Home Grape Biological terms what type is. Basic biological terms (Glossary). What you need to know for the OGE in biology in order to pass it

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Biological terms what type is. Basic biological terms (Glossary). What you need to know for the OGE in biology in order to pass it

Completing the missing information - complete the sentence (advanced level)

You can repeat the material for solving tasks in the General Biology section

1. The branch of science and industry that develops ways to use biological objects in modern production is

Answer: biotechnology.

2. Science that studies the shape and structure of individual organs, their systems and the whole organism as a whole is

Answer: anatomy.

3. Science that studies the origin and evolution of man as a biosocial species, the formation of human races, is

Answer: anthropology.

4. "Recording" of hereditary information occurs at ... the level of the organization.

Answer: molecular.

5. Seasonal changes in wildlife are studied by science

Answer: phenology.

6. Microbiology as an independent science took shape thanks to the work

Answer: L. Pasteur (Pasteur)

7. For the first time, a system of classification of animals and plants was proposed by

Answer: K. Linnaeus (Linnaeus)

8. The founder of the first evolutionary theory was

Answer: J.-B. Lamarck (Lamarck)

9. The founder of medicine is considered

Answer: Hippocrates (Hippocrates).

10. The main provisions of the theory of homologous organs and the law of embryonic similarity were formulated by

Answer: K. Baer (Baer).

11. In science, hypotheses are tested using ... method.

Answer: experimental.

12. The founder of the experimental method in biology is considered

Answer: I.P. Pavlova (Pavlov).

13. The set of techniques and operations used in building a system of reliable knowledge is ... a method.

Answer: scientific.

14. The highest form of experiment is considered

Answer: simulation.

15. The ability of organisms to reproduce itself is

Answer: reproduction.

16. The section of biology that studies the tissues of multicellular organisms is

Answer: histology.

17. The law of biogenic migration of atms formulated

18. The law of linked inheritance of traits discovered

Answer: T. Morgan (Morgan).

19. The law of irreversibility of evolution formulated

Answer: L. Dollo (Dollo).

20. The law of correlation of parts of the organism, or the ratio of organs formulated

Answer: J. Cuvier (Cuvier).

21. The law of changing phases (directions) of evolution was formulated

Answer: A. N. Severtsov (Severtsov).

22. The doctrine of the biosphere was developed by

Answer: V.I. Vernadsky (Vernadsky).

23. The law of physical and chemical unity of living matter formulated

Answer: V.I. Vernadsky (Vernadsky).

24. The founder of evolutionary paleontology was

Answer: V.O. Kovalevsky (Kovalevsky).

25. Science that studies the structure and life of the cell

Answer: cytology.

26. Science that studies animal behavior is

Answer: Ethology.

27. The science involved in planning quantitative biological experiments and processing the results by methods of mathematical statistics is

Answer: biometrics.

28. Science, the general properties and manifestations of life at the cellular level are studied, is

Answer: cytology.

29. Science that studies the historical development of living nature is

Answer: evolution.

30. The science of algae is

Answer: algology.

31. The science of insects is

Answer: entomology.

32. The inheritance of hemophilia in humans is established using ... method.

Answer: genealogical.

33. When studying cells with the help of modern devices, they use ... the method.

Answer: instrumental.

34. The impact of living and working conditions on health studies

The answer is hygiene.

35. The processes of biosynthesis of organic compounds occur at ... the level of organization of living matter.

Answer: molecular.

36. Dubrava is an example ... of the level of organization of living matter.

Answer: biogeocenotic.

37. Storage and transmission of hereditary information occurs at ... the level of organization of living matter.

Answer: molecular.

38. To study natural phenomena in given conditions allows the method

Answer: experiment.

39. The internal structure of mitochondria allows you to study ... a microscope.

Answer: electronic.

40. Changes occurring in the somatic cell during mitosis, allows you to study the method

Answer: microscopy.

41. The genetics method allows to reveal the nature and type of inheritance of traits from generation to generation based on the study of a person's pedigree.

Answer: genealogical.

42. Transcription and translation takes place at ... the level of organization of the living.

Answer: molecular.

43. Taxonomy uses the method

Answer: classifications.

44. A sign of a living thing, the essence of which is the ability of organisms to reproduce their own kind, is

Answer: reproduction.

45. A sign of a living thing, the essence of which is the ability of living systems to maintain the relative constancy of their internal environment, is

Answer: homeostasis.

46. One of the most important principles of the organization of biological systems is their

The answer is openness.

47. The structure of plastids is studied using the method of ... microscopy.

Answer: email.

48. Ecology DOES NOT study ... the level of organization of life.

Answer: cellular.

49. The ability of biosystems to maintain a constant chemical composition and the intensity of biological processes is

Answer: self-regulation.

50. The scientific hypothesis that can explain the observed data is

Answer: hypothesis.

51. A cell is a structural, functional unit of living, a unit of growth and development - this is the position ... of the theory.

Answer: cellular.

52. Synthesis of ATP in animal cells occurs in

Answer: mitochondria.

53. The similarity of the cells of fungi and animals is that they have ... a way of feeding.

Answer: Heterotrophic.

54. The elementary structural, functional and genetic unit of the living is

Answer: a cage.

55. An elementary open living system is

Answer: a cage.

56. The elementary unit of reproduction and development is

Answer: a cage.

57. The cell wall in plants is formed

Answer: cellulose.

58. The concept of the unity of all living things is based on ... theory.

Answer: cellular.

59. The microscope for biological research invented

Answer: R. Hooke (Hooke).

60. The founder of microbiology is

Answer: L. Pasteur (Pasteur).

61. For the first time the term "cell" was used by

Answer: R. Hooke (Hooke).

62. Discovered single-celled organisms

Answer: A. Levenguk (Levenguk).

63. "All new cells are formed by dividing the original" - this position of modern cell theory proved

Answer: R. Virkhov.

64. M. Schleiden and T. Schwann formulated the main provisions ... of the theory.

Answer: cellular.

65. The reserve substance in bacterial cells is

Answer: murein.

66. "The cells of all organisms are similar in chemical composition, structure and functions" - this is the position ... of the theory.

Answer: cellular.

67. Bacteria, fungi, plants and animals consist of cells, therefore a cell is called a unit

Answer: buildings.

68. Cell walls DO NOT have cells

Answer: animals.

69. All eukaryotic organisms are characterized by the presence in cells

Answer: kernels.

70. Cellular structure do not have

Answer: viruses.

71. The nucleus in plant cells discovered

Answer: R. Brown (Brown).

72. In mushrooms, the storage carbohydrate is

Answer: glycogen.

Kirilenko A.A. Biology. Unified State Exam. Section "Molecular Biology". Theory, training tasks. 2017.

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1. What does anatomy study?

Human anatomy is the science of the shape, structure and development of the human body in accordance with gender, age and individual characteristics.

Anatomy studies the external forms and proportions of the human body and its parts, individual organs, their structure, microscopic structure. The tasks of anatomy include the study of the main stages of human development in the process of evolution, the structural features of the body and individual organs at different age periods, as well as in the external environment.

2. What does physiology study?

Physiology - (from the Greek physis - nature and logos - a word, doctrine), the science of life processes and the mechanisms of their regulation in the human body. Physiology studies the mechanisms of various functions of a living organism (growth, reproduction, respiration, etc.), their relationship with each other, regulation and adaptation to the external environment, origin and formation in the process of evolution and individual development of an individual. Solving fundamentally common problems, the physiology of animals and humans and the physiology of plants have differences due to the structure and functions of their objects. So, for the physiology of animals and humans, one of the main tasks is to study the regulating and integrating role of the nervous system in the body. Major physiologists (I.M.Sechenov, N.E. Vvedensky, I.P. Pavlov, A.A. For plant physiology, which emerged from botany in the 19th century, traditionally the study of mineral (root) and air (photosynthesis) nutrition, flowering, fruiting, etc. It serves as the theoretical basis of plant growing and agronomy. The founders of Russian plant physiology - A.S. Famintsyn and K.A. Timiryazev. Physiology is associated with anatomy, cytology, embryology, biochemistry, and other biological sciences.

3. What does hygiene study?

Hygiene - (from ancient Greek.? GeyinYu "healthy", from? Gyaib "health") - the science of the influence of the environment on human health.

As a result, hygiene has two objects of study - environmental factors and the body's reaction, and uses the knowledge and methods of physics, chemistry, biology, geography, hydrogeology, and other sciences that study the environment, as well as physiology, anatomy and pathophysiology.

Environmental factors are varied and are classified into:

Physical - noise, vibration, electromagnetic and radioactive radiation, climate, etc.

· Chemical - chemical elements and their compounds.

· Factors of human activity - the daily routine, the severity and intensity of labor, etc.

· Social.

Within the framework of hygiene, the following main sections are distinguished:

· Hygiene of the environment - studying the impact of natural factors - atmospheric air, solar radiation, etc.

· Occupational hygiene - studying the impact of the working environment and factors of the production process on a person.

· Communal hygiene - within the framework of which requirements are developed for urban planning, housing, water supply, etc.

· Food hygiene - studies the meaning and impact of food, develops measures to optimize and ensure food safety (this section is often confused with nutritional science).

· Hygiene of children and adolescents - studying the complex effect of factors on a growing organism.

· Military hygiene - aimed at maintaining and increasing the combat effectiveness of personnel.

· Personal hygiene - a set of hygienic rules, the implementation of which contributes to the preservation and strengthening of health.

Also, some narrow sections: radiation hygiene, industrial toxicology, etc.

The main tasks of hygiene:

· Study of the influence of the external environment on the state of health and performance of people. At the same time, the external environment should be understood as the whole complex complex of natural, social, household, production and other factors.

· Scientific substantiation and development of hygienic standards, rules and measures to improve the environment and eliminate harmful factors;

· Scientific substantiation and development of hygienic standards, rules and measures to increase the body's resistance to possible harmful environmental influences in order to improve health and physical development, increase efficiency. This is facilitated by rational nutrition, physical exercise, hardening, a properly organized work and rest regime, and adherence to the rules of personal hygiene.

4. What factors disturbing the balance between the environment and the body are toxins?

Each person's body contains a certain amount of harmful substances, which are called toxins (from the Greek toxikon - poison). They fall into two large groups.

Exotoxins are harmful substances of chemical and natural origin that enter the body from the external environment with food, air or water. Most often these are nitrates, nitrites, heavy metals and many other chemical compounds present in almost everything that surrounds us. Living in large industrial cities, working in hazardous industries and even taking drugs containing toxic substances - all these, to one degree or another, are factors of body poisoning.

Endotoxins are harmful substances that are formed during the life of the body. Especially a lot of them appear with various diseases and metabolic disorders, in particular, with poor bowel function, abnormal liver function, with angina, pharyngitis, influenza, acute respiratory infections, kidney diseases, allergic conditions, even stress.

Toxins poison the body and disrupt its well-coordinated work - most often they undermine the immune, hormonal, cardiovascular and metabolic systems. This leads to a complication of the course of various diseases and prevents recovery. Toxins lead to a decrease in the body's resistance, a deterioration in general condition and a breakdown.

One theory of aging suggests that it is caused by the accumulation of toxins in the body. They inhibit the work of organs, tissues, cells, disrupt the course of biochemical processes in them. This ultimately leads to a deterioration in their functions and, as a consequence, to aging of the whole organism.

Almost any disease is much easier and easier to treat if toxins do not accumulate and are quickly eliminated from the body.

Nature has endowed man with various systems and organs capable of destroying, neutralizing and removing harmful substances from the body. These are, in particular, the systems of the liver, kidneys, lungs, skin, gastrointestinal tract, etc. In modern conditions, it is becoming increasingly difficult to cope with aggressive toxins, and a person needs additional reliable and effective help.

5. What factors does radiation refer to?

Radioactivity is called the instability of the nuclei of some atoms, which manifests itself in their ability to spontaneously transform (according to scientific - decay), which is accompanied by the release of ionizing radiation (radiation). The energy of such radiation is large enough, therefore, it is capable of acting on matter, creating new ions of different signs. It is impossible to cause radiation by means of chemical reactions, it is a completely physical process.

There are several types of radiation:

· Alpha particles are relatively heavy particles, positively charged, are helium nuclei.

· Beta particles are ordinary electrons.

· Gamma radiation - has the same nature as visible light, but much more penetrating power.

· Neutrons are electrically neutral particles that arise mainly near a working nuclear reactor, access there must be limited.

· X-rays - Similar to gamma rays, but with lower energy. By the way, the Sun is one of the natural sources of such rays, but the Earth's atmosphere provides protection from solar radiation.

Sources of radiation are nuclear technical installations (particle accelerators, reactors, X-ray equipment) and radioactive substances. They can exist for a considerable time, without manifesting themselves in any way, and you may not even suspect that you are near the object of the strongest radioactivity.

The body reacts to the radiation itself, not to its source. Radioactive substances can enter the body through the intestines (with food and water), through the lungs (during breathing) and even through the skin during medical diagnostics with radioisotopes. In this case, internal irradiation takes place. In addition, external radiation exerts a significant effect of radiation on the human body, i.e. the source of radiation is outside the body. Internal irradiation is certainly the most dangerous.

The impact of radiation on the human body is called radiation. During this process, radiation energy is transferred to cells, destroying them. Irradiation can cause all kinds of diseases: infectious complications, metabolic disorders, malignant tumors and leukemia, infertility, cataracts and much more. Radiation is especially acute for dividing cells, so it is especially dangerous for children.

Radiation refers to those factors of physiological impact on the human body, for the perception of which it does not have receptors. He is simply unable to see, hear, or feel it to the touch or taste.

The absence of direct cause-and-effect relationships between radiation and the body's response to its effect allows us to constantly and quite successfully exploit the idea of the danger of the effect of small doses on human health.

6. What factors are viruses?

Viruses (derived from the Latin virus - "poison") are the smallest microorganisms that do not have a cellular structure, protein-synthesizing system and are capable of reproducing only in the cells of highly organized forms of life. To designate an agent capable of causing an infectious disease, it was first used in 1728.

The appearance of viruses on the evolutionary tree of life is unclear: some of them may have formed from plasmids, small DNA molecules that can be passed from one cell to another, while others may have originated from bacteria. In evolution, viruses are an important means of horizontal gene transfer, leading to genetic diversity.

Viruses spread in many ways: plant viruses are often transmitted from plant to plant by insects that feed on plant sap, such as aphids; animal viruses can be spread by blood-sucking insects, such organisms are known as vectors. The influenza virus is spread by airborne droplets through coughing and sneezing. Norovirus and rotavirus, which commonly cause viral gastroenteritis, are transmitted by the faecal-oral route through contact with contaminated food or water. HIV is one of several sexually transmitted viruses and blood transfusions. Each virus has a specific host specificity based on the types of cells it can infect. The host range can be narrow or, if the virus infects many species, wide.

Viruses, although very small, cannot be seen, are the object of study of the sciences:

For a physician, viruses are the most frequent causative agents of infectious diseases: influenza, measles, smallpox, tropical fevers.

For a pathologist, viruses are the etiological agents (cause) of cancer and leukemia, the most frequent and dangerous pathological processes.

For a veterinarian, viruses are the culprits of epizootics (mass diseases) of foot and mouth disease, bird plague, infectious anemia and other diseases affecting farm animals.

For an agronomist, viruses are the causative agents of spotted stripes in wheat, tobacco mosaic, yellow dwarfism of potatoes and other diseases of agricultural plants.

For the grower, viruses are the factors that cause the appearance of amazing tulip colors.

For the medical microbiologist, viruses are agents that cause the appearance of toxic (poisonous) varieties of diphtheria or other bacteria, or factors that contribute to the development of bacteria resistant to antibiotics.

For the industrial microbiologist, viruses are pests of bacteria, producers, antibiotics and enzymes.

For a geneticist, viruses are carriers of genetic information.

For a Darwinist, viruses are important factors in the evolution of the organic world.

For an ecologist, viruses are factors involved in the formation of conjugated systems of the organic world.

For a biologist, viruses are the simplest forms of life, possessing all of its main manifestations.

For a philosopher, viruses are the clearest illustration of the dialectics of nature, a touchstone for polishing concepts such as living and nonliving, part and whole, form and function.

Viruses are the causative agents of the most important diseases of humans, farm animals and plants, and their importance is increasing all the time as the incidence of bacterial, protozoal and fungal diseases decreases.

7. What is homeostasis?

Life is possible only with a relatively small range of deviations of various characteristics of the internal environment - physicochemical (acidity, osmotic pressure, temperature, etc.) and physiological (blood pressure, blood sugar, etc.) - from a certain average value. The constancy of the internal environment of a living organism is called homeostasis (from the Greek words homoios - similar, identical and stasis - state).

Under the influence of environmental factors, the vital characteristics of the internal environment can change. Then in the body there are reactions aimed at their restoration or prevention of such changes. These reactions are called homeostatic. When blood is lost, for example, vasoconstriction occurs, preventing a drop in blood pressure. As the consumption of sugar increases during physical work, its release into the blood from the liver increases, which prevents a drop in blood sugar levels. With an increase in heat production in the body, the skin vessels expand, and therefore heat transfer increases, which prevents the body from overheating.

Homeostatic reactions are organized by the central nervous system, which regulates the activity of the autonomic and endocrine systems. The latter already directly affect the tone of the blood vessels, the intensity of metabolism, the work of the heart and other organs. The mechanisms of the same homeostatic reaction and their effectiveness can be different and depend on many factors, including hereditary ones.

Homeostasis is also called the preservation of the constancy of the species composition and the number of individuals in biocenoses, the ability of a population to maintain a dynamic balance of the genetic composition, which ensures its maximum viability (genetic homeostasis).

8. What is cytolemma?

Cytolemma is a universal cell skin that performs barrier, protective, receptor, excretory functions, transfers nutrients, transmits nerve impulses and hormones, connects cells to tissues.

It is the thickest (10 nm) and complexly organized cell membrane. It is based on a universal biological membrane, covered from the outside by a glycocalyx, and from the inside, from the side of the cytoplasm, by a submembrane layer. Glycocalyx (3-4 nm thick) is represented by the outer, carbohydrate regions of complex proteins - glycoproteins and glycolipids that make up the membrane. These carbohydrate chains play the role of receptors that ensure recognition by the cell of neighboring cells and intercellular substance and interaction with them. This layer also includes surface and semi-integral proteins, the functional areas of which are located in the supramembrane zone (for example, immunoglobulins). The glycocalyx contains receptors for histocompatibility, receptors for many hormones and neurotransmitters.

The submembrane cortical layer is formed by microtubules, microfibrils and contractile microfilaments, which are part of the cytoskeleton of the cell. The submembrane layer maintains the shape of the cell, creates its elasticity, and ensures changes in the cell surface. Due to this, the cell participates in endo- and exocytosis, secretion, and movement.

Cytolemma performs many functions:

1) delimiting (cytolemma separates, delimits the cell from the environment and ensures its connection with the external environment);

2) recognition by a given cell of other cells and attachment to them;

3) recognition by the cell of the intercellular substance and attachment to its elements (fibers, basement membrane);

4) transport of substances and particles into and out of the cytoplasm;

5) interaction with signaling molecules (hormones, mediators, cytokines) due to the presence of specific receptors on its surface;

6) ensures the movement of the cell (the formation of pseudopodia) due to the connection of the cytolemma with the contractile elements of the cytoskeleton.

The cytolemma contains numerous receptors through which biologically active substances (ligands, signaling molecules, the first mediators: hormones, mediators, growth factors) act on the cell. Receptors are genetically determined macromolecular sensors (proteins, glyco- and lipoproteins) built into the cytolemma or located inside the cell and specialized for the perception of specific signals of a chemical or physical nature. When biologically active substances interact with the receptor, they cause a cascade of biochemical changes in the cell, transforming at the same time into a specific physiological response (change in cell function).

All receptors have a common structure plan and consist of three parts: 1) overmembrane, which interacts with a substance (ligand); 2) intramembrane, carrying out signal transfer and 3) intracellular, immersed in the cytoplasm.

9. How important is the kernel?

The nucleus is an essential component of the cell (exception: mature erythrocytes), where the bulk of the DNA is concentrated.

There are two important processes in the nucleus. The first of them is the synthesis of the genetic material itself, during which the amount of DNA in the nucleus doubles (for DNA and RNA, see Nucleic acids). This process is necessary so that during subsequent cell division (mitosis), the two daughter cells have the same amount of genetic material. The second process is transcription - the production of all types of RNA molecules, which, migrating into the cytoplasm, provide the synthesis of proteins necessary for the life of the cell.

The nucleus differs from the surrounding cytoplasm in terms of the refractive index of light. That is why it can be seen in a living cell, but usually special dyes are used to identify and study the nucleus. The Russian name "nucleus" reflects the spherical shape most characteristic of this organoid. Such nuclei can be seen in liver cells, nerve cells, but in smooth muscle and epithelial cells, the nucleus is oval. There are nuclei of more bizarre shapes.

The most dissimilar cores consist of the same components, i.e. have a general building plan. In the nucleus, there are: the nuclear envelope, chromatin (chromosomal material), the nucleolus and the nuclear juice. Each nuclear component has its own structure, composition and function.

The nuclear envelope includes two membranes located at some distance from each other. The space between the membranes of the nuclear envelope is called perinuclear. There are holes in the nuclear envelope - pores. But they are not end-to-end, but filled with special protein structures, which are called the nuclear pore complex. Through the pores, RNA molecules leave the nucleus into the cytoplasm, and proteins move towards them into the nucleus. The membranes of the nuclear envelope themselves provide for the diffusion of low molecular weight compounds in both directions.

Chromatin (from the Greek word chroma - color, paint) is a substance of chromosomes, which in the interphase nucleus are much less compact than during mitosis. When cells are stained, they are brighter than other structures.

The nucleolus is clearly visible in the nuclei of living cells. It has the appearance of a rounded or irregular body and stands out clearly against the background of a fairly uniform nucleus. The nucleolus is a formation that occurs in the nucleus on those chromosomes that are involved in the synthesis of ribosome RNA. The region of the chromosome that forms the nucleolus is called the nucleolar organizer. In the nucleolus, not only RNA synthesis occurs, but also the assembly of ribosome subparticles. The number of nucleoli and their sizes may vary. The products of chromatin and nucleolus activity enter the nuclear juice (karyoplasm) initially.

For the growth and reproduction of cells, the nucleus is absolutely necessary. If the main part of the cytoplasm is experimentally separated from the nucleus, then this cytoplasmic lump (cytoplast) can exist without a nucleus for only a few days. The nucleus, surrounded by the narrowest rim of the cytoplasm (karyoplast), fully retains its viability, gradually ensuring the restoration of organelles and the normal volume of the cytoplasm. Nevertheless, some specialized cells, such as mammalian erythrocytes, function for a long time without a nucleus. It is also lacking in platelets - platelets formed as fragments of the cytoplasm of large cells - megakaryocytes. Sperm have a nucleus, but it is completely inactive.

10. What is fertilization?

Fertilization is the fusion of a male reproductive cell (sperm) with a female (egg), leading to the formation of a zygote, which gives rise to a new organism. Fertilization is preceded by complex processes of maturation of the egg (oogenesis) and sperm (spermatogenesis). Unlike sperm, the egg does not have independent mobility. A mature egg leaves the follicle into the abdominal cavity in the middle of the menstrual cycle at the time of ovulation and enters the fallopian tube due to its suction peristaltic movements and cilia flickering. The period of ovulation and the first 12-24 hours. after it are most favorable for fertilization. If it did not happen, then in the following days regression and death of the egg occur.

During sexual intercourse, semen (seminal fluid) enters the woman's vagina. Under the influence of the acidic environment of the vagina, some of the sperm die. The most viable of them penetrate through the cervical canal into the alkaline medium of its cavity and, 1.5-2 hours after intercourse, reach the fallopian tubes, in the ampullar section of which fertilization takes place. Many spermatozoa rush to a mature egg, but, as a rule, only one of them penetrates through the shiny membrane covering it, the nucleus of which merges with the nucleus of the egg. From the moment of the fusion of the germ cells, pregnancy begins. A single-celled embryo is formed, a qualitatively new cell - a zygote, from which the human body is formed as a result of a complex developmental process during pregnancy. The sex of the unborn child depends on what type of sperm the egg was fertilized, which is always the carrier of the X chromosome. In the event that an egg has been fertilized by a sperm with an X (female) sex chromosome, a female embryo (XX) occurs. When an egg is fertilized by a sperm with a Y (male) sex chromosome, a male embryo (XY) develops. There is evidence that spermatozoa containing the Y chromosome are less durable and die faster than spermatozoa containing the X chromosome. Obviously, in this regard, the likelihood of conceiving a boy increases if the fertilizing intercourse occurred during ovulation. In the event that sexual intercourse was a few days before ovulation, there is a greater chance that fertilization will occur. The eggs are sperm containing the X chromosome, that is, the probability of having a girl is higher.

The fertilized egg, moving along the fallopian tube, undergoes crushing, goes through the stages of blastula, morula, blastocyst and reaches the uterine cavity on the 5-6th day from the moment of fertilization. At this point, the embryo (embryoblast) is covered on the outside with a layer of special cells - trophoblast, which provides nutrition and implantation (introduction) of it into the uterine mucosa, which is called decidual during pregnancy. The trophoblast secretes enzymes that dissolve the lining of the uterus, which facilitates the immersion of the fertilized egg into its thickness.

11. What characterizes the crushing stage?

Cleavage is a series of rapid zygote divisions without intermediate growth.

After combining the genomes of the egg and sperm, the zygote immediately begins mitotic division - the development of a multicellular diploid organism begins. The first stage of this development is called fragmentation. It has a number of features. First of all, in most cases, cell division does not alternate with cell growth. The number of cells of the embryo increases, and its total volume remains approximately equal to the volume of the zygote. During cleavage, the volume of the cytoplasm remains approximately constant, while the number of nuclei, their total volume, and in particular the surface area, increase. This means that during the cleavage period, normal (i.e., characteristic of somatic cells) nuclear-plasma relations are restored. Mitoses during cleavage especially quickly follow one another. This is due to the contraction of the interphase: the Gx period drops out completely, the G2 period also decreases. The interphase is practically reduced to the S-period: as soon as the entire DNA doubles, the cell enters into mitosis.

The cells that form during cleavage are called blastomeres. In many animals, they divide synchronously for quite a long time. True, sometimes this synchronicity breaks down early: for example, in roundworms at the stage of four blastomeres, and in mammals, the first two blastomeres divide asynchronously. In this case, the first two divisions usually occur in the meridian planes (pass through the animal-vegetative axis), and the third division - in the equatorial (perpendicular to this axis).

Another characteristic feature of cleavage is the absence of signs of tissue differentiation in blastomeres. Cells may already "know" their future fate, but they do not yet have signs of nerve, muscle or epithelial.

12. What is implantation?

physiology cytolemma zygote

Implantation (from Lat. In (im) - in, inside and plantatio - planting, transplantation), attachment of the embryo to the wall of the uterus in mammals with intrauterine development and in humans.

There are three types of implantation:

· Central implantation - when the embryo remains in the lumen of the uterus, attaching itself to its wall either with the entire surface of the trophoblast, or only with its part (in bats, ruminants).

Eccentric implantation - the embryo penetrates deep into the folds of the uterine mucosa (the so-called uterine crypt), the walls of which then grow together over the embryo and form an implantation chamber isolated from the uterine cavity (in rodents).

· Interstitial implantation - typical for higher mammals (primates and humans) - the embryo actively destroys the cells of the uterine mucosa and penetrates into the formed cavity; the defect of the uterus heals, and the embryo is completely immersed in the wall of the uterus, where its further development takes place.

13. What is gastrulation?

Gastrulation is a complex process of morphogenetic changes, accompanied by reproduction, growth, directed movement and differentiation of cells, resulting in the formation of germ layers (ectoderm, mesoderm and endoderm) - sources of tissue and organ rudiments. The second stage of ontogenesis after crushing. During gastrulation, the movement of cell masses occurs with the formation of a two-layer or three-layer embryo from the blastula - gastrula.

The type of blastula determines the mode of gastrulation.

The embryo at this stage consists of clearly separated layers of cells - germ layers: external (ectoderm) and internal (endoderm).

In multicellular animals, except for coelenterates, in parallel with gastrulation or, like in a lancelet, a third germ layer, the mesoderm, appears after it, which is a collection of cellular elements located between the ectoderm and endoderm. Due to the appearance of the mesoderm, the embryo becomes three-layered.

In many groups of animals, it is at the stage of gastrulation that the first signs of differentiation appear. Differentiation (differentiation) - the process of the emergence and growth of structural and functional differences between individual cells and parts of the embryo.

The nervous system, sensory organs, skin epithelium, tooth enamel are formed from the ectoderm; from the endoderm - the epithelium of the midgut, digestive glands, epithelium of the gills and lungs; from the mesoderm - muscle tissue, connective tissue, circulatory system, kidneys, sex glands, etc.

In different groups of animals, the same germ layers give rise to the same organs and tissues.

Gastrulation methods:

· Intussusception - occurs by invagination of the blastula wall into the blastocoel; typical for most groups of animals.

· Delamination (typical for coelenterates) - the cells outside are transformed into the epithelial layer of the ectoderm, and the endoderm is formed from the remaining cells. Usually delamination is accompanied by divisions of blastula cells, the plane of which runs "tangentially" to the surface.

· Immigration - migration of individual cells of the blastula wall into the blastocoel.

· Unipolar - in one area of the blastula wall, usually at the vegetative pole;

· Multipolar - in several areas of the blastula wall.

· Epibolia - overgrowth of some cells by rapidly dividing other cells or overgrowth of cells of the inner mass of the yolk (with incomplete cleavage).

· Involution - the screwing inside the embryo of an enlarging outer layer of cells, which spreads along the inner surface of the cells remaining outside.

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Apricot

APRICOT, genus of trees and shrubs of this. rosaceae. Includes 10 species, wildly growing mainly in Asia. In culture, more than 5 thousand years. Mainly common apricot is grown. Tree height up to 8 m, durable, light-requiring, heat-resistant, for ...

Avicenna

Avocado

AVOCADO (American Perseus), evergreen tree of this. laurel, fruit crop. Homeland - Central and South America, where it has been grown for a long time. It is also cultivated in Australia, Cuba. In Russia - on the Black Sea coast of the Caucasus. Trunk in ...

Australian echidna

AUSTRALIAN ECHIDNA, mammal of the family. echidnova neg. monotremes (oviparous). Lives in Eastern Australia and on its western tip. L. bodies approx. 40 cm, weight 2.5–6 kg. The body is covered with thick long needles. 6-8 cm. The most powerful needles are located ...

Australopithecus

AUSTRALOPITEKOVYE, fossil representatives of neg. primates, walking on two legs. They have common features both with monkeys (for example, the primitive structure of the skull) and with humans (for example, a more developed brain than a monkey, upright posture). V...

Autotrophs

AUTOTROPHES, organisms that synthesize the organic substances they need from inorganic compounds. Autotrophs include terrestrial green plants (they form organic matter from carbon dioxide and water in the process of photosynthesis), algae, ...

Agave

AGAVA, a genus of perennial plants of the family. agave. Includes St. 300 kinds. Homeland - Central America and the Caribbean islands. Succulents. Many species (American agave, drawn, etc.) are grown as indoor plants. Stems are short silt ...

Adaptation

ADAPTATION, adaptation of an organism, population or biological species to environmental conditions. Includes morphological, physiological, behavioral, and other changes (or their combination) that ensure survival in these conditions. Adaptations ...

Adenosine triphosphate

ADENOSINTRIPHOSPHATE (ATP), nucleotide, universal accumulator and carrier of chemical energy in living cells. The ATP molecule consists of the nitrogenous base of adenine, the carbohydrate ribose, and three residues of phosphoric acid (phosphates). Chemical energy of ATP ...

Adenoids

Adenoids, an increase in the pharyngeal (nasopharyngeal) tonsil due to the proliferation of its lymphoid tissue. The reasons are allergies, childhood infections. Adenoids cause impaired nasal breathing, hearing loss, nasal voice. Often attached ...

Everything you need to know about the OGE in biology in 2019 can be read - how to prepare, what to look for, why they can remove points, which is advised by the participants in the OGE last year.

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Biology(from the Greek. bios- life, logos- word, science) is a complex of sciences about living nature.

The subject of biology is all manifestations of life: the structure and functions of living beings, their diversity, origin and development, as well as interaction with the environment. The main task of biology as a science is to interpret all phenomena of living nature on a scientific basis, taking into account that an integral organism has properties that are fundamentally different from its components.

The term "biology" is found in the works of the German anatomists T. Roose (1779) and K. F. Burdach (1800), but it was not until 1802 that it was first used independently by J. B. Lamarcom and G. R. Treviranus to denote a science that studies living organisms.

Biological sciences

At present, biology includes a number of sciences that can be systematized according to the following criteria: according to the subject and prevailing research methods and according to the studied level of organization of living nature. According to the subject of research, biological sciences are divided into bacteriology, botany, virology, zoology, mycology.

Botany is a biological science that comprehensively studies the plants and vegetation of the Earth. Zoology- the section of biology, the science of diversity, structure, life, distribution and relationship of animals with the habitat, their origin and development. Bacteriology- biological science, which studies the structure and life of bacteria, as well as their role in nature. Virology- biological science that studies viruses. The main object of mycology is fungi, their structure and features of life. Lichenology- a biological science that studies lichens. Bacteriology, virology and some aspects of mycology are often considered as part of microbiology - the section of biology, the science of microorganisms (bacteria, viruses and microscopic fungi). Taxonomy, or taxonomy, is a biological science that describes and classifies all living and extinct creatures into groups.

In turn, each of the listed biological sciences is subdivided into biochemistry, morphology, anatomy, physiology, embryology, genetics and taxonomy (of plants, animals or microorganisms). Biochemistry- is the science of the chemical composition of living matter, chemical processes occurring in living organisms and underlying their life. Morphology- biological science, which studies the shape and structure of organisms, as well as the laws of their development. In a broad sense, it includes cytology, anatomy, histology and embryology. Distinguish between the morphology of animals and plants. Anatomy is a branch of biology (more precisely, morphology), a science that studies the internal structure and shape of individual organs, systems and the organism as a whole. Plant anatomy is considered as part of botany, animal anatomy as part of zoology, and human anatomy is a separate science. Physiology- biological science, which studies the vital processes of plant and animal organisms, their individual systems, organs, tissues and cells. There is a physiology of plants, animals and humans. Embryology (developmental biology)- the section of biology, the science of the individual development of the organism, including the development of the embryo.

Object genetics are the patterns of heredity and variability. It is currently one of the most dynamically developing biological sciences.

According to the studied level of organization of living nature, molecular biology, cytology, histology, organology, biology of organisms and supraorganism systems are distinguished. Molecular biology is one of the youngest branches of biology, a science that studies, in particular, the organization of hereditary information and protein biosynthesis. Cytology, or cell biology, is a biological science, the object of study of which is the cells of both unicellular and multicellular organisms. Histology- biological science, a section of morphology, the object of which is the structure of tissues of plants and animals. The sphere of organology includes the morphology, anatomy and physiology of various organs and their systems.

Biology of organisms includes all sciences, the subject of which is living organisms, for example, ethology- the science of the behavior of organisms.

The biology of supraorganism systems is subdivided into biogeography and ecology. The distribution of living organisms studies biogeography, whereas ecology- organization and functioning of supraorganism systems of various levels: populations, biocenoses (communities), biogeocenoses (ecosystems) and biosphere.

According to the prevailing research methods, descriptive (for example, morphology), experimental (for example, physiology) and theoretical biology can be distinguished.

Revealing and explaining the patterns of structure, functioning and development of living nature at various levels of its organization is a task general biology... It includes biochemistry, molecular biology, cytology, embryology, genetics, ecology, evolutionary doctrine and anthropology. Evolutionary doctrine studies the causes, driving forces, mechanisms and general laws of the evolution of living organisms. One of its sections is paleontology- science, the subject of which is the fossil remains of living organisms. Anthropology- a section of general biology, the science of the origin and development of man as a biological species, as well as the diversity of populations of modern man and the laws of their interaction.

The applied aspects of biology are classified in the field of biotechnology, breeding, and other rapidly developing sciences. Biotechnology is called the biological science that studies the use of living organisms and biological processes in production. It is widely used in food (bakery, cheese making, brewing, etc.) and pharmaceutical industries (obtaining antibiotics, vitamins), for water purification, etc. Selection- the science of methods of creating breeds of domestic animals, varieties of cultivated plants and strains of microorganisms with the properties that a person needs. Selection is understood as the very process of changing living organisms, carried out by a person for his needs.

The progress of biology is closely related to the success of other natural and exact sciences, such as physics, chemistry, mathematics, computer science, etc. For example, microscopy, ultrasound examinations (ultrasound), tomography and other methods of biology are based on physical laws, and processes occurring in living systems would be impossible without the use of chemical and physical methods. The use of mathematical methods allows, on the one hand, to reveal the presence of a regular connection between objects or phenomena, to confirm the reliability of the results obtained, and on the other hand, to simulate a phenomenon or process. Recently, computer methods, for example, modeling, have become increasingly important in biology. At the junction of biology and other sciences, a number of new sciences have arisen, such as biophysics, biochemistry, bionics, etc.

Advances in biology

The most important events in the field of biology, which influenced the entire course of its further development, are: the establishment of the molecular structure of DNA and its role in the transmission of information in living matter (F. Crick, J. Watson, M. Wilkins); decoding of the genetic code (R. Holly, H. G. Korana, M. Nirenberg); discovery of the gene structure and genetic regulation of protein synthesis (A. M. Lvov, F. Jacob, J. L. Monod and others); cell theory formulation (M. Schleiden, T. Schwann, R. Virchow, K. Baer); study of the laws of heredity and variability (G. Mendel, H. de Vries, T. Morgan and others); the formulation of the principles of modern taxonomy (K. Linnaeus), evolutionary theory (C. Darwin) and the doctrine of the biosphere (V. I. Vernadsky).

The significance of the discoveries of recent decades has yet to be assessed, but the most significant achievements of biology were recognized: decoding the genome of humans and other organisms, determining the mechanisms for controlling the flow of genetic information in the cell and the developing organism, mechanisms for regulating cell division and death, cloning mammals, and the discovery of pathogens " mad cow disease ”(prions).

The work on the Human Genome program, which was carried out simultaneously in several countries and was completed at the beginning of this century, led us to the understanding that a person has about 25-30 thousand genes, but information from most of our DNA is never read , since it contains a huge number of areas and genes encoding traits that have lost their meaning for humans (tail, body hair, etc.). In addition, a number of genes were deciphered that are responsible for the development of hereditary diseases, as well as genes for drug targets. However, the practical application of the results obtained during the implementation of this program is postponed until the genomes of a significant number of people have been deciphered, and then it becomes clear what the difference is. These goals have been set for a number of leading laboratories around the world working on the implementation of the ENCODE program.

Biological research is the foundation of medicine, pharmacy, and is widely used in agriculture and forestry, food industry and other branches of human activity.

It is well known that only the “green revolution” of the 1950s made it possible to at least partially solve the problem of providing the rapidly growing population of the Earth with food, and animal husbandry - with fodder through the introduction of new varieties of plants and progressive technologies for their cultivation. Due to the fact that the genetically programmed properties of agricultural crops are almost exhausted, the further solution of the food problem is associated with the widespread introduction of genetically modified organisms into production.

The production of many food products, such as cheeses, yoghurts, sausages, baked goods, etc., is also impossible without the use of bacteria and fungi, which is the subject of biotechnology.

Knowledge of the nature of pathogens, the processes of the course of many diseases, the mechanisms of immunity, the patterns of heredity and variability have made it possible to significantly reduce mortality and even completely eradicate a number of diseases, such as smallpox. With the help of the latest achievements of biological science, the problem of human reproduction is also being solved.

A significant part of modern medicines are made on the basis of natural raw materials, as well as thanks to the success of genetic engineering, such as insulin, which is so necessary for patients with diabetes mellitus, is mainly synthesized by bacteria that have transferred the corresponding gene.

Biological research is no less important for the preservation of the environment and the diversity of living organisms, the threat of extinction of which casts doubt on the existence of mankind.

Of the greatest importance among the achievements of biology is the fact that they even underlie the construction of neural networks and genetic code in computer technology, and are also widely used in architecture and other industries. There is no doubt that the 21st century is the century of biology.

Methods of cognition of living nature

Like any other science, biology has its own arsenal of methods. In addition to the scientific method of cognition used in other fields, such methods as historical, comparative-descriptive, etc. are widely used in biology.

The scientific method of cognition includes observation, formulation of hypotheses, experiment, modeling, analysis of results and derivation of general patterns.

Observation- this is the purposeful perception of objects and phenomena with the help of the senses or devices, conditioned by the task of the activity. The main condition for scientific observation is its objectivity, that is, the ability to verify the data obtained by repeated observation or the use of other research methods, for example, experiment. The facts obtained as a result of observation are called data... They can be like quality(describing smell, taste, color, shape, etc.), and quantitative and quantitative data are more accurate than qualitative.

Based on the observational data, it is formulated hypothesis- a presumptive judgment about the natural connection of phenomena. The hypothesis is tested in a series of experiments. Experiment is called a scientifically established experience, the observation of the phenomenon under study in controlled conditions, which makes it possible to identify the characteristics of a given object or phenomenon. The highest form of experiment is modeling- study of any phenomena, processes or systems of objects by building and studying their models. In essence, this is one of the main categories of the theory of knowledge: any method of scientific research, both theoretical and experimental, is based on the idea of modeling.

Experimental and simulation results are thoroughly analyzed. Analysis is called the method of scientific research by decomposing an object into its component parts or mentally dismembering an object by logical abstraction. Analysis is inextricably linked with synthesis. Synthesis is a method of studying a subject in its integrity, in the unity and interconnection of its parts. As a result of analysis and synthesis, the most successful research hypothesis becomes working hypothesis, and if it can resist attempts to refute it and still successfully predicts previously unexplained facts and relationships, then it can become a theory.

Under theory understand a form of scientific knowledge that gives a holistic view of the laws and essential connections of reality. The general direction of scientific research is to achieve higher levels of predictability. If the theory cannot be changed by any facts, and the encountered deviations from it are regular and predictable, then it can be raised to the rank of the law- a necessary, essential, stable, repetitive relationship between phenomena in nature.

As the body of knowledge grows and research methods improve, hypotheses and deeply rooted theories can be challenged, modified and even rejected, since scientific knowledge itself is dynamic in nature and is constantly undergoing critical rethinking.

Historical method reveals the patterns of the appearance and development of organisms, the formation of their structure and function. In some cases, with the help of this method, hypotheses and theories that were previously considered false are gaining new life. This, for example, happened with Charles Darwin's assumptions about the nature of signal transmission through a plant in response to environmental influences.

Comparative-descriptive method provides for anatomical and morphological analysis of research objects. It underlies the classification of organisms, identifying the patterns of the emergence and development of various forms of life.

Monitoring is a system of measures for monitoring, assessing and predicting changes in the state of the object under study, in particular the biosphere.

Observations and experiments often require the use of special equipment, such as microscopes, centrifuges, spectrophotometers, etc.

Microscopy is widely used in zoology, botany, human anatomy, histology, cytology, genetics, embryology, paleontology, ecology and other branches of biology. It allows you to study the fine structure of objects using light, electron, X-ray and other types of microscopes.

Organism is an integral system capable of independent existence. According to the number of cells that make up organisms, they are divided into unicellular and multicellular. The cellular level of organization in unicellular organisms (common amoeba, green euglena, etc.) coincides with the organismal level. There was a period in the history of the Earth when all organisms were represented only by unicellular forms, but they ensured the functioning of both biogeocenoses and the biosphere as a whole. Most multicellular organisms are represented by a set of tissues and organs, which in turn also have a cellular structure. Organs and tissues are adapted to perform certain functions. The elementary unit of this level is an individual in its individual development, or ontogenesis, therefore, the organismic level is also called ontogenetic... An elementary phenomenon of this level is changes in the organism in its individual development.

Population-specific level

Population is a set of individuals of the same species, freely interbreeding with each other and living apart from other similar groups of individuals.

In populations, there is a free exchange of hereditary information and its transmission to descendants. The population is an elementary unit of the population-species level, and the elementary phenomenon in this case is evolutionary transformations, for example, mutations and natural selection.

Biogeocenotic level

Biogeocenosis is a historically established community of populations of different species, interconnected with each other and the environment by metabolism and energy.

Biogeocenoses are elementary systems in which the material-energy cycle is carried out, due to the vital activity of organisms. Biogeocenoses themselves are elementary units of a given level, while elementary phenomena are energy flows and cycles of substances in them. Biogeocenoses make up the biosphere and determine all the processes that take place in it.

Biosphere level

Biosphere- the shell of the Earth, inhabited by living organisms and transformed by them.

The biosphere is the highest level of organization of life on the planet. This shell covers the lower atmosphere, the hydrosphere, and the upper layer of the lithosphere. The biosphere, like all other biological systems, is dynamic and actively transformed by living beings. It is itself an elementary unit of the biosphere level, and the processes of the circulation of substances and energy that occur with the participation of living organisms are considered as an elementary phenomenon.

As mentioned above, each of the levels of organization of living matter contributes to a single evolutionary process: in the cell, not only the inherent hereditary information is reproduced, but also changes in it, which leads to the emergence of new combinations of signs and properties of the organism, which in turn undergo the action of natural selection at the population-species level, etc.

Biological systems

Biological objects of varying degrees of complexity (cells, organisms, populations and species, biogeocenoses and the biosphere itself) are currently considered as biological systems.

A system is a unity of structural components, the interaction of which gives rise to new properties in comparison with their mechanical totality. Thus, organisms are made up of organs, organs are formed by tissues, and tissues are formed by cells.

The characteristic features of biological systems are their integrity, the level principle of organization, as mentioned above, and openness. The integrity of biological systems is largely achieved through self-regulation, which functions according to the principle of feedback.

TO open systems refers to systems between which and the environment there is an exchange of substances, energy and information, for example, plants in the process of photosynthesis capture sunlight and absorb water and carbon dioxide, releasing oxygen.

One of the fundamental concepts in modern biology is the idea that all living organisms have a cellular structure. Science is engaged in the study of the structure of the cell, its vital activity and interaction with the environment. cytology, now more commonly referred to as cell biology. Cytology owes its appearance to the formulation of the cell theory (1838–1839, M. Schleiden, T. Schwann, supplemented in 1855 by R. Virkhov).

Cell theory is a generalized idea of the structure and functions of cells as living units, their reproduction and role in the formation of multicellular organisms.

The main provisions of the cell theory:

A cell is a unit of structure, vital activity, growth and development of living organisms - there is no life outside the cell. A cell is a single system consisting of many elements that are naturally connected with each other, which represent a certain integral formation. The cells of all organisms are similar in their chemical composition, structure and functions. New cells are formed only as a result of the division of mother cells ("cell from cell"). The cells of multicellular organisms form tissues, organs are composed of tissues. The life of an organism as a whole is determined by the interaction of its constituent cells. The cells of multicellular organisms have a complete set of genes, but differ from each other in that they have different groups of genes, which results in the morphological and functional diversity of cells - differentiation.

Thanks to the creation of the cell theory, it became clear that the cell is the smallest unit of life, an elementary living system, which has all the signs and properties of a living thing. The formulation of the cell theory became the most important prerequisite for the development of views on heredity and variability, since the identification of their nature and their inherent patterns inevitably suggested the universality of the structure of living organisms. Revealing the unity of the chemical composition and the structure of cells served as an impetus for the development of ideas about the origin of living organisms and their evolution. In addition, the origin of multicellular organisms from a single cell in the process of embryonic development has become a dogma of modern embryology.

In living organisms, there are about 80 chemical elements, but only 27 of these elements have been established for their functions in the cell and the body. The rest of the elements are present in small quantities, and, apparently, enter the body with food, water and air. The content of chemical elements in the body varies significantly. Depending on their concentration, they are divided into macronutrients and microelements.

The concentration of each macronutrients in the body exceeds 0.01%, and their total content is 99%. Macronutrients include oxygen, carbon, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium, sodium, chlorine, magnesium and iron. The first four of the listed elements (oxygen, carbon, hydrogen and nitrogen) are also called organogenic, since they are part of the main organic compounds. Phosphorus and sulfur are also components of a number of organic substances, such as proteins and nucleic acids. Phosphorus is essential for the formation of bones and teeth.

Normal functioning of the body is impossible without the remaining macronutrients. So, potassium, sodium and chlorine are involved in the processes of cell excitation. Potassium is also needed for many enzymes to function and water retention in the cell. Calcium is found in the cell walls of plants, bones, teeth and shells of molluscs and is required for muscle cell contraction and intracellular movement. Magnesium is a component of chlorophyll, a pigment that ensures photosynthesis. It also takes part in protein biosynthesis. Iron, in addition to being a part of hemoglobin, which carries oxygen in the blood, is necessary for the processes of respiration and photosynthesis, as well as for the functioning of many enzymes.

Trace elements are contained in the body in concentrations less than 0.01%, and their total concentration in the cell does not even reach 0.1%. Trace elements include zinc, copper, manganese, cobalt, iodine, fluorine, etc. Zinc is part of the pancreatic hormone insulin, copper is required for photosynthesis and respiration. Cobalt is a component of vitamin B12, the absence of which leads to anemia. Iodine is necessary for the synthesis of thyroid hormones, which ensure the normal course of metabolism, and fluoride is associated with the formation of tooth enamel.

Both a deficiency and an excess or impairment of the metabolism of macro- and microelements lead to the development of various diseases. In particular, a lack of calcium and phosphorus causes rickets, a lack of nitrogen - severe protein deficiency, iron deficiency - anemia, and lack of iodine - a violation of the formation of thyroid hormones and a decrease in metabolic rate. A decrease in the intake of fluoride with water and food largely determines the violation of the renewal of tooth enamel and, as a result, a predisposition to caries. Lead is toxic to almost all organisms. Its excess causes irreversible damage to the brain and central nervous system, which is manifested by loss of vision and hearing, insomnia, kidney failure, seizures, and can also lead to paralysis and diseases such as cancer. Acute lead poisoning is accompanied by sudden hallucinations and ends in coma and death.

The lack of macro- and microelements can be compensated by increasing their content in food and drinking water, as well as by taking medications. So, iodine is found in seafood and iodized salt, calcium in eggshells, etc.

Plant cells

Plants belong to eukaryotic organisms, therefore, their cells necessarily contain a nucleus at least at one of the stages of development. Also in the cytoplasm of plant cells there are various organelles, but their distinctive feature is the presence of plastids, in particular chloroplasts, as well as large vacuoles filled with cell sap. The main storage substance of plants - starch - is deposited in the form of grains in the cytoplasm, especially in storage organs. Another essential feature of plant cells is the presence of cellulose cell walls. It should be noted that in plants it is customary to call formations cells, the living contents of which have died out, but the cell walls have remained. Often, these cell walls are impregnated with lignin during lignification, or suberin during corking.

Plant tissue

Unlike animals, in plants, cells are glued together by a carbohydrate median plate; between them there can also be intercellular spaces filled with air. During life, tissues can change their functions, for example, xylem cells first perform a conducting function, and then a supporting function. Plants have up to 20–30 types of tissues, uniting about 80 types of cells. Plant tissues are divided into educational and permanent.

Educational, or meristematic, tissues take part in the processes of plant growth. They are located at the tops of shoots and roots, at the bases of internodes, form a layer of cambium between the bast and wood in the stem, and also underlie cork in lignified shoots. The constant division of these cells supports the process of unlimited plant growth: the educational tissues of the tips of the shoot and root, and in some plants also internodes, ensure the growth of plants in length, and cambium in thickness. When a plant is damaged, wound educational tissues are formed from the cells that are on the surface, which fill the gaps that have arisen.

Permanent fabrics plants specialize in performing certain functions, which is reflected in their structure. They are incapable of division, however, under certain conditions, they can regain this ability (with the exception of dead tissue). Permanent tissues include integumentary, mechanical, conductive and basic tissues.

Covering tissue plants protect them from evaporation, mechanical and thermal damage, penetration of microorganisms, and ensure the exchange of substances with the environment. The integumentary tissues include the skin and cork.

Skin, or epidermis, is a single-layer tissue devoid of chloroplasts. The skin covers the leaves, young shoots, flowers and fruits. It is permeated with stomata and can carry various hairs and glands. From above the peel is covered cuticle from fat-like substances, which protects plants from excessive evaporation. For this, some hairs on its surface are also intended, while glands and glandular hairs can secrete various secrets, including water, salts, nectar, etc.

Stomata- these are special formations through which the evaporation of water occurs - transpiration... In the stomata, guard cells surround the stomatal gap, and there is free space under them. Stomatal guard cells are most often bean-shaped; they contain chloroplasts and starch grains. The inner walls of the guard cells of the stomata are thickened. If the guard cells are saturated with water, then the inner walls stretch and the stomata open. The saturation of guard cells with water is associated with the active transport of potassium ions and other osmotically active substances in them, as well as the accumulation of soluble carbohydrates during photosynthesis. Through the stomata, not only water evaporation occurs, but also gas exchange in general - the supply and removal of oxygen and carbon dioxide, which penetrate further through the intercellular spaces and are consumed by cells in the process of photosynthesis, respiration, etc.

Cells traffic jams, which mainly covers lignified shoots, are impregnated with a fat-like substance suberin, which, on the one hand, causes cell death, and on the other hand, prevents evaporation from the plant surface, thereby providing thermal and mechanical protection. In the cork, as in the skin, there are special formations for airing - lentils... Cork cells are formed as a result of the division of the cork cambium that underlies it.

Mechanical fabrics plants perform supporting and protective functions. These include collenchyma and sclerenchyma. Collenchyma is a living mechanical tissue with elongated cells with thickened cellulose walls. It is characteristic of young, growing plant organs - stems, leaves, fruits, etc. Sclerenchyma- this is a dead mechanical tissue, the living contents of the cells of which die off due to the lignification of the cell walls. In fact, only thickened and lignified cell walls remain from the cells of the sclerenchyma, which is the best possible way to help them perform their respective functions. Mechanical tissue cells are most often elongated and are called fibers. They accompany the cells of the conductive tissue in the composition of bast and wood. Singles or grouped stony cells sclerenchyma of a round or stellate shape are found in unripe fruits of pear, hawthorn and mountain ash, in water lily and tea leaves.

By conductive tissue the transport of substances through the body of the plant is carried out. There are two types of conductive tissue: xylem and phloem. Part xylem, or wood, includes conductive elements, mechanical fibers and cells of the underlying tissue. The living content of the cells of the conductive elements of the xylem - vessels and tracheid- dies early, only lignified cell walls remain of them, as in the sclerenchyme. The function of xylem is the ascending transport of water and mineral salts dissolved in it from the root to the shoot. Phloem, or bast, is also a complex tissue, since it is formed by conductive elements, mechanical fibers and cells of the underlying tissue. Cells of conductive elements - sieve tubes- alive, but the nuclei disappear in them, and the cytoplasm mixes with the cell sap to facilitate the transport of substances. The cells are arranged one above the other, the cell walls between them have numerous holes, which makes them look like a sieve, which is why the cells are called sieve... The phloem transports water and organic substances dissolved in it from the aboveground part of the plant to the root and other organs of the plant. Loading and unloading of sieve tubes is ensured by the adjacent companion cells. Main fabric not only fills the gaps between other tissues, but also performs nutritional, excretory and other functions. The nutritional function is performed by photosynthetic and storage cells. For the most part this parenchymal cells, that is, they have almost the same linear dimensions: length, width and height. The main tissues are located in leaves, young stems, fruits, seeds and other storage organs. Certain types of underlying tissue are capable of performing a suction function, such as the cells of the hairy layer of the root. The selection is carried out by a variety of hairs, glands, nectaries, resin passages and containers. A special place among the main tissues belongs to the milkmen, in whose cell sap rubber, gutta, and other substances accumulate. In aquatic plants, the growth of the intercellular spaces of the main tissue is possible, as a result of which large cavities are formed, with the help of which ventilation is carried out.

Plant organs

Vegetative and generative organs

Unlike animals, the body of plants is dissected into a small number of organs. They are divided into vegetative and generative. Vegetative organs support the vital functions of the body, but do not participate in the process of sexual reproduction, while generative organs perform exactly this function. The vegetative organs include the root and shoot, and the generative (in flowering) organs - the flower, seed and fruit.

Root

Root- This is an underground vegetative organ that performs the functions of soil nutrition, plant anchoring in the soil, transport and storage of substances, as well as vegetative reproduction.

Root morphology. The root has four zones: growth, absorption, holding and root cap. Root cap protects the cells of the growth zone from damage and facilitates the advancement of the root among the solid particles of the soil. It is represented by large cells that are capable of licking and dying over time, which facilitates the growth of the root.

Growth zone consists of cells capable of division. Some of them, after division, increase in size as a result of stretching and begin to perform their inherent functions. Sometimes the growth zone is subdivided into two zones: division and stretching.

V suction zone the cells of root hairs are located, which perform the function of absorbing water and minerals. Root hair cells do not live long, exfoliating 7-10 days after formation.

V zone of, or lateral roots, substances are transported from the root to the shoot, and root branching also occurs, that is, the formation of lateral roots, which contributes to the anchoring of the plant. In addition, in this zone, it is possible to store substances and lay kidneys, with the help of which vegetative reproduction can occur.