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 a 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 connected 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.
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Molecular level of life organization |
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The main components that determine the spatial (structural) orderliness |
The main processes that determine the time (functional) orderliness |
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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. Exist various classifications 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 of the 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 - science that studies chemical composition organisms, structure, properties, significance of 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.
Levels of organization of the living
In the organization of the living, molecular, cellular, tissue, organ, organism, population, species, biocenotic and global (biospheric) levels are mainly distinguished. 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 found in cells and, as already noted, called biological molecules.
The sizes of biological molecules are characterized by a rather significant variety, which is determined by the space they occupy in living matter. The smallest biological molecules are nucleotides, amino acids and sugars. On the contrary, protein molecules are characterized by much larger sizes. For example, the diameter of a human hemoglobin molecule is 6.5 nm.
Biological molecules are synthesized from low molecular weight precursors, which are carbon monoxide, water and atmospheric nitrogen, and which in the process of metabolism are converted through intermediate compounds of increasing molecular weight (building blocks) into biological macromolecules with a large molecular weight (Fig. 42). At this level, the most important processes of vital activity begin and are carried out (coding and transmission of hereditary information, respiration, metabolism and energy, variability, etc.).
The physicochemical specificity of this level lies in the fact that the composition of the living includes a large number of chemical elements, but the main elemental composition of living things is represented by carbon, oxygen, hydrogen, nitrogen. Molecules are formed from groups of atoms, and complex molecules are formed from the latter. chemical compounds that differ 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 compounds 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 the atoms of their nonspecific parts (sites).
All macromolecules are universal, because 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 and thymine), as a result of which any nucleotide or any sequence of nucleotides in DNA molecules is unique in its composition, just as the secondary structure of the DNA molecule is also unique. Most proteins contain 100-500 amino acids, but the sequences of amino acids in protein molecules are unique, which makes them unique.
Combining, macromolecules different types form supramolecular structures, examples of which are nucleoproteins, which are complexes of nucleic acids and proteins, lipoproteins (complexes of lipids and proteins), ribosomes (complexes of nucleic acids and proteins). In these structures, the complexes are bound non-covalently, but non-covalent binding is very specific. Biological macromolecules are characterized by continuous transformations, which are provided by chemical reactions catalyzed by enzymes. In these reactions, enzymes convert a substrate into a reaction product within an extremely short time, which can be a few milliseconds or even microseconds. For example, the unwinding time of a double-stranded DNA helix before its replication is only a few microseconds.
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. This property is not shared by other biological molecules.
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 various processes occurring in cells. Carbohydrates and lipids are the most important sources of energy, while steroids in the form of steroid hormones are important for the regulation of a number of metabolic processes.
The specificity of biological macromolecules is also determined by the fact that the processes of biosynthesis are carried out as a result of the same stages of metabolism. Moreover, the biosynthesis of nucleic acids, amino acids and proteins proceeds according to a similar pattern in all organisms, regardless of their species. Fatty acid oxidation, glycolysis, and other reactions are also universal. For example, glycolysis occurs in every living cell of all eukaryotic organisms and is carried out as a result of 10 consecutive enzymatic reactions, each of which is catalyzed by a specific enzyme. All aerobic eukaryotic organisms have molecular "machines" in their mitochondria, where the Krebs cycle and other reactions associated with the release of energy take place. At the molecular level, many mutations occur. These mutations change the sequence of nitrogenous bases in DNA molecules.
At the molecular level, radiant energy is fixed and this energy is converted into chemical energy stored in cells in carbohydrates and other chemical compounds, and the chemical energy of carbohydrates and other molecules into biologically available energy stored in the form of ATP macroenergy bonds. Finally, at this level, 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 the molecular 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 living things is represented by cells acting as independent organisms (bacteria, protozoa, and others), 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 basic form of organization of living matter, 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 cells of eukaryotic organisms, but in functional terms, these differences are leveled, because the “cell from cell” rule applies everywhere. Supramolecular structures at this level form membrane systems and cell organelles (nuclei, mitochondria, etc.).
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 ensure the separation of cells from the environment, as well as the spatial separation of many biological molecules in cells. The cell membrane has a highly selective permeability. Therefore, their physical condition allows the constant diffuse movement of some of the protein and phospholipid molecules they contain. In addition to general-purpose membranes, cells have internal membranes that limit cell organelles.
By regulating the exchange between the cell and the environment, membranes have receptors that perceive external stimuli. In particular, examples of the perception of external stimuli are the perception of light, the movement of bacteria to a food source, the response of target cells to hormones, such as insulin. Some of the membranes themselves simultaneously generate signals (chemical and electrical). "A remarkable feature of the membranes is that energy conversion occurs on them. In particular, photosynthesis occurs on the inner membranes of chloroplasts, while oxidative phosphorylation occurs on the inner membranes of the mitochondria.
Membrane components are in motion. Constructed mainly from proteins and lipids, various rearrangements are inherent in membranes, which determines the irritability of cells - the most important property alive.
tissue level represented by tissues that combine cells of a certain structure, size, location and similar functions. The tissues arose during 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, nervous, as well as blood and lymph). In plants, meristematic, protective, basic and conductive tissues are distinguished. At this level, cell specialization occurs.
Organ level. Represented by 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 by different quantity fabrics. Vertebrates are characterized by cephalization, which is protected by the concentration of the most important centers and sense 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 organismal level is that at this level the decoding and implementation of genetic information, the creation of structural and functional features inherent in organisms of this species. Organisms are unique in nature because their genetic material is unique, which determines their development, functions, and their relationship with the environment.
population level. Plants and animals do not exist in isolation; they are grouped together in a population. By creating a supraorganismal system, populations are characterized by a certain gene pool and a certain habitat. In populations, elementary evolutionary transformations also begin, and an adaptive form is developed.
species level. This level is determined by the species of plants, animals and microorganisms that exist in nature as living links. The population composition of the species is extremely diverse. One species can include from one to many thousands of populations, whose representatives are characterized by a wide variety of habitats and occupy different ecological niches. Species are the result of evolution and are characterized by turnover. Now existing species not similar to the species that existed in the past. A species is also a unit of classification of living beings.
Biocenotic level. It is represented by biocenoses - communities of organisms of different species. In such communities, organisms different types 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 dynamic (mobile) balance between organisms and abiotic factors. At this level, the material-energy cycles associated with the vital activity of organisms are carried out.
Biosphere (global) level. This level is the highest form 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 of organization of the living there is a dialectical unity, the living is organized according to the type of system 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., is associated with the emergence of a new quality.
Issues for discussion
1. What is the general methodological approach to understanding the essence of life? When did it arise and why?
2. Is it possible to define the essence of life? If yes, what is this definition and what is its scientific basis?
3. Is it possible to raise the question of the substratum of life?
4. Name the properties of the living. Indicate which of these properties are characteristic of non-living things and which are only for living things.
5. What is the importance for biology of the division of the living into levels of organization? Does such a subdivision have any practical value?
6. What common features characterized different levels organization of the living?
7. Why are nucleoproteins considered the substrate of life and under what conditions do they fulfill this role?
Literature
Faithful D. The emergence of life M.: Mir. 1969. 391 pages.
Oparin A.V. Matter, life, intellect. M.: Science. 1977. 204 pages
Pekhov A.P. Biology and scientific and technical progress. M: Knowledge. 1984. 64 pages.
Karcher S. J. Molecular Biology. Acad. Press. 1995. 273pp.
Murphy M. P., O "Neill L. A. (Eds.) What is Life? The Next Fifty Years. Cambridge University Press. 1995. 203 pp.
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, 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.
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 these 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 gene recombination, in which overall increase 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, their formation special functions and 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 systems approach to the study of life and 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 individuals. 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 fabrics 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 periodically it is not possible to exchange genetic information. 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 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. biospheric level. This is 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 mineral; climate is the result of the action of Life.
There are 8 of them in total. What underlies the division of wildlife into levels? The fact is that at each level there are certain properties. Each next level necessarily contains the previous one or all the previous ones. Let's look at each level in detail:
1. Molecular level of organization of living nature
Organic and inorganic substances
the processes of synthesis and decomposition of these substances,
release and absorption of energy
These are all chemical processes that occur within any living system. This level cannot be called "live" at 100%. It is rather a "chemical level" - therefore it is the very first, the lowest of all. But it was this level that formed the basis for the division of Wildlife into kingdoms - according to the spare nutrient: in plants - carbohydrates, in fungi - chitin, in animals - protein.
Biochemistry
· Molecular biology
· Molecular genetics
2. Cellular level of wildlife organization
Includes the molecular level of organization. At this level, "the smallest indivisible biological system - the cell" already appears. Your metabolism and energy. The internal organization of a cell is its organelles. Life processes - origin, growth, self-reproduction (division)
Sciences that study the cellular level of organization:
Cytology
(Genetics)
(Embryology)
The brackets indicate the sciences that study this level, but this is not the main object of study.
3. Tissue level of organization
Includes molecular and cellular levels. This level can be called "multicellular" - after all, tissue is a collection of cells with a similar structure and performing the same functions.
The science that studies the tissue level of organization - histology.
4. Organ level of life organization
In unicellular organisms, these are organelles - each has its own structure and functions.
In multicellular organisms, these are organs that are combined into systems and clearly interact with each other.
These two levels - tissue and organ - study the sciences:
Botany - plants,
zoology - animals,
Anatomy - human
Physiology
· (the medicine)
5. Organism level
Includes molecular, cellular, tissue and organ levels.
Already at this level wildlife divided into kingdoms - plants, fungi and animals.
Properties of this level:
Metabolism (and at the cellular level too - you see, each level contains the previous one!)
The structure of the body
· Nutrition
Homeostasis - the constancy of the internal environment
Reproduction
Interactions between organisms
Interaction with the environment
Anatomy
· Genetics
Morphology
Physiology
6. Population-species level of life organization
Includes molecular, cellular, tissue levels, organ and organism.
If several organisms are morphologically similar (in other words, have the same structure), and have the same genotype, then they form one species or population.
The main processes at this level are:
The interaction of organisms with each other (either competition or reproduction)
microevolution (change of an organism under the influence of external conditions)
Sciences studying this level:
· Genetics
Evolution
Ecology
7. Biogeocenotic level of life organization (from the word biogeocenosis)
At this level, almost everything is already taken into account:
Interaction of organisms with each other - food chains and webs
The interaction of organisms with each other - competition and reproduction
The influence of the environment on organisms and, accordingly, the influence of organisms on their habitat
The science that studies this level is Ecology.
8. Biospheric level of wildlife organization (the last level is the highest!)
It includes:
The interaction of living and non-living components of nature
Biogeocenoses
Human Influence - " anthropogenic factors"
Circulation of substances in nature
And studies all this - Ecology!
About the cell in the scientific world started talking almost immediately after the invention of the microscope.
By the way, now there are quite a few types of microscopes:
Optical microscope - maximum magnification - ~2000x (you can see some microorganisms, cells (plants and animals), crystals, etc.
Electron microscope- magnifies up to 106 times. It is already possible to study particles of both cells and molecules - this is already the level of microstructures
The first scientist who was able to see cells (of course, through a microscope) was Robert Hooke(1665) - he studied cellular structure mostly plants.
But for the first time he spoke about unicellular organisms - bacteria, ciliates A. Van Leeuwenhoek(1674)
La Mark(1809) already began to talk about the cell theory
Well, already in the middle of the 19th century, M. Schleiden and T. Schwann formulated the cellular theory, which is now generally recognized throughout the world.
All organisms are cellular except viruses
Cell- an elementary unit of the structure and life of all organisms, having its own metabolism, capable of independent existence, self-reproduction and development. All living organisms either, like multicellular animals, plants and fungi, consist of many cells, or, like many protozoa and bacteria, are single-celled organisms. The branch of biology that deals with the study of the structure and activity of cells is called cytology. Recently, it has also become customary to talk about cell biology, or cell biology.
Cell is a mini organism. She has her own "organs" - organoids. The main organoid of the cell is the nucleus. On this basis, all living organisms are divided into EUKARYOTIC ("karyo" - the nucleus) - containing a nucleus and PROKARYOTIC ("pro" - to) - pre-nuclear (without a nucleus)
Provisions of the cell theory of Schleiden-Schwann
1. All animals and plants are made up of cells.
2. Plants and animals grow and develop through the emergence of new cells.
3. A cell is the smallest unit of a living thing, and the whole organism is a collection of cells.
The main provisions of modern cell theory
A cell is a unit of structure, life activity, growth and development of living organisms; there is no life outside the cell.
· Cell - one system, consisting of many naturally interconnected elements, representing a certain integral formation.
The core is the main component cells (eukaryotes).
New cells are formed only as a result of the division of the original cells.
Cells of multicellular organisms form tissues, tissues form organs. The life of an organism as a whole is determined by the interaction of its constituent cells.
The main organoids of a cell are those components that are inherent in all cells of living organisms - " general composition":
nucleus: nucleolus; nuclear membrane;
The plasma membrane
· endoplasmic reticulum;
The centriole
The Golgi complex
the lysosome
vacuole
mitochondria.
Nucleic acids contained in the cell of absolutely any organism. Even for viruses.
"Nucleo" - "nucleus" - is mainly contained in the nucleus of cells, but is also contained in the cytoplasm and other organelles. There are two types of nucleic acids: DNA and RNA
DNA - deoxyribonucleic acid
RNA - ribonucleic acid
These molecules are polymers, monomers are nucleotides - compounds containing nitrogenous bases.
DNA nucleotides: A - adenine, T - thymine, C - cytosine, G - guanine
RNA nucleotides: A - adenine, U - uracil, C - cytosine, G - guanine
As you can see, there is no thymine in RNA, it is replaced by uracil -
In addition to them, the composition of nucleotides includes:
carbohydrates: deoxyribose - in DNA, ribose - in RNA. Phosphate and sugar - are part of both molecules
This is the basic structure of molecules.
The secondary structure is the very shape of the molecules. DNA is a double helix, RNA is a "single" long molecule.
Main Functions of Nucleic Acids
The genetic code is the sequence of nucleotides in the DNA molecule. This is the basis of any organism, in fact - this is information about the organism itself (like any person, the full name that identifies the person is a sequence of letters, or a sequence of numbers - a series of passports).
So here it is main functions of nucleic acids- in the storage, implementation and transmission of hereditary information, "recorded" in molecules in the form of a sequence of certain nucleotides.
Cell division is part of the life process of absolutely any living organism. All new cells are formed from old (mother) cells. This is one of the main provisions of the cell theory. But there are several types of division, which directly depend on the nature of these cells.
division of prokaryotic cells
How is a prokaryotic cell different from a eukaryotic cell? The most important difference is the absence of a core (which is why they are called so). The absence of a nucleus means that the DNA is simply in the cytoplasm.
The process looks like this:
replication (doubling) of DNA ---> the cell lengthens ---> is formed transverse partition---> cells separate and diverge
division of eukaryotic cells
The life of any cell consists of 3 stages: growth, preparation for division and, in fact, division.
How is the division prepared?
First, protein is synthesized
Secondly, all the important components of the cell are doubled so that each new cell has the entire set of organelles necessary for life.
Thirdly, the DNA molecule doubles and each chromosome synthesizes a copy for itself. Doubled chromosome = 2 chromatids (each with a DNA molecule).
This period of preparation for delusion is called INTERPHASE.