Continuation. See No. 11/2005

Biology lessons in science classes

Advanced planning, grade 10

2. Water's ability to adhesion. Its property of being attracted to any surface that carries an electrical charge allows it to rise through small pores in the soil and through xylem vessels in plants to great heights.

3. The adhesion forces between water molecules provide it viscosity Therefore, water is a lubricant in biological systems. For example, synovial fluid in vertebrate joints.

4. Water is good solvent ionic (polar), as well as some nonionic compounds, the molecules of which contain charged (polar) groups. Any polar compounds in water hydrated(surrounded by water molecules), while water molecules participate in the formation of the structure of molecules of organic substances. If the energy of attraction of water molecules to molecules of a substance is greater than the energy of attraction between the molecules of the substance itself, then the substance dissolves in water. In relation to water there are: hydrophilic substances(from Greek hydros– water and filleo- to love), highly soluble in water, and hydrophobic substances(from Greek hydros And Phobos- fear), practically insoluble in water.

Hydrophilic (A) and hydrophobic (B) molecules

In the molecules of hydrophilic substances, polar groups predominate (–OH; C=O; –COOH; –NH2), which are capable of establishing hydrogen bonds with water molecules. Salts, acids, alkalis, proteins, and carbohydrates have hydrophilic properties.

Hydrophobic substances have non-polar molecules that are repelled by water molecules. Fats, gasoline, polyethylene and other substances do not dissolve in water.

The property of water as a solvent is of great importance for living organisms, since most biochemical reactions can only occur in an aqueous solution. In addition, as a solvent, water ensures both the influx of substances into the cell and the removal of waste products from it.

5. Mobility water molecules is explained by the fact that the hydrogen bonds connecting neighboring molecules are weak, which leads to constant collisions of its molecules in the liquid phase. The molecular mobility of water allows osmosis(diffusion, the directed movement of molecules through a semi-permeable membrane into a more concentrated solution), necessary for the absorption and movement of water in living systems.

6. Among the most common liquids in nature, water has the highest heat capacity, so it has a high boiling point (100 °C) and a low freezing point (0 °C). Such properties of water allowed it to become the main component of intracellular and intraorganismal fluids. True, the freezing point of water is slightly higher than would be ideal for life, since vast areas on Earth have temperatures below 0 °C. If ice crystals form in a living organism, they can destroy its delicate internal structures and cause its death. Winter wheat, a number of insects, and frogs have natural antifreezes in their bodies that prevent the formation of ice in their cells.

7. "Unusual" density and “behavior” of water near freezing point lead to the fact that ice floats on the surface of reservoirs, creating an insulating layer that, at low temperatures, protects aquatic inhabitants and the reservoir from complete freezing.

8. Water has a high specific heat of vaporization, therefore, As water evaporates, it cools the body(when 1 g of water evaporates, the body loses 2430 J of energy). It is known that in a day of hard work a person loses up to 10 liters of sweat. If sweat were not released and evaporated during work, the body would “heat up” to 100 °C. The evaporation of water from the surface of plant leaves during transpiration also contributes to cooling.

9. Water is reagent In many chemical reactions. For example, hydrolytic breakdown of proteins, carbohydrates, fats, etc. Water plays the role of a source of oxygen released during photosynthesis and hydrogen, which is used to restore the products of carbon dioxide assimilation.

10. The high heat capacity and thermal conductivity of water contributes to uniform distribution of heat in the cell and in the body.

Thus, water is the most amazing liquid on Earth, the properties of which surpass all imagination. The unique properties of water allow it to perform equally unique biological functions.

III. Consolidation of knowledge

Filling out the table “Biological functions of water.”

Table 3. Biological functions of water

Properties of water

Biological significance

1. High boiling point 2. Freeze expansion 3. Good solvent 4. Combination of high heat capacity and high thermal conductivity 5. Capillarity 6. High latent heat of vaporization 7. Transparency 8. Almost complete incompressibility 9. Molecular mobility 10. Viscosity

Forms the basis of the internal environment of organisms Ice protects water bodies from freezing, and aquatic inhabitants of frozen lakes, ponds and rivers from death Most biochemical reactions occur in aqueous solutions Maintaining thermal balance of the body, ensuring its thermal stability The rise of water and substances dissolved in it to great heights in the soil and in the body of plants Cools the body with minimal water loss Possibility of photosynthesis at shallow depths Keeping organisms in shape Possibility of osmosis Lubricating properties

IV. Homework

Study the textbook paragraph (structure, properties and biological functions of water).

Lesson 4. Mineral salts and their biological role

Equipment: tables on general biology, diagrams of the structure of the water molecule and the formation of hydrogen bonds.

I. Test of knowledge

Working with cards

Card 1. Read an excerpt from M. Dudnik’s poem:

They say eighty percent
Man is made of water.
From the water, I might add, of his native rivers.
From the water - I will add - the rains that gave him something to drink.
From the water - I will add - from the ancient water of the springs,
From which both grandfathers and great-grandfathers drank it...

How do you understand this text from the point of view of knowledge about the composition of living matter and the role of water in living nature?

Card 2. If you grind a phenolphthalein tablet in a mortar and add a few alkali granules, then no reaction is observed between these substances - no coloring occurs. What needs to be done for the reaction to occur?

Card 3. A large vessel of water placed in the cellar protects vegetables from freezing. Why?

Card 4. On a clear spring day, the air temperature is 10 ° C, the relative humidity is 80%. Will there be frost at night? Why are tomato and cucumber seedlings watered abundantly before freezing?

Card 5. Why are alpine plants short? Why does all parts of these plants accumulate more sugar than similar plants located outside the alpine zone?

Card 6. On the driest and hottest days, bees “hang” droplets of water on the upper walls of the chambers in the hive. For what?

Card 7. As a result of evolution, a rich storehouse of chemical compounds has been created in living nature. It is known that the plant world is the richest in chemical compounds actively used by humans. How can we explain the abundance of chemicals in the plant world and not in the animal world? In what areas of the Earth can we expect the growth of plant communities richest in chemical compounds?

Card 8. Everyone knows that water striders run on water as if on dry land. Water can be poured into a glass with the top on and it will not spill, unlike other liquids. How do you explain this phenomenon? What property of water makes this possible?

1. Hydrogen bond and its role in the “chemistry” of life.

3. The structure of the water molecule. Formation of hydrogen bonds between water molecules.

4. Properties and functions of water in the cell and body ( two students).

II. Learning new material

The cell contains 1–1.5% mineral salts. Salts are ionic compounds, i.e. they contain atoms with partially acquired positive and negative charges. In water, salts easily dissolve and break down into ions, i.e. dissociate to form a metal cation and an acid residue anion. For example:

NaCl ––> Na + + Сl – ;

H 3 PO 4 ––> 2H + + HPO 4 2– ;

H 3 PO 4 ––> H + + H 2 PO 4 – .

Therefore, we say that salts are contained in the cell in the form of ions. Are represented to the greatest extent in the cell and have the greatest significance

cations: K +, Na +, Ca 2+, Mg 2+;

anions: HPO 4 2–, H 2 PO 4 –, Cl –, HCO 3 –, HSO 4 –.

Living tissues also contain salts that are in a solid state, for example, calcium phosphate, which is part of the intercellular substance of bone tissue and mollusk shells.

2. Biological significance of cations

Let us consider the importance of the most important cations in the life of the cell and organism.

1. Sodium and potassium cations (K + and Na +), the concentration of which in the cell and in the intercellular space varies greatly - the concentration of K + inside the cell is very high, and Na + is low. While the cell is alive, differences in the concentrations of these cations are firmly maintained. Due to the difference in the concentrations of sodium and potassium cations on both sides of the cell membrane, a potential difference is created and maintained on it. Also, thanks to these cations, it is possible to transmit excitation along nerve fibers.

2. Calcium cations (Ca 2+) are an activator of enzymes, promote blood clotting, are part of bones, shells, calcareous skeletons, and participate in the mechanisms of muscle contraction.

3. Magnesium cations (Mg 2+) are also enzyme activators and are part of chlorophyll molecules.

4. Iron cations (Fe 2+) are part of hemoglobin and other organic substances.

3. Biological significance of anions

Despite the fact that during the life of the cell acids and alkalis are continuously formed, normally the cell reaction is slightly alkaline, almost neutral (pH = 7.2). This is ensured by the anions of weak acids contained in it, which bind or release hydrogen ions, as a result of which the reaction of the cell environment remains virtually unchanged.

The ability of a cell to maintain a certain concentration of hydrogen ions (pH) is called buffering.

Inside the cell, buffering is provided mainly by H 2 PO 4 – anions. In the extracellular fluid and blood, the role of a buffer is played by CO 3 2– and HCO 3 –. The buffering capacity is partly ensured by cations that form slightly soluble bases - they bind hydroxyl ions (OH –) when they are in excess.

III. Consolidation of knowledge

Summarizing conversation while learning new material.

IV. Homework

Study the textbook paragraph (mineral salts, their biological role).

Using the text of the textbook, notes taken in class and additional sources of information, fill out the table. 4 (enter into the table information about the biological role of the following elements: Mg, Na, Ca, Fe, K, S, P, Cl, Zn, Cu, I, F, Mn, B, Mo, Co).

Lesson 5. Organic substances. Lipids - relationship between structure, properties and functions

Equipment: tables on general biology, diagrams of the structure of lipids and their classification.

I. Test of knowledge

Working with cards

Card 1. How do you think we can explain the similarity in salt composition of the plasma of terrestrial vertebrates and sea water?

Card 2. What can a change in the salt composition of blood plasma lead to?

Card 3. How does the lack of any necessary element in a cell and body affect their vital functions? How might this manifest itself? Give examples.

Card 4. Is the statement true: “Dihydrogen phosphate ions can lower the pH of the cell by turning into hydrogen phosphate ions”?

Card 5. Among the salts formed by a monovalent cation and a monovalent anion, there are much more soluble in water than among the salts formed by a divalent cation and a divalent anion. Why do you think?

Oral knowledge test on questions

2. Biological functions of cations.

3. Biological functions of anions.

Checking the completion of Table 4 (see Table 4a).

	Role in the cage	Role in the body
		vegetable	animal
Magnesium (Mg)	Cofdactor of many enzymes	Part of the chlorophyllide molecule; Mg 2+ ion forms salts with pectic substances	Contains enzymes necessary for the functioning of muscle, nerve and bone tissues
Sodium (Na)	Participates in the creation and maintenance of bioelectric potential on the cell membrane	The Na + ion is involved in maintaining the osmotic potential of cells, which ensures the absorption of water from the soil	Na + ions affect kidney function, are involved in maintaining heart rhythm, are part of blood minerals, and are involved in regulating acid-base balance in the body
	Part of oxidative enzymes involved in the synthesis of cytochromes	Part of enzymes involved in dark reactions of photosynthesis	Participates in the synthesis of hemoglobin; in invertebrates it is part of the respiratory pigment - hemocyanin; in humans it is part of an enzyme involved in the synthesis of melanin
Iron (Fe)	Part of cytochromes - enzymes - electron carriers in the light phase of photosynthesis and in the respiratory chain	Participates in the synthesis of chlorophyll, is part of enzymes involved in respiration, is part of cytochromes - electron carriers during photosynthesis	It is part of the non-protein part of hemoglobin - heme and the myoglobin protein, which contains the supply of oxygen in the muscles, and is found in small quantities in the liver and spleen in the form of ferritin protein
Calcium (Ca)	Ca 2+ ions are involved in the regulation of selective permeability of the cell membrane, in the processes of connecting DNA with proteins	Ca 2+ ions, forming salts of pectin substances, give hardness to the intercellular substance connecting plant cells	Insoluble calcium salts are found in the bones of vertebrates, mollusk shells, and coral polyps; Ca 2+ ions are involved in the formation of bile, in the transmission of nerve impulses through synapses, are one of the blood clotting factors, and activate enzymes during the contraction of striated muscle fibers
	Participates in the creation and maintenance of membrane potential, activates enzymes involved in protein synthesis, and is part of glycolytic enzymes	Participates in the regulation of water regime, is part of photosynthesis enzymes, a component of cell sap of vacuoles (contained in the form of K + cations)	Participates together with sodium and calcium in maintaining heart rhythm, participates in the conduction of nerve impulses
	Contains amino acids (cysteine, cystine, methionine); participates in the formation of the tertiary structure of proteins (disulfide bridges); is part of coenzyme A and some enzymes; participates in the process of photosynthesis in bacteria; sulfur compounds serve as an energy source for some chemosynthetics	Determined by role in the cell	Determined by role in the cell; part of insulin, vitamin B 1, biotin
Phosphorus (P)	In the form of orthophosphoric acid residues, it is part of ATP, nucleotides, DNA, RNA, coenzymes NAD +, NADP +, FAD +, phosphorylated sugars, phospholipids, and many enzymes; is part of all membrane structures	Determined by role in the cell	In the form of phosphates, it is part of bone tissue and tooth enamel; The phosphate buffer system of mammals maintains the pH of tissue fluid in the range of 6.9–7.4
	Cl anions – participate in maintaining the electroneutrality of the cell	Cl anions – participate in the regulation of turgor pressure	Cl anions, together with sodium cations, participate in the formation of the osmotic potential of blood plasma; participate in the processes of excitation and inhibition in nerve cells; are part of hydrochloric acid, which is a component of gastric juice
			In vertebrates, it is part of the thyroid hormone, thyroxine.
Manganese (Mn)	Part of enzymes involved in respiration, oxidation of fatty acids, increasing the activity of the enzyme carboxylase	Part of enzymes involved in dark reactions of photosynthesis and in the reduction of nitrates	Part of phosphatases - enzymes necessary for bone growth
	Part of the enzymes involved in alcoholic fermentation	Part of enzymes that activate the breakdown of carbonic acid and enzymes involved in the synthesis of plant hormones - auxins	Part of an enzyme involved in the transport of carbon dioxide in the blood of vertebrates; an enzyme that hydrolyzes peptide bonds during protein digestion; enzymes necessary for normal growth
			In the form of insoluble calcium salts it is part of bones and dental tissue.
		Affects growth processes. Deficiency leads to the death of apical buds, flowers, ovaries, and conductive tissues
Molybdenum (Mo)	Part of enzymes involved in nitrogen fixation in nitrifying bacteria	Part of enzymes that regulate the functioning of the stomatal apparatus and enzymes involved in the synthesis of amino acids	Determined by role in the cell
Cobalt (Co)			It is part of vitamin B 12 and takes part in the synthesis of hemoglobin. Deficiency leads to anemia

II. Learning new material

1. Organic substances of living matter

Water with salts dissolved in it is a necessary medium for the chemical processes that make up life. However, life itself is all kinds of transformations of many different large molecules, the main element of which is carbon.

Substances containing carbon atoms are called organic. Only the simplest carbon-containing compounds, such as carbon monoxide (IV) - CO 2 or carbonic acid salts (NaHCO 3; Na 2 CO 3), are considered inorganic. Inorganic substances also include all compounds that do not contain carbon, although many of them are present in the cell.

Carbon's unique role in the chemistry of life is related to the structure of its atoms. One carbon atom is capable of forming four covalent bonds, and a large number of such atoms can be combined into long chains. Sometimes the ends of the carbon chains join together to form ring structures.

Carbon atoms can form bonds with atoms of some other elements, usually H, O, N, S. Carbon chains and rings make up the “skeletons” of organic molecules.

Carbon is the only element capable of forming enough different complex and stable compounds to provide the diversity of molecules found in living things.

We already know that organic substances of living matter include carbohydrates, fats, nucleic acids, proteins, as well as ATP and other low-molecular organic compounds. Let's begin to characterize the role of organic substances in the “chemistry” of life with fats.

2. Lipid content in the cell and in the body

Lipids are a large group of natural organic substances. Their name comes from the Greek word lipos– fat, since they include fats (actually lipids) and fat-like substances (lipoids). Each cell of an animal or plant organism contains a very specific amount of lipids.

Animal fats are found in milk, meat, subcutaneous fiber, and in plants - in seeds, fruits and other organs. Vegetable fats are called oils.

Free fat can be roughly divided into two large groups: protoplasmic (constitutional) and reserve.

Protoplasmic fat is involved in the construction of every cell. It is part of membrane intracellular structures. The amount of protoplasmic fat is constant and practically does not change under any conditions of the body. For example, in humans, protoplasmic fat makes up about 25% of the total fat found in the body.

Unsaturated – stearic (a), palmitic (b) and saturated – oleic (c) fatty acids

Reserve fat is a very convenient form of energy storage. This is due to the fact that the calorie content of fat is almost twice as high as the calorie content of protein and carbohydrates. The amount of reserve fat may vary depending on various conditions (gender, age, activity patterns, diet, etc.). In humans, fat depots are subcutaneous tissue, omentum, perinephric capsule, etc.

The cells of the brain, sperm, and ovaries are rich in fat - their amount is 7.5–30%.

In addition to free fat, the body contains a large amount of fat associated with carbohydrates and proteins.

3. Structure and properties of lipids

Lipids are organic compounds with different structures but common properties. According to their chemical structure, fats are esters of trihydric alcohol glycerol and high molecular weight fatty acids.

R1, R2, R3 are fatty acid radicals. Of these, the most common are palmitic [CH3–(CH2)15–COOH], stearic [CH3–(CH2)16–COOH], and oleic fatty acids.

All fatty acids are divided into two groups: saturated, i.e. not containing double bonds, and unsaturated, or unsaturated, containing double bonds.

From the above formulas it is clear that saturated acids include palmitic and stearic acids, and unsaturated acids include oleic acid. The properties of fats are determined by the qualitative composition of fatty acids and their quantitative ratio. Vegetable fats are rich in unsaturated fatty acids; they are fusible - liquid at room temperature. Animal fats are solid at room temperature because they contain mainly saturated fatty acids.

From the formula of fat it is clear that its molecule, on the one hand, contains a glycerol residue - a substance highly soluble in water, and on the other - fatty acid residues, the non-polar hydrocarbon chains of which are practically insoluble in water (carbon and hydrogen atoms attract electrons with approximately equal force). Nonpolar chains of fatty acids therefore gravitate toward nonpolar organic substances (chloroform, ether, oil). Due to this feature, lipid molecules are located at the interface between water and non-polar organic compounds or between water and the air phase, oriented in such a way that their polar parts face the water.

This orientation of lipid molecules relative to water plays a very important role. The thinnest layer of these substances, which is part of cell membranes, prevents the contents of the cell or its individual parts from mixing with the environment.

Thus, lipids are small molecules with predominant hydrophobic properties.

4. Classification of lipids

There are different lipids found in living organisms. Based on their structural features, several groups of lipids are distinguished.

1. Simple lipids(fats, waxes). Their molecules consist of fatty acids combined with glycerol - fats or other monohydric alcohols - waxes. Waxes form a protective lubricant on the skin, fur and feathers, cover the leaves and fruits of higher plants, as well as the cuticle of the exoskeleton of many insects. These substances are very hydrophobic.

2. Complex lipids– consist of glycerol, fatty acids and other components. This group includes: phospholipids (derivatives of orthophosphoric acid, are part of all cell membranes); glycolipids (contain sugar residues, there are many of them in nervous tissue); lipoproteins (complexes of lipids with proteins).

3. - small hydrophobic molecules that are derivatives of cholesterol. These include many important hormones (sex hormones and hormones of the adrenal cortex), terpenes (essential oils on which the smell of plants depends), some pigments (chlorophyll, bilirubin), some vitamins (A, D, E, K), etc.

To be continued

· all living cells can only exist in a liquid environment

1. Water is a universal solvent (for polar molecules and non-polar compounds)

q According to the degree of solubility, substances are divided into:

Hydrophilic(highly soluble in water) - salts, mono- and disaccharides, simple alcohols, acids, alkalis, amino acids, peptides

· hydrophilicity is determined by the presence of groups of atoms (radicals) - OH-, CH 3 -, NH 2 - etc.

Hydrophobic(poorly soluble or insoluble in water) - lipids, fats, fat-like substances, rubber, some organic solvents (benzene, ether), fatty acids, polysaccharides, globular proteins

Hydrophobicity is determined by the presence of non-polar molecular groups:

CH 3 - , CH 2 - CH 3 -

hydrophobic substances can separate aqueous solutions into separate compartments (fractions)

hydrophobic substances are repelled by water and attracted to each other (hydrophobic interactions)

Amphiphilic– phospholipids, fatty acids

· contain molecules and OH-, NH 2 -, COOH- and CH 3 -, CH 2 - CH 3 -

· in wave solutions form a bimolecular layer

2. Provides turgorous phenomena (turgescence) in plant cells

Turgor - elasticity of plant cells, tissues and organs created by intracellular fluid

· determines the shape, elasticity of cells and cell growth, stomatal movements, transpiration (evaporation of water), absorption of water by roots

3. Medium for diffusion (simple and facilitated)

4. Causes osmotic phenomena and osmoregulation

Osmosis -the process of diffusion of water and chemical substances dissolved in it through a semi-permeable membrane along a concentration gradient (toward increased concentration )

· underlies the transport of hydrophilic substances through the cell membrane, the absorption of digestive products in the intestines, water by roots, etc.

5. Entry of substances into the cell (mainly in the form of an aqueous solution)

6. Removal of metabolites (metabolic products) from the cell - excretion

· carried out mainly in the form of aqueous solutions

7. Provides colloidal consistency (system) of the cytoplasm - dispersity of the intracellular environment

8. Ensures the stability of cellular biopolymers - proteins, nucleic acids

9. Determines the functional activity of macromolecules, which depends on the thickness of the hydration (water) shell around them

10. Creates and maintains a chemical environment for physiological and biochemical processes - const pH+ - strict homeostasis for optimal implementation of enzyme functions

11. Creates an environment for chemical reactions of synthesis and decomposition to occur (most of them occur only in the form of aqueous solutions)

12. Water is a chemical reagent (the most important metabolite)

· reactions of hydrolysis, breakdown and digestion of proteins, carbohydrates, lipids, reserve biopolymers, macroergs - ATP, nucleic acids

· participates in synthesis reactions, redox reactions

13. The basis for the formation of the liquid internal environment of the body - blood, lymph, tissue fluid, cerebrospinal fluid

14. Provides transport of inorganic ions and organic molecules in the cell and body (through body fluids, cytoplasm, conductive tissue - xylem, phloem

15. Source of oxygen released during photosynthesis

16. Donor of hydrogen atoms necessary for the reduction of CO 2 assimilation products during photosynthesis

17. Provides stability of subcellular structures (cellular organelles) and cell membranes

18. Thermoregulation (absorption or release of heat due to the rupture or formation of hydrogen bonds) - const t o C

19. Habitat of single-celled organisms

20. Support function (hydrostatic skeleton in animals)

21. Protective function (tear fluid, mucus)

22. Serves as a medium in which fertilization occurs

23. Distribution of gametes, seeds, larval stages of aquatic organisms

24. Promotes the migration of organisms

End of work -

This topic belongs to the section:

Essence of Life

Living matter is qualitatively different from non-living matter in its enormous complexity and high structural and functional orderliness. Living and non-living matter are similar at the elementary chemical level, i.e. Chemical compounds of cell matter..

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All topics in this section:

Mutation process and reserve of hereditary variability
· A continuous mutation process occurs in the gene pool of populations under the influence of mutagenic factors · Recessive alleles mutate more often (encode a phase less resistant to the action of mutagenic

Allele and genotype frequency (genetic structure of the population)
Genetic structure of a population - the ratio of allele frequencies (A and a) and genotypes (AA, Aa, aa) in the gene pool of the population Allele frequency

Cytoplasmic inheritance
· There are data that are incomprehensible from the point of view of the chromosomal theory of heredity of A. Weissman and T. Morgan (i.e., exclusively nuclear localization of genes) · Cytoplasm is involved in the regeneration

Plasmogens of mitochondria
· One myotochondrion contains 4 - 5 circular DNA molecules about 15,000 nucleotide pairs long · Contains genes for: - synthesis of tRNA, rRNA and ribosomal proteins, some aero enzymes

Plasmids
· Plasmids are very short, autonomously replicating circular fragments of bacterial DNA molecules that provide non-chromosomal transmission of hereditary information

Variability
Variability is the common property of all organisms to acquire structural and functional differences from their ancestors.

Mutational variability
Mutations are qualitative or quantitative DNA of the body's cells, leading to changes in their genetic apparatus (genotype) Mutation theory of creation

Causes of mutations
Mutagenic factors (mutagens) - substances and influences that can induce a mutation effect (any factors of the external and internal environment that m

Mutation frequency
· The frequency of mutation of individual genes varies widely and depends on the state of the organism and the stage of ontogenesis (usually increases with age). On average, each gene mutates once every 40 thousand years

Gene mutations (point, true)
The reason is a change in the chemical structure of the gene (violation of the nucleotide sequence in DNA: * gene insertions of a pair or several nucleotides

Chromosomal mutations (chromosomal rearrangements, aberrations)
Causes - caused by significant changes in the structure of chromosomes (redistribution of the hereditary material of chromosomes) In all cases, they arise as a result of

Polyploidy
Polyploidy is a multiple increase in the number of chromosomes in a cell (the haploid set of chromosomes -n is repeated not 2 times, but many times - up to 10 -1

The meaning of polyploidy
1. Polyploidy in plants is characterized by an increase in the size of cells, vegetative and generative organs - leaves, stems, flowers, fruits, roots, etc. , y

Aneuploidy (heteroploidy)
Aneuploidy (heteroploidy) - a change in the number of individual chromosomes that is not a multiple of the haploid set (in this case, one or more chromosomes from a homologous pair is normal

Somatic mutations
Somatic mutations - mutations that occur in the somatic cells of the body · There are gene, chromosomal and genomic somatic mutations

The law of homological series in hereditary variability
· Discovered by N.I. Vavilov based on the study of wild and cultivated flora of five continents 5. The mutation process in genetically close species and genera proceeds in parallel, in

Combinative variability
Combinative variability - variability that arises as a result of the natural recombination of alleles in the genotypes of descendants due to sexual reproduction

Phenotypic variability (modifying or non-hereditary)
Modification variability - evolutionarily fixed adaptive reactions of the organism to changes in the external environment without changing the genotype

The value of modification variability
1. most modifications have adaptive significance and contribute to the body’s adaptation to changes in the external environment 2. can cause negative changes - morphoses

Statistical patterns of modification variability
· Modifications of an individual characteristic or property, measured quantitatively, form a continuous series (variation series); it cannot be built according to an unmeasurable attribute or attribute that is

Variation distribution curve of modifications in the variation series
V - variants of the trait P - frequency of occurrence of variants of the trait Mo - mode, or most

Differences in the manifestation of mutations and modifications
Mutational (genotypic) variability Modification (phenotypic) variability 1. Associated with changes in genotype and karyotype

Features of humans as objects of genetic research
1. Targeted selection of parental pairs and experimental marriages are impossible (impossibility of experimental crossing) 2. Slow generation change, occurring on average every

Methods for studying human genetics
Genealogical method · The method is based on the compilation and analysis of pedigrees (introduced into science at the end of the 19th century by F. Galton); the essence of the method is to trace us

Twin method
· The method consists of studying the patterns of inheritance of traits in monozygotic and fraternal twins (the birth rate of twins is one case per 84 newborns)

Cytogenetic method
· Consists of visual examination of mitotic metaphase chromosomes under a microscope · Based on the method of differential staining of chromosomes (T. Kasperson,

Dermatoglyphics method
· Based on the study of the skin relief on the fingers, palms and plantar surfaces of the feet (there are epidermal projections - ridges that form complex patterns), this feature is inherited

Population - statistical method
· Based on statistical (mathematical) processing of data on inheritance in large groups of the population (populations - groups differing in nationality, religion, race, profession

Somatic cell hybridization method
· Based on the reproduction of somatic cells of organs and tissues outside the body in sterile nutrient media (cells are most often obtained from skin, bone marrow, blood, embryos, tumors) and

Simulation method
· The theoretical basis for biological modeling in genetics is provided by the law of homological series of hereditary variability N.I. Vavilova · For modeling certain

Genetics and medicine (medical genetics)
· Study the causes, diagnostic signs, possibilities of rehabilitation and prevention of hereditary human diseases (monitoring of genetic abnormalities)

Chromosomal diseases
· The reason is a change in the number (genomic mutations) or structure of chromosomes (chromosomal mutations) of the karyotype of the germ cells of the parents (anomalies can occur at different

Polysomy on sex chromosomes
Trisomy - X (Triplo X syndrome); Karyotype (47, XXX) · Known in women; frequency of syndrome 1: 700 (0.1%) N

Hereditary diseases of gene mutations
· Cause - gene (point) mutations (changes in the nucleotide composition of a gene - insertions, substitutions, deletions, transfers of one or more nucleotides; the exact number of genes in humans is unknown

Diseases controlled by genes located on the X or Y chromosome
Hemophilia - blood incoagulability Hypophosphatemia - loss of phosphorus and calcium deficiency in the body, softening of bones Muscular dystrophy - structural disorders

Genotypic level of prevention
1. Search and use of antimutagenic protective substances Antimutagens (protectors) - compounds that neutralize a mutagen before its reaction with a DNA molecule or remove it

Treatment of hereditary diseases
1. Symptomatic and pathogenetic - impact on the symptoms of the disease (the genetic defect is preserved and passed on to offspring) n dietitian

Gene interaction
Heredity is a set of genetic mechanisms that ensure the preservation and transmission of the structural and functional organization of a species in a series of generations from ancestors

Interaction of allelic genes (one allelic pair)
· There are five types of allelic interactions: 1. Complete dominance 2. Incomplete dominance 3. Overdominance 4. Codominance

Complementarity
Complementarity is the phenomenon of interaction of several non-allelic dominant genes, leading to the emergence of a new trait that is absent in both parents

Polymerism
Polymerism is the interaction of non-allelic genes, in which the development of one trait occurs only under the influence of several non-allelic dominant genes (polygene

Pleiotropy (multiple gene action)
Pleiotropy is the phenomenon of the influence of one gene on the development of several traits. The reason for the pleiotropic influence of a gene is in the action of the primary product of this

Breeding Basics
Selection (lat. selektio - selection) - science and branch of agriculture. production, developing the theory and methods of creating new and improving existing plant varieties, animal breeds

Domestication as the first stage of selection
· Cultivated plants and domestic animals descended from wild ancestors; this process is called domestication or domestication The driving force of domestication is the

Centers of origin and diversity of cultivated plants (according to N. I. Vavilov)
Name of the center Geographical location Homeland of cultivated plants

Artificial selection (selection of parental pairs)
· Two types of artificial selection are known: mass and individual. Mass selection is the selection, preservation and use for reproduction of organisms that have

Hybridization (crossing)
· Allows you to combine certain hereditary characteristics in one organism, as well as get rid of undesirable properties · Various crossing systems are used in selection

Inbreeding (inbreeding)
Inbreeding is the crossing of individuals that have a close degree of relationship: brother - sister, parents - offspring (in plants, the closest form of inbreeding occurs when

Unrelated crossing (outbreeding)
· When crossing unrelated individuals, harmful recessive mutations that are in a homozygous state become heterozygous and do not have a negative effect on the viability of the organism

Heterosis
Heterosis (hybrid vigor) is the phenomenon of a sharp increase in the viability and productivity of first-generation hybrids during unrelated crossing (interbreeding).

Induced (artificial) mutagenesis
· The frequency of mutations increases sharply when exposed to mutagens (ionizing radiation, chemicals, extreme environmental conditions, etc.) · Application

Interline hybridization in plants
· Consists of crossing pure (inbred) lines obtained as a result of long-term forced self-pollination of cross-pollinating plants in order to obtain maxima

Vegetative propagation of somatic mutations in plants
· The method is based on the isolation and selection of useful somatic mutations for economic traits in the best old varieties (possible only in plant breeding)

Methods of selection and genetic work I. V. Michurina
1. Systematically distant hybridization a) interspecific: Vladimir cherry x Winkler cherry = Beauty of the North cherry (winter hardiness) b) intergeneric

Polyploidy
Polyploidy is a phenomenon of a multiple of the basic number (n) increase in the number of chromosomes in the somatic cells of the body (the mechanism of formation of polyploids and

Cell engineering
· Cultivation of individual cells or tissues on artificial sterile nutrient media containing amino acids, hormones, mineral salts and other nutritional components (

Chromosome engineering
· The method is based on the possibility of replacing or adding new individual chromosomes in plants · It is possible to decrease or increase the number of chromosomes in any homologous pair - aneuploidy

Animal breeding
· It has a number of features compared to plant selection that objectively make it difficult to carry out: 1. Typically only sexual reproduction is typical (absence of vegetative

Domestication
· Began about 10 - 5 thousand ago in the Neolithic era (weakened the effect of stabilizing natural selection, which led to an increase in hereditary variability and increased selection efficiency

Crossing (hybridization)
· There are two methods of crossing: related (inbreeding) and unrelated (outbreeding) · When selecting a pair, the pedigrees of each manufacturer are taken into account (stud books, teaching

Unrelated crossing (outbreeding)
· Can be intrabreed and interbreed, interspecific or intergeneric (systematically distant hybridization) · Accompanied by the effect of heterosis of F1 hybrids

Checking the breeding qualities of sires by offspring
· There are economic traits that appear only in females (egg production, milk production) · Males participate in the formation of these traits in daughters (it is necessary to check males for c

Selection of microorganisms
· Microorganisms (prokaryotes - bacteria, blue-green algae; eukaryotes - unicellular algae, fungi, protozoa) - widely used in industry, agriculture, medicine

Stages of microorganism selection
I. Search for natural strains capable of synthesizing products necessary for humans II. Isolation of a pure natural strain (occurs in the process of repeated subculture

Objectives of biotechnology
1. Obtaining feed and food protein from cheap natural raw materials and industrial waste (the basis for solving the food problem) 2. Obtaining a sufficient amount

Products of microbiological synthesis
q Feed and food protein q Enzymes (widely used in food, alcohol, brewing, wine, meat, fish, leather, textile, etc.

Stages of the technological process of microbiological synthesis
Stage I – obtaining a pure culture of microorganisms containing only organisms of one species or strain Each species is stored in a separate tube and is sent to production and

Genetic (genetic) engineering
Genetic engineering is a field of molecular biology and biotechnology that deals with the creation and cloning of new genetic structures (recombinant DNA) and organisms with specified characteristics.

Stages of obtaining recombinant (hybrid) DNA molecules
1. Obtaining the initial genetic material - a gene encoding the protein (trait) of interest · The required gene can be obtained in two ways: artificial synthesis or extraction

Achievements of genetic engineering
· The introduction of eukaryotic genes into bacteria is used for the microbiological synthesis of biologically active substances, which in nature are synthesized only by the cells of higher organisms · Synthesis

Problems and prospects of genetic engineering
· Studying the molecular basis of hereditary diseases and developing new methods for their treatment, finding methods for correcting damage to individual genes · Increasing the body's resistance

Chromosome engineering in plants
· It consists in the possibility of biotechnological replacement of individual chromosomes in plant gametes or the addition of new ones · In the cells of each diploid organism there are pairs of homologous chromosomes

Cell and tissue culture method
· The method involves growing individual cells, pieces of tissue or organs outside the body under artificial conditions on strictly sterile nutrient media with constant physico-chemical

Clonal micropropagation of plants
· Cultivation of plant cells is relatively simple, the media is simple and cheap, and cell culture is unpretentious · The method of plant cell culture is that an individual cell or

Hybridization of somatic cells (somatic hybridization) in plants
· Protoplasts of plant cells without rigid cell walls can merge with each other, forming a hybrid cell that has characteristics of both parents · Makes it possible to obtain

Cell engineering in animals
Method of hormonal superovulation and embryo transfer Isolation of dozens of eggs per year from the best cows using the method of hormonal inductive polyovulation (called

Hybridization of somatic cells in animals
· Somatic cells contain the entire volume of genetic information · Somatic cells for cultivation and subsequent hybridization in humans are obtained from the skin, which

Preparation of monoclonal antibodies
· In response to the introduction of an antigen (bacteria, viruses, red blood cells, etc.), the body produces specific antibodies with the help of B lymphocytes, which are proteins called imm

Environmental biotechnology
· Water purification by creating treatment facilities using biological methods q Oxidation of wastewater using biological filters q Recycling of organic and

Bioenergy
Bioenergy is a branch of biotechnology associated with obtaining energy from biomass using microorganisms One of the effective methods for obtaining energy from biomes

Bioconversion
Bioconversion is the transformation of substances formed as a result of metabolism into structurally related compounds under the influence of microorganisms. The purpose of bioconversion is

Engineering enzymology
Engineering enzymology is a field of biotechnology that uses enzymes in the production of specified substances · The central method of engineering enzymology is immobilization

Biogeotechnology
Biogeotechnology - the use of geochemical activity of microorganisms in the mining industry (ore, oil, coal) · With the help of micro-organisms

Boundaries of the biosphere
· Determined by a complex of factors; The general conditions for the existence of living organisms include: 1. the presence of liquid water 2. the presence of a number of biogenic elements (macro- and microelements

Properties of living matter
1. Contain a huge supply of energy capable of producing work 2. The speed of chemical reactions in living matter is millions of times faster than usual due to the participation of enzymes

Functions of living matter
· Performed by living matter in the process of vital activity and biochemical transformations of substances in metabolic reactions 1. Energy – transformation and assimilation by living things

Land biomass
· The continental part of the biosphere - land occupies 29% (148 million km2) · The heterogeneity of land is expressed by the presence of latitudinal zonality and altitudinal zonality

Soil biomass
· Soil is a mixture of decomposed organic and weathered mineral matter; The mineral composition of the soil includes silica (up to 50%), alumina (up to 25%), iron oxide, magnesium, potassium, phosphorus

Biomass of the World Ocean
· The area of ​​the World Ocean (Earth's hydrosphere) occupies 72.2% of the entire surface of the Earth · Water has special properties that are important for the life of organisms - high heat capacity and thermal conductivity

Biological (biotic, biogenic, biogeochemical cycle) cycle of substances
Biotic cycle of substances is a continuous, planetary, relatively cyclical, uneven in time and space, regular distribution of substances

Biogeochemical cycles of individual chemical elements
· Biogenic elements circulate in the biosphere, i.e. they perform closed biogeochemical cycles that function under the influence of biological (life activity) and geological

Nitrogen cycle
· Source of N2 – molecular, gaseous, atmospheric nitrogen (not absorbed by most living organisms, because it is chemically inert; plants can only absorb nitrogen bound

Carbon cycle
· The main source of carbon is carbon dioxide in the atmosphere and water · The carbon cycle is carried out through the processes of photosynthesis and cellular respiration · The cycle begins with

The water cycle
· Carried out using solar energy · Regulated by living organisms: 1. absorption and evaporation by plants 2. photolysis in the process of photosynthesis (decomposition

Sulfur cycle
· Sulfur is a biogenic element of living matter; found in proteins as amino acids (up to 2.5%), part of vitamins, glycosides, coenzymes, found in vegetable essential oils

Flow of energy in the biosphere
· The source of energy in the biosphere is continuous electromagnetic radiation from the sun and radioactive energy q 42% of solar energy is reflected from clouds, the atmosphere of dust and the surface of the Earth in

The emergence and evolution of the biosphere
· Living matter, and with it the biosphere, appeared on Earth as a result of the emergence of life in the process of chemical evolution about 3.5 billion years ago, which led to the formation of organic substances

Noosphere
Noosphere (literally, sphere of mind) is the highest stage of development of the biosphere, associated with the emergence and formation of civilized humanity in it, when its mind

Signs of the modern noosphere
1. An increasing amount of extracted lithosphere materials - an increase in the development of mineral deposits (now it exceeds 100 billion tons per year) 2. Massive consumption

Human influence on the biosphere
· The current state of the noosphere is characterized by the ever-increasing prospect of an ecological crisis, many aspects of which are already fully manifested, creating a real threat to existence

Energy production
q The construction of hydroelectric power stations and the creation of reservoirs causes the flooding of large areas and the displacement of people, rising groundwater levels, soil erosion and waterlogging, landslides, loss of arable land

Food production. Soil depletion and pollution, reduction in fertile soil area
q Arable lands occupy 10% of the Earth’s surface (1.2 billion hectares) q The reason is overexploitation, imperfect agricultural production: water and wind erosion and the formation of ravines,

Declining natural biodiversity
q Human economic activity in nature is accompanied by changes in the number of animal and plant species, the extinction of entire taxa, and a decrease in the diversity of living things. q Currently

Acid precipitation
q Increased acidity of rain, snow, fog due to the release of sulfur and nitrogen oxides into the atmosphere from fuel combustion q Acid precipitation reduces crop yields and destroys natural vegetation

Ways to solve environmental problems
· Man will continue to exploit the resources of the biosphere on an ever-increasing scale, since this exploitation is an indispensable and main condition for the very existence of h

Sustainable consumption and management of natural resources
q Maximum complete and comprehensive extraction of all minerals from deposits (due to imperfect extraction technology, only 30-50% of reserves are extracted from oil deposits q Rec

Ecological strategy for agricultural development
q Strategic direction - increasing productivity to provide food for a growing population without increasing the area under cultivation q Increasing the yield of agricultural crops without negative impacts

Properties of living matter
1. Unity of elemental chemical composition (98% is carbon, hydrogen, oxygen and nitrogen) 2. Unity of biochemical composition - all living organs

Hypotheses about the origin of life on Earth
· There are two alternative concepts about the possibility of the origin of life on Earth: q abiogenesis – the emergence of living organisms from inorganic substances

Stages of development of the Earth (chemical prerequisites for the emergence of life)
1. Stellar stage of the history of the Earth q The geological history of the Earth began more than 6 times ago. years ago, when the Earth was a hot place over 1000

The emergence of the process of self-reproduction of molecules (biogenic matrix synthesis of biopolymers)
1. Occurred as a result of the interaction of coacervates with nucleic acids 2. All necessary components of the process of biogenic matrix synthesis: - enzymes - proteins - etc.

Prerequisites for the emergence of the evolutionary theory of Charles Darwin
Socio-economic prerequisites 1. In the first half of the 19th century. England has become one of the most economically developed countries in the world with a high level of

· Set forth in Charles Darwin’s book “On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Breeds in the Struggle for Life,” which was published

Variability
Justification of the variability of species · To substantiate the position on the variability of living beings, Charles Darwin used common

Correlative variability
· A change in the structure or function of one part of the body causes a coordinated change in another or others, since the body is an integral system, the individual parts of which are closely interconnected

The main provisions of the evolutionary teachings of Charles Darwin
1. All species of living beings inhabiting the Earth were never created by anyone, but arose naturally 2. Having arisen naturally, species slowly and gradually

Development of ideas about the species
· Aristotle - used the concept of species when describing animals, which had no scientific content and was used as a logical concept · D. Ray

Species criteria (signs of species identification)
· The importance of species criteria in science and practice - determination of the species identity of individuals (species identification) I. Morphological - similarity of morphological inheritances

Population types
1. Panmictic - consist of individuals that reproduce sexually and cross-fertilize. 2. Clonal - from individuals that reproduce only without

Mutation process
Spontaneous changes in the hereditary material of germ cells in the form of gene, chromosomal and genomic mutations occur constantly throughout the entire period of life under the influence of mutations

Insulation
Isolation - stopping the flow of genes from population to population (limiting the exchange of genetic information between populations) The meaning of isolation as a fa

Primary insulation
· Not directly related to the action of natural selection, is a consequence of external factors · Leads to a sharp decrease or cessation of migration of individuals from other populations

Environmental insulation
· Arises on the basis of ecological differences in the existence of different populations (different populations occupy different ecological niches) v For example, trout of Lake Sevan p

Secondary isolation (biological, reproductive)
· Is crucial in the formation of reproductive isolation · Arises as a result of intraspecific differences in organisms · Arose as a result of evolution · Has two iso

Migrations
Migration is the movement of individuals (seeds, pollen, spores) and their characteristic alleles between populations, leading to changes in the frequencies of alleles and genotypes in their gene pools Common with

Population waves
Population waves (“waves of life”) - periodic and non-periodic sharp fluctuations in the number of individuals in a population under the influence of natural causes (S.S.

The meaning of population waves
1. Leads to an undirected and sharp change in the frequencies of alleles and genotypes in the gene pool of populations (random survival of individuals during the wintering period can increase the concentration of this mutation by 1000 r

Genetic drift (genetic-automatic processes)
Genetic drift (genetic-automatic processes) is a random, non-directional change in the frequencies of alleles and genotypes, not caused by the action of natural selection.

Result of genetic drift (for small populations)
1. Causes the loss (p = 0) or fixation (p = 1) of alleles in a homozygous state in all members of the population, regardless of their adaptive value - homozygotization of individuals

Natural selection is the guiding factor of evolution
Natural selection is the process of preferential (selective, selective) survival and reproduction of the fittest individuals and non-survival or non-reproduction

The struggle for existence Forms of natural selection
Driving selection (Described by Charles Darwin, modern teaching developed by D. Simpson, English) Driving selection - selection in

Stabilizing selection
· The theory of stabilizing selection was developed by Russian academician. I. I. Shmagauzen (1946) Stabilizing selection - selection operating in stable

Other forms of natural selection
Individual selection - selective survival and reproduction of individual individuals that have an advantage in the struggle for existence and the elimination of others

Main features of natural and artificial selection
Natural selection Artificial selection 1. Arose with the emergence of life on Earth (about 3 billion years ago) 1. Arose in non-

General characteristics of natural and artificial selection
1. Initial (elementary) material - individual characteristics of the organism (hereditary changes - mutations) 2. Are carried out according to the phenotype 3. Elementary structure - populations

The struggle for existence is the most important factor in evolution
The struggle for existence is a complex of relationships between an organism and abiotic (physical living conditions) and biotic (relationships with other living organisms) factors

Reproduction intensity
v One individual roundworm produces 200 thousand eggs per day; the gray rat gives birth to 5 litters per year of 8 pups, which become sexually mature at three months of age; the offspring of one daphnia reaches

Interspecies struggle for existence
· Occurs between individuals of populations of different species · Less acute than intraspecific, but its tension increases if different species occupy similar ecological niches and have

Combating unfavorable abiotic environmental factors
· Observed in all cases when individuals of a population find themselves in extreme physical conditions (excessive heat, drought, severe winter, excess humidity, infertile soils, harsh

Major discoveries in the field of biology after the creation of STE
1. Discovery of the hierarchical structures of DNA and protein, including the secondary structure of DNA - the double helix and its nucleoprotein nature 2. Deciphering the genetic code (its triplet structure

Signs of the endocrine system organs
1. They are relatively small in size (lobes or several grams) 2. Anatomically unrelated to each other 3. They synthesize hormones 4. They have an abundant network of blood vessels

Characteristics (signs) of hormones
1. Formed in the endocrine glands (neurohormones can be synthesized in neurosecretory cells) 2. High biological activity - the ability to quickly and strongly change the int

Chemical nature of hormones
1. Peptides and simple proteins (insulin, somatotropin, tropic hormones of the adenohypophysis, calcitonin, glucagon, vasopressin, oxytocin, hypothalamic hormones) 2. Complex proteins - thyrotropin, lute

Hormones of the middle (intermediate) lobe
Melanotropic hormone (melanotropin) - exchange of pigments (melanin) in the integumentary tissues Hormones of the posterior lobe (neurohypophysis) - oxytrcin, vasopressin

Thyroid hormones (thyroxine, triiodothyronine)
The composition of thyroid hormones certainly includes iodine and the amino acid tyrosine (0.3 mg of iodine is released daily as part of the hormones, therefore a person should receive daily with food and water

Hypothyroidism (hypothyroidism)
The cause of hypotherosis is a chronic deficiency of iodine in food and water. The lack of hormone secretion is compensated by the proliferation of gland tissue and a significant increase in its volume

Cortical hormones (mineralkorticoids, glucocorticoids, sex hormones)
The cortical layer is formed from epithelial tissue and consists of three zones: glomerular, fascicular and reticular, having different morphologies and functions. Hormones are classified as steroids - corticosteroids

Adrenal medulla hormones (adrenaline, norepinephrine)
- The medulla consists of special chromaffin cells, stained yellow (these same cells are located in the aorta, the branch of the carotid artery and in the sympathetic nodes; they all make up

Pancreatic hormones (insulin, glucagon, somatostatin)
Insulin (secreted by beta cells (insulocytes), is the simplest protein) Functions: 1. Regulation of carbohydrate metabolism (the only sugar reduction

Testosterone
Functions: 1. Development of secondary sexual characteristics (body proportions, muscles, beard growth, body hair, mental characteristics of a man, etc.) 2. Growth and development of reproductive organs

Ovaries
1. Paired organs (size about 4 cm, weight 6-8 g), located in the pelvis, on both sides of the uterus 2. Consist of a large number (300-400 thousand) so-called. follicles - structure

Estradiol
Functions: 1. Development of female genital organs: oviducts, uterus, vagina, mammary glands 2. Formation of secondary sexual characteristics of the female sex (physique, figure, fat deposition, etc.)

Endocrine glands (endocrine system) and their hormones
Endocrine glands Hormones Functions Pituitary gland: - anterior lobe: adenohypophysis - middle lobe - posterior

Reflex. Reflex arc
Reflex is the body’s response to irritation (change) of the external and internal environment, carried out with the participation of the nervous system (the main form of activity

Feedback Mechanism
· The reflex arc does not end with the body’s response to stimulation (the work of the effector). All tissues and organs have their own receptors and afferent nerve pathways that connect to the senses.

Spinal cord
1. The most ancient part of the central nervous system of vertebrates (it first appears in cephalochordates - the lancelet) 2. During embryogenesis, it develops from the neural tube 3. It is located in the bone

Skeletal-motor reflexes
1. Knee reflex (the center is localized in the lumbar segment); rudimentary reflex from animal ancestors 2. Achilles reflex (in the lumbar segment) 3. Plantar reflex (with

Conductor function
· The spinal cord has a two-way connection with the brain (stem and cerebral cortex); through the spinal cord, the brain is connected to the receptors and executive organs of the body

Brain
· The brain and spinal cord develop in the embryo from the outer germ layer - ectoderm · Located in the cavity of the brain skull · Covered (like the spinal cord) with three layers

Medulla
2. During embryogenesis, it develops from the fifth medullary vesicle of the neural tube of the embryo 3. It is a continuation of the spinal cord (the lower boundary between them is the place where the root emerges

Reflex function
1. Protective reflexes: coughing, sneezing, blinking, vomiting, lacrimation 2. Food reflexes: sucking, swallowing, secretion of juice from the digestive glands, motility and peristalsis

Midbrain
1. In the process of embryogenesis from the third medullary vesicle of the neural tube of the embryo 2. Covered with white matter, gray matter inside in the form of nuclei 3. Has the following structural components

Functions of the midbrain (reflex and conduction)
I. Reflex function (all reflexes are innate, unconditioned) 1. Regulation of muscle tone when moving, walking, standing 2. Orienting reflex

Thalamus (visual thalamus)
· Represents paired clusters of gray matter (40 pairs of nuclei), covered with a layer of white matter, inside – the third ventricle and reticular formation · All nuclei of the thalamus are afferent, sensory

Functions of the hypothalamus
1. Higher center of nervous regulation of the cardiovascular system, permeability of blood vessels 2. Center of thermoregulation 3. Regulation of water-salt balance organ

Functions of the cerebellum
· The cerebellum is connected to all parts of the central nervous system; skin receptors, proprioceptors of the vestibular and motor apparatus, subcortex and cerebral cortex · The functions of the cerebellum investigate the path

Telencephalon (cerebrum, forebrain cerebrum)
1. During embryogenesis, it develops from the first brain vesicle of the neural tube of the embryo 2. Consists of two hemispheres (right and left), separated by a deep longitudinal fissure and connected

Cerebral cortex (cloak)
1. In mammals and humans, the surface of the cortex is folded, covered with convolutions and grooves, providing an increase in surface area (in humans it is about 2200 cm2

Functions of the cerebral cortex
Study methods: 1. Electrical stimulation of individual areas (method of “implanting” electrodes into areas of the brain) 3. 2. Removal (extirpation) of individual areas

Sensory zones (regions) of the cerebral cortex
· They represent the central (cortical) sections of the analyzers; sensitive (afferent) impulses from the corresponding receptors approach them · Occupy a small part of the cortex

Functions of association zones
1. Communication between different areas of the cortex (sensory and motor) 2. Combination (integration) of all sensitive information entering the cortex with memory and emotions 3. Decisive

Features of the autonomic nervous system
1. Divided into two sections: sympathetic and parasympathetic (each of them has a central and peripheral part) 2. Does not have its own afferent (

Features of the parts of the autonomic nervous system
Sympathetic division Parasympathetic division 1. The central ganglia are located in the lateral horns of the thoracic and lumbar segments of the spinal column

Functions of the autonomic nervous system
· Most organs of the body are innervated by both the sympathetic and parasympathetic systems (dual innervation) · Both departments exert three types of actions on the organs - vasomotor,

The influence of the sympathetic and parasympathetic divisions of the autonomic nervous system
Sympathetic department Parasympathetic department 1. Speeds up the rhythm, increases the strength of heart contractions 2. Dilates the coronary vessels

Higher nervous activity of man
Mental mechanisms of reflection: Mental mechanisms of designing the future - sensibly

Features (signs) of unconditioned and conditioned reflexes
Unconditioned reflexes Conditioned reflexes 1. Innate specific reactions of the body (passed on by inheritance) - genetically determined

Methodology for developing (forming) conditioned reflexes
· Developed by I.P. Pavlov on dogs when studying salivation under the influence of light or sound stimuli, odors, touches, etc. (the duct of the salivary gland was brought out through a slit

Conditions for the development of conditioned reflexes
1. The indifferent stimulus must precede the unconditioned one (anticipatory action) 2. The average strength of the indifferent stimulus (with low and high strength the reflex may not form

The meaning of conditioned reflexes
1. They form the basis of learning, obtaining physical and mental skills 2. Subtle adaptation of vegetative, somatic and mental reactions to conditions with

Induction (external) braking
o Develops under the influence of an extraneous, unexpected, strong irritant from the external or internal environment v Severe hunger, full bladder, pain or sexual arousal

Extinction conditioned inhibition
· Develops when the conditioned stimulus is systematically not reinforced by the unconditioned v If the conditioned stimulus is repeated at short intervals without reinforcement

The relationship between excitation and inhibition in the cerebral cortex
Irradiation is the spread of excitation or inhibition processes from the source of their occurrence to other areas of the cortex. An example of irradiation of the excitation process is

Causes of sleep
· There are several hypotheses and theories of the causes of sleep: Chemical hypothesis - the cause of sleep is poisoning of brain cells with toxic waste products, image

REM (paradoxical) sleep
· Occurs after a period of slow-wave sleep and lasts 10-15 minutes; then again gives way to slow-wave sleep; repeats 4-5 times during the night Characterized by rapid

Features of human higher nervous activity
(differences from the GNI of animals) · Channels for obtaining information about factors of the external and internal environment are called signaling systems · The first and second signaling systems are distinguished

Features of higher nervous activity of humans and animals
Animal Human 1. Obtaining information about environmental factors only using the first signal system (analyzers) 2. Specific

Memory as a component of higher nervous activity
Memory is a set of mental processes that ensure the preservation, consolidation and reproduction of previous individual experience v Basic memory processes

Analyzers
· A person receives all the information about the external and internal environment of the body necessary to interact with it using the senses (sensory systems, analyzers) v The concept of analysis

Structure and functions of analyzers
· Each analyzer consists of three anatomically and functionally related sections: peripheral, conductive and central · Damage to one of the parts of the analyzer

The meaning of analyzers
1. Information to the body about the state and changes in the external and internal environment 2. The emergence of sensations and the formation on their basis of concepts and ideas about the surrounding world, i.e. e.

Choroid (middle)
· Located under the sclera, rich in blood vessels, consists of three parts: the anterior one - the iris, the middle one - the ciliary body and the posterior one - the vascular tissue itself

Features of photoreceptor cells of the retina
Rods Cones 1. Number 130 million 2. Visual pigment – ​​rhodopsin (visual purple) 3. Maximum number per n

Lens
· Located behind the pupil, it has the shape of a biconvex lens with a diameter of about 9 mm, is absolutely transparent and elastic. Covered with a transparent capsule to which the ligaments of the ciliary body are attached

Functioning of the eye
· Visual reception begins with photochemical reactions that begin in the rods and cones of the retina and consist in the disintegration of visual pigments under the influence of light quanta. Exactly this

Vision hygiene
1. Prevention of injuries (safety glasses in production with traumatic objects - dust, chemicals, shavings, splinters, etc.) 2. Eye protection from too bright light - sun, electrical

Outer ear
· Representation of the auricle and external auditory canal · Auricle - freely protruding on the surface of the head

Middle ear (tympanic cavity)
· Lies inside the pyramid of the temporal bone · Filled with air and communicates with the nasopharynx through a tube 3.5 cm long and 2 mm in diameter - the Eustachian tube Function of the Eustachians

Inner ear
· Located in the pyramid of the temporal bone · Includes a bony labyrinth, which is a complex canal structure · Inside the bones

Perception of sound vibrations
· The auricle picks up sounds and directs them to the external auditory canal. Sound waves cause vibrations of the eardrum, which are transmitted from it through the system of levers of the auditory ossicles (

Hearing hygiene
1. Prevention of injuries to the hearing organs 2. Protection of the hearing organs from excessive strength or duration of sound stimulation - the so-called. "noise pollution", especially in noisy industrial environments

Biosphere
1. Represented by cellular organelles 2. Biological mesosystems 3. Possible mutations 4. Histological method of research 5. Beginning of metabolism 6. About

“Structure of a eukaryotic cell” 9. Cell organelle containing DNA 10. Has pores 11. Performs a compartmental function in the cell 12. Function

Cell center
Test thematic digital dictation on the topic “Cell Metabolism” 1. Carried out in the cytoplasm of the cell 2. Requires specific enzymes

Thematic digital programmed dictation
on the topic “Energy metabolism” 1. Hydrolysis reactions are carried out 2. The final products are CO2 and H2 O 3. The final product is PVC 4. NAD is reduced

Oxygen stage
Thematic digital programmed dictation on the topic “Photosynthesis” 1. Photolysis of water occurs 2. Reduction occurs

“Cell metabolism: Energy metabolism. Photosynthesis. Protein biosynthesis" 1. Carried out in autotrophs 52. Transcription is carried out 2. Associated with the functioning

The main characteristics of the eukaryotic kingdoms
Plant Kingdom Animal Kingdom 1. They have three subkingdoms: – lower plants (true algae) – red algae

Features of types of artificial selection in breeding
Mass selection Individual selection 1. Many individuals with the most pronounced characteristics are allowed to reproduce

General characteristics of mass and individual selection
1. Carried out by man through artificial selection 2. Only individuals with the most pronounced desired trait are allowed for further reproduction 3. Can be repeated

Water is a unique substance. It is distributed everywhere on our planet. Try to imagine what our life would be like without the H2O molecule? And there is nothing to imagine - there would be no life on our planet. Humans are 70% water. The younger the body, the more it contains, and with age this amount decreases. For example, let's take an embryo - the percentage of H2O in it is 90%.

In the article, we invite you to highlight everything in the cell and consider each in detail. It is important to mention that it is contained there in two forms: free and bound. We'll deal with this a little later.

Water

Everyone knows that water plays a very important, or rather, key role in our lives. Without it, our planet would be a dead, lifeless desert. Scientists are still studying water and its role in the human body.

We have already said that water is found in our cells in free and bound forms. The first serves to distribute substances - to transfer them into and out of the cell. And the last one is observed:

• between fibers;
• membranes;
• protein molecules;
• cellular structures.

Both free and bound water in the cell necessarily perform some functions, which we will talk about later. And now a few words about how the H2O molecule itself is organized.

Molecule

To begin with, let's denote the molecular formula of water: H2O. This is a very common substance on the planet, and you should remember it, because the molecular formula of water is found quite often in different fields of knowledge. By the way, it is found in all human organs, even in tooth enamel and bones, although its percentage there is very small - 10% and 20%, respectively.

As we have already said, the younger the body, the more water it contains. Scientists have suggested that we age because protein cannot bind large amounts of water. But this, however, is only a hypothesis.

Functions

Now let's highlight more of them clearly from the list below:

• H2O can act as a solvent, since almost all chemical reactions are ionic and occur in water. It should be noted that there are hydrophilic substances (which dissolve, for example, alcohol, sugar, amino acids, and so on), but there are also hydrophobic ones (fatty acids, cellulose, and others).
• Water can act as a reagent.
• Performs transport, thermoregulatory and structural functions.

We propose to consider each of them separately. Let's go in order, the first on our list is the solvent function.

Solvent

The functions of water in the cell are numerous, but one of the most important is to help facilitate many reactions. The H2O molecule can act as a solvent. Almost all reactions occurring in a cell are ionic, that is, the medium in which they can take place is water.

Reagent

The next functions of water in a cell are its participation in chemical reactions taking place in the body as a reagent. These include:

• hydrolysis;
• polymerization;
• photosynthesis and so on.

Now a little about that. In chemistry, this is the name for a substance participating in some chemical reactions. The most important thing is that although it participates in the reaction, it is not the object of processing. Reagents in the laboratory (also called reagents) are a fairly common phenomenon.

Water, as a reagent, is involved in the composition of other substances needed by the body.

Transport function

Why do we live? Our body exists only because the cells of which it consists are alive. And they should thank their unique structure and some of the capabilities of the H2O molecule. We have already mentioned that water is an integral part of our body, and each cell contains these unique molecules, or rather, is in first place in its composition.

The transport function of water in the cell is another purpose of H2O in our body. Water has a certain feature - penetration into the intercellular space, thanks to which nutrients enter the cell.

It is also worth knowing that blood and lymph also contain water, and its lack leads to some consequences: hemorrhages or thrombosis.

Thermoregulation

What functions of water in a cell have we not yet figured out? Of course, thermoregulation. We said that water can absorb heat and retain it for a long time. Thus, H2O can protect the cell from hypothermia or overheating. The function of thermoregulation is needed not only for individual cells, but also for the entire organism as a whole.

Structural function

We have already listed them, but one more purpose remains to be discussed - maintaining the structure of cells.

Have you ever tried to compress liquid water? Even in laboratory conditions this is extremely difficult to achieve. This property of water is necessary in order to maintain the shape and structure of each cell.

Remember forever: without water life is impossible. We experience thirst when the body loses about 3% of water, and with a loss of 20%, the cells die, and, consequently, the person too. Watch how much water you drink.

Water (H 2 O) is the most important inorganic substance of the cell. In a cell, in quantitative terms, water ranks first among other chemical compounds. Water performs various functions: maintaining the volume, elasticity of the cell, participating in all chemical reactions. All biochemical reactions occur in aqueous solutions. The higher the metabolic rate in a particular cell, the more water it contains.

Pay attention!

Water in a cell is in two forms: free and bound.

Free water located in intercellular spaces, vessels, vacuoles, and organ cavities. It serves to transport substances from the environment into the cell and vice versa.
Bound water is part of some cellular structures, located between protein molecules, membranes, fibers and is connected to some proteins.
Water has a number of properties that are extremely important for living organisms.

Water molecule structure

The unique properties of water are determined by the structure of its molecule.

Hydrogen bonds are formed between individual water molecules, which determine the physical and chemical properties of water.
The characteristic arrangement of electrons in a water molecule gives it electrical asymmetry. The more electronegative oxygen atom attracts the electrons of the hydrogen atoms more strongly, resulting in a water molecule dipole(has polarity). Each of the two hydrogen atoms has a partially positive charge, and the oxygen atom carries a partially negative charge.

The partially negative charge of the oxygen atom of one water molecule is attracted by the partially positive hydrogen atoms of other molecules. Thus, each water molecule tends to connect hydrogen bond with four neighboring water molecules.

Properties of water

Since water molecules are polar, water has the property of dissolving polar molecules of other substances.
Substances that are soluble in water are called hydrophilic(salts, sugars, simple alcohols, amino acids, inorganic acids). When a substance goes into solution, its molecules or ions can move more freely and, therefore, the reactivity of the substance increases.

Substances that are insoluble in water are called hydrophobic(fats, nucleic acids, some proteins). Such substances can form interfaces with water at which many chemical reactions take place. Therefore, the fact that water does not dissolve some substances is also very important for living organisms.

Water has a high specific heat capacity, i.e. the ability to absorb thermal energy with a minimal increase in its own temperature. To break the numerous hydrogen bonds present between water molecules, a large amount of energy must be absorbed. This property of water ensures the maintenance of thermal balance in the body. The large heat capacity of water protects body tissues from rapid and strong temperature increases.
To evaporate water, quite a lot of energy is required. The use of a significant amount of energy to break hydrogen bonds during evaporation helps to cool it. This property of water protects the body from overheating.

Example:

Examples of this include transpiration in plants and sweating in animals.

Water also has high thermal conductivity, ensuring uniform distribution of heat throughout the body.

Pay attention!

High specific heat capacity and high thermal conductivity makes water an ideal liquid for maintaining thermal equilibrium of cells and organisms.

Water practically does not shrink, creating turgor pressure, determining the volume and elasticity of cells and tissues.

Example:

The hydrostatic skeleton maintains shape in roundworms, jellyfish and other organisms.

Thanks to the adhesive forces of molecules, a film is created on the surface of the water, which has such a characteristic as surface tension.

Example:

Due to the force of surface tension, capillary blood flow, ascending and descending currents of solutions in plants occur.

Among the physiologically important properties of water is its ability to dissolve gases(O 2, CO 2, etc.).

Water is also a source of oxygen and hydrogen released during photolysis during the light phase of photosynthesis.

Biological functions of water

• Water ensures the movement of substances in the cell and body, the absorption of substances and the removal of metabolic products. In nature, water carries waste products into soils and water bodies.
• Water is an active participant in metabolic reactions.
• Water is involved in the formation of lubricating fluids and mucus, secretions and juices in the body (these fluids are found in the joints of vertebrates, in the pleural cavity, in the pericardial sac).
• Water is part of mucus, which facilitates the movement of substances through the intestines and creates a moist environment on the mucous membranes of the respiratory tract. The secretions secreted by some glands and organs are also water-based: saliva, tears, bile, sperm, etc.

Water plays a vital role in the life of cells and living organisms in general. In addition to the fact that it is part of their composition, for many organisms it is also a habitat. The role of water in a cell is determined by its properties. These properties are quite unique and are associated mainly with the small size of water molecules, with the polarity of its molecules and with their ability to connect with each other through hydrogen bonds.

Water molecules have a nonlinear spatial structure. The atoms in a water molecule are held together by polar covalent bonds, which bind one oxygen atom to two hydrogen atoms. The polarity of covalent bonds (i.e., uneven distribution of charges) is explained in this case by the strong electronegativity of the oxygen atoms relative to the hydrogen atom; The oxygen atom pulls electrons from shared electron pairs.

As a result, a partially negative charge appears on the oxygen atom, and a partially positive charge appears on the hydrogen atoms. Hydrogen bonds occur between the oxygen and hydrogen atoms of neighboring molecules.

Thanks to the formation of hydrogen bonds, water molecules form one another, which determines its initial state under normal conditions.

Water is excellent solvent for polar substances, such as salts, sugars, alcohols, acids, etc. Substances that are highly soluble in water are called hydrophilic.

Water does not dissolve or mix with absolutely non-polar substances such as fats or oils, since it cannot form hydrogen bonds with them. Substances that are insoluble in water are called hydrophobic.

Water has high specific heat capacity. Breaking the hydrogen bonds that hold water molecules together requires the absorption of a large amount of energy. This property ensures the maintenance of the body's thermal balance during significant temperature changes in the environment. In addition, water has high thermal conductivity, which allows the body to maintain the same temperature throughout its entire volume.

Water also has high heat of vaporization, i.e. the ability of molecules to carry away a significant amount of heat, cooling the body. This property of water is used in sweating in mammals, thermal shortness of breath in crocodiles and transpiration in plants, preventing them from overheating.

It is exclusively characteristic of water high surface tension. This property is very important for adsorption processes, for the movement of solutions through tissues (blood circulation, ascending and descending currents in the body of plants). Many small organisms benefit from surface tension: it allows them to float on water or glide across its surface.

Biological functions of water

Transport. Water ensures the movement of substances in the cell and body, the absorption of substances and the removal of metabolic products.

Metabolic. Water is the medium for all biochemical reactions in the cell. Its molecules participate in many chemical reactions, for example in the formation or hydrolysis of polymers. In the process of photosynthesis, water is an electron donor and a source of hydrogen atoms. It is also a source of free oxygen.

Structural. The cytoplasm of cells contains from 60 to 95% water. In plants, water determines the turgor of cells, and in some animals it performs supporting functions, being a hydrostatic skeleton (round and annelids, echinoderms).

Water is involved in the formation of lubricating fluids (synovial in the joints of vertebrates; pleural in the pleural cavity, pericardial in the pericardial sac) and mucus (which facilitate the movement of substances through the intestines and create a moist environment on the mucous membranes of the respiratory tract). It is part of saliva, bile, tears, sperm, etc.

Mineral salts

Salt molecules in an aqueous solution dissociate into cations and anions. The most important cations are: K +, Na +, Ca 2+, Mg 2+ and anions: Cl -, H 2 PO 4 -, HPO 4 2-, HCO 3 -, NO 3 -, SO 4 2-. Not only the content, but also the ratio of ions in the cell is significant.

The difference between the amounts of cations and anions on the surface and inside the cell ensures the occurrence of an action potential, which underlies nerve and muscle excitation. The difference in ion concentrations on different sides of the membrane is associated with the active transfer of substances across the membrane, as well as energy conversion.

Phosphoric acid anions create a phosphate buffer system that maintains the pH of the body's intracellular environment at 6.9.

Carbonic acid and its anions create a bicarbonate buffer system that maintains the pH of the extracellular environment (blood plasma) at 7.4.

Some ions are involved in the activation of enzymes, the creation of osmotic pressure in the cell, in the processes of muscle contraction, blood clotting, etc.

Some cations and anions can be included in complexes with various substances (for example, phosphoric acid anions are part of phospholipids, ATP, nucleotides, etc.; Fe 2+ ion is part of hemoglobin, etc.).