn, organs are part of larger units - body systems. Among them are the nervous, digestive, cardiovascular, respiratory and other systems. Only animals have internal organs.

4. Population-biocenotic level. This is a supra-organismal level of life, the basic unit of which is the population. In contrast to a population, 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. A species exists only through populations representing genetically open systems. Population biology is the study of populations.

The term "population" was introduced by one of the founders of genetics, V. Johansen, who called it a genetically heterogeneous set of organisms. Later, the population began to be considered an integral system, continuously interacting with the environment. It is the populations that are the real systems through which the species of living organisms exist.

Populations are genetically open systems, since the isolation of populations is not absolute and the exchange of genetic information is not possible from time to time. It is populations that act as elementary units of evolution; changes in their gene pool lead to the emergence of new species.

Populations capable of independent existence and transformation are united in the aggregate of the next supraorganismal level - biocenoses. Biocenosis - a set of populations living in a certain area.

The biocenosis is a system closed to foreign populations, for its constituent populations it is an open system.

5. Biogeocetonic level. Biogeocenosis is a stable system that can exist for a long time. Equilibrium in a living system is dynamic, i.e. represents a constant movement around a certain point of stability. For its stable functioning, it is necessary to have feedback between its control and executing subsystems. This way of maintaining a dynamic balance between various elements of biogeocenosis, caused by the mass reproduction of some species and the reduction or disappearance of others, leading to a change in the quality of the environment, is called an ecological disaster.

Biogeocenosis is an integral self-regulating system in which several types of subsystems are distinguished. Primary systems are producers that directly process inanimate matter; consumers - a secondary level at which matter and energy are obtained through the use of producers; then come second-order consumers. There are also scavengers and decomposers.

The cycle of substances passes through these levels in the biogeocenosis: life is involved in the use, processing and restoration of various structures. In biogeocenosis - a unidirectional energy flow. This makes it an open system, continuously connected with neighboring biogeocenoses.

Self-regulation of biogeocens proceeds the more successfully, the more diverse the number of its constituent elements. The stability of biogeocenoses also depends on the diversity of its components. The loss of one or more components can lead to an irreversible imbalance and its death as an integral system.

6. Biosphere level. This is the highest level of life organization, covering all the phenomena of life on our planet. The biosphere is the living substance of the planet and the environment transformed by it. Biological metabolism is a factor that unites all other levels of life organization into one biosphere. At this level, there is a circulation of substances and the transformation of energy associated with the vital activity of all living organisms living on Earth. Thus, the biosphere is a single ecological system. The study of the functioning of this system, its structure and functions is the most important task of biology at this level of life. Ecology, biocenology and biogeochemistry are engaged in the study of these problems.

The development of the doctrine of the biosphere is inextricably linked with the name of the outstanding Russian scientist V.I. Vernadsky. It was he who managed to prove the connection of the organic world of our planet, acting as a single inseparable whole, with geological processes on Earth. Vernadsky discovered and studied the biogeochemical functions of living matter.

Thanks to the biogenic migration of atoms, living matter performs its geochemical functions. Modern science identifies five geochemical functions that living matter performs.

1. The concentration function is expressed in the accumulation of certain chemical elements inside living organisms due to their activity. The result of this was the emergence of mineral reserves.

2. The transport function is closely related to the first function, since living organisms carry the chemical elements they need, which then accumulate in their habitats.

3. The energy function provides energy flows penetrating the biosphere, which makes it possible to carry out all the biogeochemical functions of living matter.

4. Destructive function - the function of destruction and processing of organic remains, during this process, the substances accumulated by organisms are returned to natural cycles, there is a cycle of substances in nature.

5. Average-forming function - transformation of the environment under the influence of living matter. The entire modern appearance of the Earth - the composition of the atmosphere, hydrosphere, upper layer of the lithosphere; most of the minerals; climate is the result of the action of Life.

The process of "translation" of hereditary information occurs at the level of life organization

1) cellular

2) organismic

3) biogeocenotic

4) molecular

Explanation.

Events at the cellular level provide bioinformational and material-energetic support for the phenomenon of life at all levels of its organization. Today, science has reliably established that the smallest independent unit of the structure, functioning and development of a living organism is a cell, which is an elementary biological system capable of self-renewal, self-reproduction and development. Biological (genetic, hereditary) information - DNA, the matrix mechanism of DNA replication and protein synthesis.

The translation process is the process of protein synthesis from amino acids on the mRNA (mRNA) template, carried out by the ribosome. Several components of the cell are involved, so the answer is at the cellular level of organization.

Answer: 1

Section: Fundamentals of Cytology

Guest 26.05.2014 18:14

Hello. Does the process of translation of hereditary information occur at the cellular level? I think it's molecular. There was a similar question a little higher and the molecular level of organization was indicated there.

Natalya Evgenievna Bashtannik

At the molecular genetic level, the most important processes of vital activity take place - coding, transmission and implementation of hereditary information. At the same level of organization of life, the process of changing hereditary information is carried out.

On the organoid cellular level, the most important processes of vital activity take place: metabolism (including protein biosynthesis - TRANSLATION) and the conversion of energy in the cell, its growth, development and division.

Guest 23.03.2015 19:21

At the molecular level, such processes occur as: the transfer of genetic information - replication, transcription, translation.

At the cellular level, there are processes such as: cellular metabolism, life cycles and division, which are regulated by enzyme proteins.

(Information based on the "Collection of multi-level tasks for preparing for the exam". The author of the collection is A.A. Kirilenko)

Natalya Evgenievna Bashtannik

Molecular level. The basis of organization at this level is represented by 4 nitrogenous bases, 20 amino acids, several hundred thousand biochemical reactions, almost all of which are associated with the synthesis or decomposition of ATP, the universal energy component of living things.

Cellular level. The cell is the smallest unit of life. All living things are made up of cells. The main mechanisms of reproduction of life work precisely at the cellular level.

At the cellular level, there are two main processes necessary for the self-reproduction of life - mitosis - cell division with the preservation of the number of chromosomes and genes, and meiosis - reduction division necessary for the production of germ cells - gametes.