Levels of organization of living matter- hierarchically subordinate to the level of organization of biosystems, reflecting the levels of their complication. Most often, six main structural levels of life are distinguished: molecular, cellular, organismal, population-species, biogeocenotic and biospheric. Typically, each of these levels is a system of lower level subsystems and a subsystem of a higher level system.

It should be emphasized that the construction of a universal list of levels of biosystems is impossible. It is advisable to single out a separate level of organization if new properties appear on it that are absent in systems of a lower level. For example, the phenomenon of life occurs on cellular level, and potential immortality - on the population. In the study of various objects or various aspects of their functioning, different sets of levels of organization can be distinguished. For example, in unicellular organisms, the cellular and organism levels coincide. When studying the proliferation (reproduction) of cells at the multicellular level, it may be necessary to isolate individual tissue and organ levels, since specific mechanisms of regulation of the process under study may be characteristic of a tissue and an organ.

One of the conclusions from general theory systems is that biosystems of different levels can be similar in their essential properties, for example, the principles of regulation of parameters important for their existence

Molecular level of life organization

These are classes of organic compounds specific to living organisms (proteins, fats, carbohydrates, nucleic acids, etc.), their interaction with each other and with inorganic components, their role in the metabolism and energy in the body, storage and transmission of hereditary information. This level can be called the initial, deepest level of organization of the living. Every living organism is made up of molecules of organic substances-proteins, nucleic acids, carbohydrates, fats in the cells. The connection between the molecular level and the next cellular level is ensured by the fact that molecules are the material from which supramolecular cellular structures are created. Only by studying the molecular level can one understand how the processes of the origin and evolution of life on our planet proceeded, what are the molecular foundations of heredity and metabolic processes in the body. After all, it is at the molecular level that the transformation of all types of energy and metabolism in the cell takes place. The mechanisms of these processes are also universal for all living organisms.

Components

• Molecules of inorganic and organic compounds
• Molecular complexes of chemical compounds (membrane, etc.)

Core Processes

• Combining molecules into special complexes
• Implementation of physical chemical reactions in order
• DNA copying, coding and transmission of genetic information

• Biochemistry
• Biophysics
• Molecular biology
• Molecular genetics

Cellular level of life organization

Represented by free-living unicellular organisms and cells included in multicellular organisms.

Components

• Complexes of molecules of chemical compounds and cell organelles.

Core Processes

• biosynthesis, photosynthesis
• Regulation of chemical reactions
• cell division
• attraction chemical elements Earth and solar energy in the biosystem

Science leading research at this level

• Genetic Engineering
• Cytogenetics
• Cytology
• Embryology Geology

Tissue level of life organization

The tissue level is represented by tissues that unite cells of a certain structure, size, location, and similar functions. The tissues arose during historical development together with bagatoclitinism. In multicellular organisms, they are formed during ontogenesis as a result of cell differentiation. In animals, several types of tissues are distinguished (epithelial, connective, muscle, nervous, as well as blood and lymph). In plants, meristematic, protective, basic and leading tissues are distinguished. At this level, cell specialization occurs.

Scientific disciplines that carry out research at this level: histology.

Organ level of life organization

The organ level is represented by the organs of organisms. In the simplest, digestion, respiration, circulation of substances, excretion, movement and reproduction are carried out by various organelles. In more advanced organisms are organ systems. In plants and animals, organs are formed by different quantity fabrics. Vertebrates are characterized by cephalization protected by the concentration of the most important centers and sense organs in the head.

Organismal level of organization of life

Represented by unicellular and multicellular organisms of plants, animals, fungi and bacteria.

Components

• The cell is the main structural component of the body. Cells form tissues and organs of multicellular organisms

Core Processes

• Metabolism (metabolism)
• Irritability
• reproduction
• Ontogenesis
• Neuro-humoral regulation of vital processes
• homeostasis

Science leading research at this level

• Anatomy
• Biometrics
• Morphology
• Physiology
• Histology

Population-species level of life organization

Represented in nature by a huge variety of species and their populations.

Components

• Groups of related individuals united by a certain gene pool and specific interaction with environment

Core Processes

1. genetic identity
2. Interactions between individuals and populations
3. Accumulation of elementary evolutionary transformations
4. Implementation of microevolution and development of adaptation to a changing environment

• Speciation

1. Increasing biodiversity

Science leading research at this level

• Population genetics
• Evolution theory
• Ecology

Biogeocenotic level of life organization

Represented by the diversity of natural and cultural ecosystems in all living environments.

Components

• Populations of different species
• environmental factors
• Food webs, matter and energy flows

Core Processes

• Biochemical cycling of substances and the flow of energy that sustain life
• Movable balance between living organisms and abiotic environment (homeostasis)
• Providing living organisms with living conditions and resources (food and shelter)

Science leading research at this level

• biogeography
• Biogeocenology
• Ecology

Biospheric level of life organization

Presented above is the global form of organization of biosystems - the biosphere.

Components

• Biogeocenoses
• Anthropogenic impact

Core Processes

• Active interaction of living and non-living matter of the planet
• Biological cycle of matter and energy
• Active biogeochemical participation of man in all processes of the biosphere, its economic and ethnocultural activities

Science leading research at this level

• Ecology
  • global ecology
  • space ecology
  • social ecology

Organization levels organic world- discrete states of biological systems, characterized by subordination, interconnectedness, 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 genetic 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 the science that studies 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 cell 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 ecological environment and others. Thus, the complex and differentiated nature of the connections indicates the need for a systematic approach to the study of life at the ontogenetic level as well.

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. Internal organs is only found in animals.

4. Population-biocenotic level. This is a supra-organismal level of life, the basic unit of which is the population. Unlike a population, a species is a collection of individuals that are similar in structure and physiological properties having a common origin, able to interbreed freely 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. it highest level organization of life, 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.

There are such levels of organization of living matter - levels of biological organization: molecular, cellular, tissue, organ, organism, population-species and ecosystem.

Molecular level of organization- this is the level of functioning of biological macromolecules - biopolymers: nucleic acids, proteins, polysaccharides, lipids, steroids. From this level, the most important life processes begin: metabolism, energy conversion, transfer hereditary information. This level is studied: biochemistry, molecular genetics, molecular biology, genetics, biophysics.

Cellular level- this is the level of cells (cells of bacteria, cyanobacteria, unicellular animals and algae, unicellular fungi, cells of multicellular organisms). 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.

Tissue level of organization- This is the level at which the structure and functioning of tissues is studied. This level is studied by histology and histochemistry.

Organ level of organization- This is the level of organs of multicellular organisms. Anatomy, physiology, embryology study this level.

Organismal level of organization- this is the level of unicellular, colonial and multicellular organisms. The specificity of the organismic level lies in the fact that at this level the decoding and implementation of genetic information takes place, the formation of traits inherent in individuals of a given species. This level is studied by morphology (anatomy and embryology), physiology, genetics, paleontology.

Population-species level is the level of populations of individuals - populations and species. This level is studied by systematics, taxonomy, ecology, biogeography, population genetics. At this level, genetic and ecological features of populations, elementary evolutionary factors and their impact on the gene pool (microevolution), the problem of species conservation.

Ecosystem level of organization- this is the level of microecosystems, mesoecosystems, macroecosystems. At this level, types of nutrition are studied, types of relationships between organisms and populations in an ecosystem, population size, population dynamics, population density, ecosystem productivity, successions. This level studies ecology.

Allocate also biospheric level of organization living matter. The biosphere is a giant ecosystem that occupies part of the geographic envelope of the Earth. This is a mega ecosystem. In the biosphere, there is a cycle of substances and chemical elements, as well as the conversion of solar energy.

2. Fundamental properties of living matter

Metabolism (metabolism)

Metabolism (metabolism) is a set of chemical transformations occurring in living systems that ensure their vital activity, growth, reproduction, development, self-preservation, constant contact with the environment, the ability to adapt to it and its changes. In the process of metabolism, splitting and synthesis of molecules that make up cells occur; formation, destruction and renewal of cellular structures and intercellular substance. Metabolism is based on interrelated processes of assimilation (anabolism) and dissimilation (catabolism). Assimilation - the processes of synthesis of complex molecules from simple ones with the expenditure of energy stored during dissimilation (as well as the accumulation of energy during the deposition of synthesized substances in the reserve). Dissimilation - the processes of splitting (anaerobic or aerobic) of complex organic compounds, going with the release of energy necessary for the implementation of the vital activity of the organism. Unlike bodies of inanimate nature, exchange with the environment for living organisms is a condition for their existence. In this case, self-renewal occurs. Metabolic processes occurring inside the body are combined into metabolic cascades and cycles by chemical reactions, which are strictly ordered in time and space. The coordinated flow of a large number of reactions in a small volume is achieved by the ordered distribution of individual metabolic links in the cell (the principle of compartmentalization). Metabolic processes are regulated with the help of biocatalysts - special proteins-enzymes. Each enzyme has substrate specificity to catalyze the conversion of only one substrate. This specificity is based on a peculiar "recognition" of the substrate by the enzyme. Enzymatic catalysis differs from non-biological in its extremely high efficiency, as a result of which the rate of the corresponding reaction increases by 1010 - 1013 times. Each enzyme molecule is capable of performing from several thousand to several million operations per minute without being destroyed in the process of participating in reactions. Another characteristic difference between enzymes and non-biological catalysts is that enzymes are able to accelerate reactions under normal conditions (atmospheric pressure, body temperature, etc.). All living organisms can be divided into two groups - autotrophs and heterotrophs, differing in sources of energy and necessary substances for their life. Autotrophs - organisms that synthesize from inorganic substances organic compounds using the energy of sunlight (photosynthetics - green plants, algae, some bacteria) or the energy obtained from the oxidation of an inorganic substrate (chemosynthetics - sulfur, iron bacteria and some others), Autotrophic organisms are able to synthesize all cell components. The role of photosynthetic autotrophs in nature is decisive - being the primary producer of organic matter in the biosphere, they ensure the existence of all other organisms and the course of biogeochemical cycles in the circulation of substances on Earth. Heterotrophs (all animals, fungi, most bacteria, some chlorophyll-free plants) are organisms that need ready-made organic substances for their existence, which, acting as food, serve as both a source of energy and a necessary "building material". A characteristic feature of heterotrophs is the presence of amphibolism in them, i.e. process of formation of small organic molecules(monomers) formed during the digestion of food (the process of degradation of complex substrates). Such molecules - monomers are used to assemble their own complex organic compounds.

Self-reproduction (reproduction)

The ability to reproduce (reproduce their own kind, self-reproduction) refers to one of the fundamental properties of living organisms. Reproduction is necessary in order to ensure the continuity of the existence of species, because. the lifespan of an individual organism is limited. Reproduction more than compensates for the losses caused by the natural extinction of individuals, and thus maintains the preservation of the species in a number of generations of individuals. In the process of evolution of living organisms, the evolution of methods of reproduction took place. Therefore, in the numerous and diverse species of living organisms that currently exist, we find different forms of reproduction. Many types of organisms combine several methods of reproduction. It is necessary to distinguish two fundamentally different types of reproduction of organisms - asexual (primary and more ancient type of reproduction) and sexual. In the process of asexual reproduction, a new individual is formed from one or a group of cells (in multicellular) of the mother organism. In all forms of asexual reproduction, the offspring have a genotype (set of genes) identical to the maternal one. Consequently, all the offspring of one maternal organism turns out to be genetically homogeneous and the daughter individuals have the same set of traits. In sexual reproduction, a new individual develops from a zygote formed by the fusion of two specialized germ cells (fertilization process) produced by two parental organisms. The nucleus in the zygote contains a hybrid set of chromosomes, which is formed as a result of the union of sets of chromosomes of fused gamete nuclei. In the nucleus of the zygote, thus, a new combination of hereditary inclinations (genes) is created, brought in equally by both parents. And the daughter organism developing from the zygote will have a new combination of features. In other words, during sexual reproduction, the implementation of a combinative form of hereditary variability of organisms occurs, which ensures the adaptation of species to changing environmental conditions and is an essential factor in evolution. This is a significant advantage of sexual reproduction over asexual reproduction. The ability of living organisms to self-reproduce is based on the unique property of nucleic acids to reproduce and the phenomenon of matrix synthesis, which underlies the formation of nucleic acid molecules and proteins. Self-reproduction at the molecular level determines both the implementation of metabolism in cells and the self-reproduction of the cells themselves. Cell division (self-reproduction of cells) underlies the individual development of multicellular organisms and the reproduction of all organisms. The reproduction of organisms ensures the self-reproduction of all species inhabiting the Earth, which in turn determines the existence of biogeocenoses and the biosphere.

Heredity and variability

Heredity provides material continuity (the flow of genetic information) between generations of organisms. It is closely related to reproduction at the molecular, subcellular and cellular levels. Genetic information that determines the diversity of hereditary traits is encrypted in the molecular structure of DNA (for some viruses, in RNA). The genes encode information about the structure of synthesized proteins, enzymatic and structural. The genetic code is a system of "recording" information about the sequence of amino acids in synthesized proteins using the sequence of nucleotides in the DNA molecule. The totality of all the genes of an organism is called the genotype, and the totality of traits is called the phenotype. The phenotype depends on both the genotype and the factors of the internal and external environment that affect the activity of genes and determine regular processes. The storage and transmission of hereditary information is carried out in all organisms with the help of nucleic acids, the genetic code is the same for all living beings on Earth, i.e. it is universal. Due to heredity, traits are transmitted from generation to generation that ensure the adaptability of organisms to their environment. If during the reproduction of organisms only the continuity of existing signs and properties was manifested, then against the background of changing environmental conditions, the existence of organisms would be impossible, since a necessary condition for the life of organisms is their adaptability to environmental conditions. Variability is manifested in the diversity of organisms belonging to the same species. Variability can be realized in individual organisms in the course of their individual development or within a group of organisms in a series of generations during reproduction. There are two main forms of variability, differing in the mechanisms of occurrence, the nature of the change in characteristics and, finally, their significance for the existence of living organisms - genotypic (hereditary) and modification (non-hereditary). Genotypic variability is associated with a change in the genotype and leads to a change in the phenotype. The basis of genotypic variability may be mutations (mutational variability) or new combinations of genes that occur during fertilization during sexual reproduction. In the mutational form, the changes are associated primarily with errors in the replication of nucleic acids. Thus, the emergence of new genes that carry new genetic information; new signs appear. And if the newly emerging signs are useful to the organism in specific conditions, then they are "caught up" and "fixed" by natural selection. Thus, the adaptability of organisms to environmental conditions, the diversity of organisms are based on hereditary (genotypic) variability, and the prerequisites for positive evolution are created. With non-hereditary (modification) variability, changes in the phenotype occur under the influence of environmental factors and are not associated with a change in the genotype. Modifications (changes in traits with modification variability) occur within the normal range of the reaction, which is under the control of the genotype. Modifications are not passed on to future generations. The value of modification variability lies in the fact that it ensures the adaptability of the organism to environmental factors during its life.

Individual development of organisms

All living organisms are characterized by the process of individual development - ontogenesis. Traditionally, ontogenesis is understood as the process of individual development of a multicellular organism (formed as a result of sexual reproduction) from the moment of formation of a zygote to the natural death of an individual. Due to the division of the zygote and subsequent generations of cells, a multicellular organism is formed, consisting of a huge number of different types of cells, various tissues and organs. The development of an organism is based on the "genetic program" (embodied in the genes of the chromosomes of the zygote) and is carried out in specific environmental conditions that significantly affect the process of implementing genetic information during the individual existence of an individual. On the early stages individual development, intensive growth occurs (increase in mass and size), due to the reproduction of molecules, cells and other structures, and differentiation, i.e. appearance of differences in structure and complication of functions. At all stages of ontogenesis, various environmental factors (temperature, gravity, pressure, food composition in terms of the content of chemical elements and vitamins, various physical and chemical agents) have a significant regulatory influence on the development of the organism. The study of the role of these factors in the process of individual development of animals and humans is of great practical importance, which increases with the intensification of anthropogenic impact on nature. In various fields of biology, medicine, veterinary medicine and other sciences, research is being widely carried out to study the processes of normal and pathological development of organisms, to elucidate the patterns of ontogenesis.

Irritability

An integral property of organisms and all living systems is irritability - the ability to perceive external or internal stimuli (impact) and adequately respond to them. In organisms, irritability is accompanied by a complex of changes, expressed in shifts in metabolism, electrical potential on cell membranes, physicochemical parameters in the cytoplasm of cells, in motor reactions, and highly organized animals are characterized by changes in their behavior.

4. central dogma molecular biology - a rule generalizing the implementation of genetic information observed in nature: information is transmitted from nucleic acids to squirrel but not in the opposite direction. The rule was formulated Francis Crick in 1958 year and brought into line with the data accumulated by that time in 1970 year. Transfer of genetic information from DNA to RNA and from RNA to squirrel is universal for all cellular organisms without exception; it underlies the biosynthesis of macromolecules. Genome replication corresponds to the DNA → DNA informational transition. In nature, there are also transitions RNA → RNA and RNA → DNA (for example, in some viruses), as well as a change conformations proteins transferred from molecule to molecule.

Universal ways of transferring biological information

In living organisms, there are three types of heterogeneous, that is, consisting of different polymer monomers - DNA, RNA and protein. The transfer of information between them can be carried out in 3 x 3 = 9 ways. The central dogma divides these 9 types of information transfer into three groups:

General - found in most living organisms;

Special - occurring as an exception, in viruses and at mobile elements of the genome or under biological conditions experiment;

Unknown - not found.

DNA replication (DNA → DNA)

DNA is the main way information is transmitted between generations of living organisms, so the exact duplication (replication) of DNA is very important. Replication is carried out by a complex of proteins that unwind chromatin, then a double helix. After that, DNA polymerase and its associated proteins build an identical copy on each of the two strands.

Transcription (DNA → RNA)

Transcription is a biological process, as a result of which the information contained in a DNA segment is copied onto a synthesized molecule. messenger RNA. Transcription is carried out transcription factors and RNA polymerase. AT eukaryotic cell the primary transcript (pre-mRNA) is often edited. This process is called splicing.

Translation (RNA → protein)

Mature mRNA is read ribosomes during the translation process. AT prokaryotic In cells, the process of transcription and translation is not spatially separated, and these processes are conjugated. AT eukaryotic transcription site in cells cell nucleus separated from the broadcast site ( cytoplasm) nuclear membrane, so mRNA transported from the nucleus into the cytoplasm. mRNA is read by the ribosome in the form of three nucleotide"words". complexes initiation factors and elongation factors deliver aminoacylated transfer RNAs to the mRNA-ribosome complex.

5. reverse transcription is the process of forming a double-stranded DNA on a single-stranded matrix RNA. This process is called reverse transcription, since the transfer of genetic information in this case occurs in the “reverse” direction relative to transcription.

The idea of ​​reverse transcription was initially very unpopular, as it contradicted central dogma of molecular biology, which suggested that DNA transcribed to RNA and beyond broadcast into proteins. Found in retroviruses, for example, HIV and in case retrotransposons.

transduction(from lat. transductio- movement) - transfer process bacterial DNA from one cell to another bacteriophage. General transduction is used in bacterial genetics to genome mapping and design strains. Both temperate and virulent phages are capable of transduction, the latter, however, destroy the bacterial population, so transduction with their help does not have of great importance either in nature or in research.

A vector DNA molecule is a DNA molecule that acts as a carrier. The carrier molecule must have a number of features:

Ability to autonomously replicate in a host cell (usually bacterial or yeast)

The presence of a selectable marker

Availability of convenient restriction sites

The most common vectors are bacterial plasmids.

Biosphere and man, the structure of the biosphere.

Biosphere - the shell of the Earth, inhabited by living organisms, under their influence and occupied by the products of their vital activity; "film of life"; global ecosystem of the Earth.

The boundaries of the biosphere:

Upper boundary in the atmosphere: 15-20 km. It is defined ozone layer, delaying short-wave ultraviolet radiation, detrimental to living organisms.

· Lower boundary in the lithosphere: 3.5-7.5 km. It is determined by the temperature of the transition of water into steam and the temperature of protein denaturation, however, in general, the spread of living organisms is limited to a depth of several meters.

· The boundary between the atmosphere and the lithosphere in the hydrosphere: 10-11 km. Determined by the bottom of the World Ocean, including bottom sediments.

Man is also a part of the biosphere, his activity surpasses many natural processes. This constant relationship is called the boomerang law, or the law feedback human-biosphere interaction.

In order to correct human behavior in relation to nature, B. Commoner formulated four laws, which, from the point of view of Reimers

1 - everything is connected to everything

2 - everything has to go somewhere

3 - nature knows best

4 - nothing is given for free

Structure of the biosphere:

· Living matter - the totality of the bodies of living organisms inhabiting the Earth is physico-chemically unified, regardless of their systematic affiliation. The mass of living matter is relatively small and is estimated at 2.4 ... 3.6 1012 tons (in dry weight) and is less than one millionth of the entire biosphere (about 3 1018 tons), which, in turn, is less than one thousandth of the mass of the Earth. But it is one of "the most powerful geochemical forces on our planet" because living organisms do not just inhabit the earth's crust but transform the face of the earth. Living organisms inhabit earth's surface very uneven. Their distribution depends on geographic latitude.

Biogenic substance - a substance created and processed by a living organism. Throughout organic evolution, living organisms have passed through their organs, tissues, cells, and blood a thousand times over most of the atmosphere, the entire volume of the world's oceans, and a huge mass of mineral substances. This geological role of living matter can be imagined from the deposits of coal, oil, carbonate rocks, etc.

Inert substance - products formed without the participation of living organisms.

· Bioinert substance - a substance that is created simultaneously by living organisms and inert processes, representing dynamically balanced systems of both. Such are soil, silt, weathering crust, etc. Organisms play a leading role in them.

Substance undergoing radioactive decay.

· Scattered atoms, continuously created from any kind of terrestrial matter under the influence of cosmic radiation.

A substance of cosmic origin.

levels of organization of life.

Levels of life organization - hierarchically subordinate levels of organization of biosystems, reflecting the levels of their complexity. Most often, seven basic structural levels of life are distinguished: molecular, cellular, organ-tissue, organism, population-species, biogeocenotic and biospheric. Typically, each of these levels is a system of lower level subsystems and a subsystem of a higher level system.

1) Molecular level organization of life

It is represented by a variety of molecules found in a living cell (Combining molecules into special complexes, encoding and transferring genetic information)

2) Tissue level of life organization

The tissue level is represented by tissues that unite cells of a certain structure, size, location and similar functions. Tissues arose in the course of historical development along with multicellularity .. In animals, several types of tissues (epithelial, connective, muscle, nervous) are distinguished. In plants, meristematic, protective, basic and conductive tissues are distinguished. At this level, cell specialization occurs.

3) Organ level of life organization

The organ level is represented by the organs of organisms. In protozoa, digestion, respiration, circulation of substances, excretion, movement and reproduction are carried out by various organelles. More advanced organisms have organ systems. In plants and animals, organs are formed due to a different number of tissues.

4) Organismic (ontogenetic) level of life organization

It is represented by unicellular and multicellular organisms of plants, animals, fungi and bacteria. A cell is the main structural component of an organism.

5) Population-species level of life organization

It is represented in nature by a huge variety of species and their populations.

6) Biogeocenotic level of life organization

It is represented by a variety of natural and cultural biogeocenoses in all living environments.

7) Biospheric level of life organization

It is represented by the highest, global form of organization of biosystems - the biosphere.

3. The prevalence and role of living matter on the planet.

Living organisms, regulate the circulation of substances, serve as a powerful geological factor that forms the surface of the Earth.

LEVELS OF LIVING ORGANIZATION

There are molecular, cellular, tissue, organ, organism, population, species, biocenotic and global (biospheric) levels of organization of the living. At all these levels, all the properties characteristic of living things are manifested. Each of these levels is characterized by features inherent in other levels, but each level has its own specific features.

Molecular level. This level is deep in the organization of the living and is represented by molecules of nucleic acids, proteins, carbohydrates, lipids and steroids that are in cells and are called biological molecules. At this level, the most important processes of vital activity (coding and transmission of hereditary information, respiration, metabolism and energy metabolism, variability, etc.) are initiated and carried out. The physical and chemical specificity of this level lies in the fact that the composition of the living includes a large number of chemical elements, but the bulk of the living is represented by carbon, oxygen, hydrogen and nitrogen. Molecules are formed from a group of atoms, and complex chemical compounds are formed from the latter, differing in structure and function. Most of these compounds in cells are represented by nucleic acids and proteins, the macromolecules of which are polymers synthesized as a result of the formation of monomers and the combination of the latter in a certain order. In addition, the monomers of macromolecules within the same compound have the same chemical groups and are connected using chemical bonds between atoms, their nonspecific

ical parts (areas). All macromolecules are universal, as they are built according to the same plan, regardless of their species. Being universal, they are at the same time unique, because their structure is unique. For example, the composition of DNA nucleotides includes one nitrogenous base of the four known (adenine, guanine, cytosine or thymine), as a result of which any nucleotide is unique in its composition. The secondary structure of DNA molecules is also unique.

The biological specificity of the molecular level is determined by the functional specificity of biological molecules. For example, the specificity of nucleic acids lies in the fact that they encode the genetic information for protein synthesis. Moreover, these processes are carried out as a result of the same stages of metabolism. For example, the biosynthesis of nucleic acids, amino acids, and proteins follows a similar pattern in all organisms. Fatty acid oxidation, glycolysis, and other reactions are also universal.

The specificity of proteins is determined by the specific sequence of amino acids in their molecules. This sequence further determines the specific biological properties of proteins, since they are the main structural elements of cells, catalysts and regulators of reactions in cells. Carbohydrates and lipids serve as the most important sources of energy, while steroids are important for the regulation of a number of metabolic processes.

At the molecular level, energy is converted - radiant energy into chemical energy stored in carbohydrates and other chemical compounds, a chemical energy carbohydrates and other molecules - into biologically available energy, stored in the form of macroergic bonds of ATP. Finally, here the energy of macroergic phosphate bonds is converted into work - mechanical, electrical, chemical, osmotic. The mechanisms of all metabolic and energy processes are universal.

Biological molecules also provide continuity between molecules and the next level (cellular), since they are the material from which supramolecular structures are formed. The molecular level is the "arena" of chemical reactions that provide energy to the cellular level.

Cellular level. This level of organization of the living is represented by cells acting as independent organizations.

mov (bacteria, protozoa, etc.), as well as cells of multicellular organisms. The main specific feature of this level is that life begins from it. Being capable of life, growth and reproduction, cells are the main form of organization of living matter, the elementary units from which all living beings (prokaryotes and eukaryotes) are built. There are no fundamental differences in structure and function between plant and animal cells. Some differences relate only to the structure of their membranes and individual organelles. There are noticeable differences in structure between prokaryotic cells and eukaryotic cells, but in functional terms, these differences are leveled, because the “cell from cell” rule applies everywhere.

The specificity of the cellular level is determined by the specialization of cells, the existence of cells as specialized units of a multicellular organism. At the cellular level, there is a differentiation and ordering of vital processes in space and time, which is associated with the confinement of functions to different subcellular structures. For example, eukaryotic cells have significantly developed membrane systems (plasma membrane, cytoplasmic reticulum, lamellar complex) and cell organelles (nucleus, chromosomes, centrioles, mitochondria, plastids, lysosomes, ribosomes). Membrane structures are the "arena" of the most important life processes, and the two-layer structure of the membrane system significantly increases the area of ​​the "arena". In addition, membrane structures provide spatial separation of many biological molecules in cells, and their physical state allows for the constant diffuse movement of some of the molecules of proteins and phospholipids contained in them. Thus, membranes are a system whose components are in motion. They are characterized by various rearrangements, which determines the irritability of cells - the most important property of the living.

tissue level. This level is represented by tissues that combine cells of a certain structure, size, location and similar functions. Tissues arose in the course of historical development along with multicellularity. In multicellular organisms, they are formed during ontogenesis as a result of cell differentiation. In animals, several types of tissues are distinguished (epithelial, connective, muscle, blood, nervous and reproductive). The races

shadows distinguish meristematic, protective, basic and conductive tissues. At this level, cell specialization occurs.

Organ level. Represented by organs of organisms. In plants and animals, organs are formed due to a different number of tissues. In protozoa, digestion, respiration, circulation of substances, excretion, movement and reproduction are carried out by various organelles. More advanced organisms have organ systems. Vertebrates are characterized by cephalization, which consists in the concentration of the most important nerve centers and sensory organs in the head.

Organism level. This level is represented by the organisms themselves - unicellular and multicellular organisms of plant and animal nature. A specific feature of the organismic level is that at this level the decoding and implementation of genetic information, the creation of structural and functional features inherent in organisms of a given species take place.

species level. This level is determined by plant and animal species. Currently, there are about 500 thousand plant species and about 1.5 million animal species, whose representatives are characterized by a wide variety of habitats and occupy different ecological niches. A species is also a unit of classification of living beings.

population level. Plants and animals do not exist in isolation; they are united in populations that are characterized by a certain gene pool. Within the same species, there can be from one to many thousands of populations. Elementary evolutionary transformations are carried out in populations, a new adaptive form is being developed.

Biocenotic level. It is represented by biocenoses - communities of organisms of different species. In such communities, organisms of different species depend to some extent on each other. In the course of historical development, biogeocenoses (ecosystems) have developed, which are systems consisting of interdependent communities of organisms and abiotic environmental factors. Ecosystems are characterized by a fluid balance between organisms and abiotic factors. At that level, the material-energy cycles associated with the vital activity of organisms are carried out.

Global (biospheric) level. This level is the highest form of organization of the living (living systems). It is represented by the biosphere. At this level, all matter-energy cycles are united into a single giant biospheric cycle of substances and energy.

Between different levels organization of the living there is a dialectical unity. The living is organized according to the type of systemic organization, the basis of which is the hierarchy of systems. The transition from one level to another is associated with the preservation of the functional mechanisms operating at the previous levels, and is accompanied by the appearance of a structure and functions of new types, as well as an interaction characterized by new features, i.e., a new quality appears.