What do you need to know for the OGE in biology in order to pass it? Essay “my favorite subject is biology”

Biology is familiar to all of us from school. Its study is long and painful - somewhere from the fifth or sixth grade and ad infinitum (if a student at the university needs to study this subject). But the task of quickly learning biology comes when a student is preparing for an exam.

We have prepared for you some useful tips on how to quickly learn a table, paragraph, retelling or any topic in biology.

6 ways to learn biology quickly

1. Review biology questions for the exam/test. Cross out the ones you know well. Use a marker of the same color to mark those that you know partially. Use a marker of a different color to mark those questions that are completely unknown to you.

Do you know that…

Is the bite of a hamster much worse than the bite of a stronger and larger animal? And all because of its thin and long teeth, which diverge in different directions during a bite. As a result, the wound is not only deep, but also torn and quite painful.

1. When studying an unfamiliar or incomprehensible topic, the main thing is to remember the essence. Then restate the question in your own words, and only then try to understand the finer details. Writing down (at least a brief abstract) the main points will allow you to quickly master the material.
2. Write complex terms and definitions on a separate sheet. Learn not only the meaning of the terms themselves, but also how to use them to solve biological problems. Try to retell each term in your own words.
3. You can remember the terms quite quickly. First, remember that they all come from the Latin language, which has basic suffixes and prefixes. These suffixes and prefixes are repeated quite often. Therefore, knowing their meaning, you will quickly understand the meaning of even a new long and incomprehensible word.

Do you know that…

Do ants also have different professions? For example, among them there are even surgeons who treat patients in a room specially designated for this purpose. First, the surgeon examines the victim, then dresses the wound and treats it with a special clear liquid from his own mouth. Agree, it’s quite convenient, because you don’t need to run to the pharmacy to get your medicine!

By the way! For our readers there is now a 10% discount on

1. When studying questions for the exam, be sure to write cheat sheets. Moreover, you must write it yourself and by hand - this uses mechanical and visual memory.
2. Frequent breaks help you absorb information much faster than taking study breaks every hour or two. Ideally, short breaks should be taken every 20 minutes. And try to go out into the fresh air for at least 5 minutes every hour. During this time, the brain has time to saturate itself with oxygen and rest in order to continue productive assimilation of information.

Here's a video for those who want to get a general idea of ​​biology:

Agree - quite simple tips that will help you quickly prepare for a biology exam or even learn this subject from scratch. Well, if this doesn’t help, don’t worry. There are always people next to you, ready to lend a helping hand and provide support at any time.

Level B. Other.

Why do I like biology?

Why do I like biology? It is a simple question to answer. Everyone has his own hobby. My hobby is biology-science about nature. But why is it so interesting for me? Let us find it out.

Firstly, biology has different sections, for example: anatomy, zoology, botany ad others. And it is a main reason that is why I like it! Because you may choose anything you like most of all and begin to learn more and more. Of course, everyone must know biology at least on basic level. It helps you while planting plants, watering flowers in a right proportion and taking care of our favorite pets. As for me, I want to study it professionally.

Secondly, studying biology is a very interesting process. During all the time you learn a lot of interesting facts about nature and animals, which surround us and it seems that nothing can be more exciting. But it is not right at all. I clearly understand that and I can name other interesting sciences for me: chemistry, ginetics, cytology and others.

Thirdly, biology like as chemistry is very important for my future profession, because I want to become a well-studied doctor and work in the prestige ambulance. May be it is hard to believe, but I do my best in order to reach my dream.

In conclusion, I want to say that everyone has their own abilities to any science they like. My choice is biology, which has a huge amount of its own secrets and riddles.

Why do I like biology? It's easy to answer this question. Everyone has their own hobby. My hobby is biology - the science of nature. But why is she so interesting to me? Let's look into this.

Firstly, there are many different sections in biology, for example: anatomy, zoology, botany and others. And this is the main reason why I like it so much! Because you can choose whatever you like the most and start studying more and more. Of course, everyone should know biology at least at a basic level. It helps you water your flowers in the right proportion and take care of your beloved pets. What about me, I want to study it professionally.

Secondly, studying biology is a very interesting process. All the time you study many interesting facts about nature and animals that surround us and it seems that nothing could be more fascinating. But in general this is not the case. I understand this perfectly and can name other interesting sciences for me: chemistry, genetics, cytology and others.

Thirdly, biology, like chemistry, is very important for my future profession, because I want to become a well-trained doctor and work in a prestigious hospital. It may be hard to believe, but I am doing everything I can to achieve my dream.

In conclusion, I want to say that everyone has their own aptitude for any science they like. My choice is biology, which has a huge number of secrets and mysteries.

You can read everything you need to know about the OGE in biology in 2019 - how to prepare, what to pay attention to, why points can be deducted, what the participants of the OGE from last year advise.

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Biology(from Greek bios- life, logo- 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 the whole 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 only in 1802 it was first used independently by J. B. Lamarck and G. R. Treviranus to denote the science that studies living organisms.

Biological Sciences

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

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

In turn, each of the listed biological sciences is divided into biochemistry, morphology, anatomy, physiology, embryology, genetics and systematics (plants, animals or microorganisms). Biochemistry is the science of the chemical composition of living matter, the chemical processes occurring in living organisms and underlying their life activity. Morphology- biological science that studies the form and structure of organisms, as well as the patterns 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 is considered as part of zoology, and human anatomy is a separate science. Physiology- biological science that studies the life processes of plant and animal organisms, their individual systems, organs, tissues and cells. There is physiology of plants, animals and humans. Embryology (developmental biology)- a branch of biology, the science of the individual development of an organism, including the development of the embryo.

Object genetics are the laws of heredity and variability. Currently, it is one of the most dynamically developing biological sciences.

According to the level of organization of living nature being studied, molecular biology, cytology, histology, organology, biology of organisms and superorganismal 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 branch of morphology, the object of which is the structure of tissues of plants and animals. The field of organology includes the morphology, anatomy and physiology of various organs and their systems.

Organismal biology includes all sciences that deal with living organisms, e.g. ethology- the science of the behavior of organisms.

The biology of supraorganismal systems is divided into biogeography and ecology. Studies the distribution of living organisms biogeography, whereas ecology- organization and functioning of supraorganismal systems at various levels: populations, biocenoses (communities), biogeocenoses (ecosystems) and the biosphere.

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

Identifying 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 science and anthropology. Evolutionary doctrine studies the causes, driving forces, mechanisms and general patterns of evolution of living organisms. One of its sections is paleontology- a science whose subject is the fossil remains of living organisms. Anthropology- a section of general biology, the science of the origin and development of humans as a biological species, as well as the diversity of modern human populations and the patterns of their interaction.

Applied aspects of biology are included in the field of biotechnology, breeding and other rapidly developing sciences. Biotechnology is the biological science that studies the use of living organisms and biological processes in production. It is widely used in the food (baking, cheese-making, brewing, etc.) and pharmaceutical industries (production of antibiotics, vitamins), for water purification, etc. Selection- the science of methods for creating breeds of domestic animals, varieties of cultivated plants and strains of microorganisms with properties necessary for humans. Selection is also understood as the process of changing living organisms, carried out by humans for their needs.

The progress of biology is closely related to the successes of other natural and exact sciences, such as physics, chemistry, mathematics, computer science, etc. For example, microscopy, ultrasound (ultrasound), tomography and other methods of biology are based on physical laws, and the study of the structure of biological molecules and processes occurring in living systems would be impossible without the use of chemical and physical methods. The use of mathematical methods makes it possible, on the one hand, to identify the presence of a natural connection between objects or phenomena, to confirm the reliability of the results obtained, and on the other hand, to model a phenomenon or process. Recently, computer methods, such as modeling, have become increasingly important in biology. At the intersection of biology and other sciences, a number of new sciences arose, such as biophysics, biochemistry, bionics, etc.

Achievements of 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); deciphering the genetic code (R. Holley, H. G. Korana, M. Nirenberg); discovery of gene structure and genetic regulation of protein synthesis (A. M. Lvov, F. Jacob, J. L. Monod, etc.); formulation of cell theory (M. Schleiden, T. Schwann, R. Virchow, K. Baer); study of patterns of heredity and variability (G. Mendel, H. de Vries, T. Morgan, etc.); formulation of the principles of modern systematics (C. Linnaeus), evolutionary theory (C. Darwin) and the doctrine of the biosphere (V. I. Vernadsky).

“ mad cow disease" (prions).

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 humans have about 25–30 thousand genes, but information from most of our DNA is never read , since it contains a huge number of regions and genes encoding traits that have lost significance for humans (tail, body hair, etc.). In addition, a number of genes responsible for the development of hereditary diseases, as well as drug target genes, have been deciphered. 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 will become clear what their differences are. 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, the 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 livestock with feed through the introduction of new plant varieties and advanced technologies for their cultivation. Due to the fact that the genetically programmed properties of agricultural crops have already been almost exhausted, a further solution to 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 many diseases, mechanisms of immunity, 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 is produced on the basis of natural raw materials, as well as thanks to the successes of genetic engineering, such as, for example, insulin, so necessary for patients with diabetes, is mainly synthesized by bacteria to which the corresponding gene has been transferred.

Biological research is no less important for preserving the environment and the diversity of living organisms, the threat of extinction of which calls into question the existence of humanity.

The greatest significance among the achievements of biology is the fact that they even form the basis for the construction of neural networks and genetic code in computer technology, and are also widely used in architecture and other industries. Without a doubt, the 21st century is the century of biology.

Methods of knowledge 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, methods such 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 using the senses or instruments, determined by the task of the activity. The main condition for scientific observation is its objectivity, that is, the ability to verify the data obtained through repeated observation or the use of other research methods, such as 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 is more accurate than qualitative data.

Based on observational data, it is formulated hypothesis- a presumptive judgment about the natural connection of phenomena. The hypothesis is tested in a series of experiments. An experiment is called a scientifically conducted experiment, observation of the phenomenon being studied under controlled conditions, allowing one 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 constructing and studying their models. Essentially, 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.

The experimental and simulation results are subject to careful analysis. Analysis called a method of scientific research by decomposing an object into its component parts or mentally dismembering an object through 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 withstand 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 idea of ​​the patterns and essential connections of reality. The general direction of scientific research is to achieve higher levels of predictability. If no facts can change a theory, and the deviations from it that occur are regular and predictable, then it can be elevated to the rank of law- necessary, essential, stable, repeating relationship between phenomena in nature.

As the body of knowledge increases and research methods improve, hypotheses and well-established theories can be challenged, modified, and even rejected, since scientific knowledge itself is dynamic in nature and constantly subject to critical reinterpretation.

Historical method reveals patterns of the appearance and development of organisms, the formation of their structure and function. In a number of cases, with the help of this method, hypotheses and theories that were previously considered false gain new life. This, for example, happened with Charles Darwin’s assumptions about the nature of signal transmission in 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 patterns of emergence and development of various forms of life.

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

Carrying out observations and experiments often requires 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. Based on the number of cells that make up organisms, they are divided into unicellular and multicellular. The cellular level of organization in unicellular organisms (amoeba vulgaris, 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 single-celled forms, but they ensured the functioning of both biogeocenoses and the biosphere as a whole. Most multicellular organisms are represented by a collection of tissues and organs, which in turn also have a cellular structure. Organs and tissues are adapted to perform specific functions. The elementary unit of this level is the individual in its individual development, or ontogenesis, therefore the organismal level is also called ontogenetic. An elementary phenomenon at this level is changes in the body in its individual development.

Population-species level

Population- this is a collection of individuals of the same species, freely interbreeding with each other and living separately from other similar groups of individuals.

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

Biogeocenotic level

Biogeocenosis represents 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 occurs, determined by the vital activity of organisms. Biogeocenoses themselves are elementary units of a given level, while elementary phenomena are flows of energy and cycles of substances in them. Biogeocenoses make up the biosphere and determine all the processes occurring 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 part of the atmosphere, the hydrosphere and the upper layer of the lithosphere. The biosphere, like all other biological systems, is dynamic and is actively transformed by living beings. It itself is an elementary unit of the biosphere level, and the processes of 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 makes its contribution to a single evolutionary process: in the cell, not only the embedded hereditary information is reproduced, but also its change occurs, which leads to the emergence of new combinations of characteristics and properties of the organism, which in turn are subject to 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 compared to their mechanical totality. Thus, organisms consist of organs, organs are formed by tissues, and tissues form cells.

The characteristic features of biological systems are their integrity, the level principle of organization, as discussed above, and openness. The integrity of biological systems is largely achieved through self-regulation, operating on the feedback principle.

TO open systems include systems between which the exchange of substances, energy and information occurs between them and the environment, 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 studies the structure of a cell, its life 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. Virchow).

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.

Basic principles of 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 naturally interconnected with each other, representing 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, and organs are made up of tissues. The life of an organism as a whole is determined by the interaction of its constituent cells. Cells of multicellular organisms have a full set of genes, but differ from each other in that different groups of genes work in them, which results in morphological and functional diversity of cells - differentiation.

Thanks to the creation of the cellular 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 living things. 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 inherent patterns inevitably suggested the universality of the structure of living organisms. The identification of the unity of the chemical composition and 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 during embryonic development has become a dogma of modern embryology.

About 80 chemical elements are found in living organisms, but only 27 of these elements have their functions in the cell and organism established. The remaining 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 macroelements and microelements.

The concentration of each macronutrients in the body exceeds 0.01%, and their total content is 99%. Macroelements 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.

Without the remaining macroelements, normal functioning of the body is impossible. Thus, potassium, sodium and chlorine are involved in the processes of cell excitation. Potassium is also necessary for the functioning of many enzymes and the retention of water in the cell. Calcium is found in the cell walls of plants, bones, teeth, and mollusk shells and is required for muscle cell contraction and intracellular movement. Magnesium is a component of chlorophyll, a pigment that ensures photosynthesis occurs. It also takes part in protein biosynthesis. Iron, in addition to being 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.

Microelements are contained in the body in concentrations of less than 0.01%, and their total concentration in the cell does not reach 0.1%. Microelements include zinc, copper, manganese, cobalt, iodine, fluorine, etc. Zinc is part of the molecule of the pancreatic hormone - insulin, copper is required for the processes of 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 normal metabolism, and fluoride is associated with the formation of tooth enamel.

Both deficiency and excess or disturbance 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, a deficiency of iron - anemia, and a lack of iodine - a violation of the formation of thyroid hormones and a decrease in metabolic rate. A decrease in fluoride intake from water and food largely determines the disruption of tooth enamel renewal and, as a consequence, 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. Thus, iodine is found in seafood and iodized salt, calcium is found in eggshells, etc.

Plant cells

Plants are eukaryotic organisms, therefore, their cells necessarily contain a nucleus at at least one of the stages of development. Also in the cytoplasm of plant cells there are various organelles, but their distinctive property 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, cells are usually called formations whose living contents have died off, but the cell walls remain. Often these cell walls are impregnated with lignin during lignification, or with suberin during suberization.

Plant tissues

Unlike animals, the cells of plants are glued together by a carbohydrate middle plate; between them there may 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 one. 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 plant growth processes. They are located at the tops of shoots and roots, at the bases of internodes, form a layer of cambium between the phloem and wood in the stem, and also underlie the plug in woody shoots. The constant division of these cells supports the process of unlimited plant growth: the educational tissues of the shoot and root tips, and in some plants, the internodes, ensure the growth of plants in length, and the cambium in thickness. When a plant is damaged, wound tissues are formed from cells on the surface that fill the resulting gaps.

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

Integumentary tissues 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 penetrated by stomata and can bear various hairs and glands. The top skin is covered cuticle of fat-like substances that protects plants from excess evaporation. Some hairs on its surface are also intended for this purpose, while glands and glandular hairs can secrete various secretions, including water, salts, nectar, etc.

Stomata- these are special formations through which water evaporates - transpiration. In stomata, guard cells surround the stomatal fissure, and there is free space underneath them. The guard cells of stomata are most often bean-shaped and 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 opens. 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 entry 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 saturated with a fat-like substance suberin, which, on the one hand, causes cell death, and on the other, prevents evaporation from the surface of the plant, thereby providing thermal and mechanical protection. In the cork, as in the skin, there are special formations for ventilation - lentils. Cork cells are formed by division of the cork cambium underlying it.

Mechanical fabrics plants perform supporting and protective functions. These include collenchyma and sclerenchyma. Collenchyma is a living mechanical tissue that has elongated cells with thickened cellulose walls. It is characteristic of young, growing plant organs - stems, leaves, fruits, etc. Sclerenchyma- this is dead mechanical tissue, the living contents of the cells of which die off due to lignification of the cell walls. In fact, all that remains of the sclerenchyma cells are thickened and lignified cell walls, which is the best way for them to perform their respective functions. Mechanical tissue cells are most often elongated and are called fibers. They accompany conductive tissue cells in bast and wood. Single or in groups stony cells round or star-shaped sclerenchymas are found in unripe fruits of pear, hawthorn and rowan, in the leaves of water lilies and tea.

By conductive tissue transport of substances throughout the plant body occurs. There are two types of conducting tissue: xylem and phloem. Part xylem, or wood, includes conductive elements, mechanical fibers and cells of the main tissue. The living contents of the cells of the conducting elements of the xylem - vessels And tracheid- dies early, leaving only lignified cell walls, as in sclerenchyma. The function of xylem is the upward 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 main tissue. Cells of conducting elements - sieve tubes- alive, but the nuclei disappear in them, and the cytoplasm mixes with cell sap to facilitate the transport of substances. The cells are located 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-like. Phloem transports water and organic substances dissolved in it from the aboveground part of the plant to the root and other plant organs. Loading and unloading of sieve tubes is ensured by 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. Mostly this parenchyma cells, i.e. 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. Some types of underlying tissue are capable of performing an absorptive function, such as the cells of the hairy layer of the root. The secretion is carried out by various hairs, glands, nectaries, resin ducts and containers. A special place among the main tissues belongs to lacticifers, in whose cell sap rubber, gutta and other substances accumulate. In aquatic plants, the intercellular spaces of the main tissue may grow, resulting in the formation of large cavities through which ventilation is carried out.

Plant organs

Vegetative and generative organs

Unlike animals, the body of plants is divided 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, whereas generative organs perform exactly this function. Vegetative organs include the root and shoot, and generative organs (in flowering plants) include the flower, seed and fruit.

Root

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

Root morphology. The root has four zones: growth, absorption, conduction and root cap. Root cap protects the cells of the growth zone from damage and facilitates the movement of the root among solid soil particles. It is represented by large cells that can mucus and die over time, which facilitates root growth.

Growth zone consists of cells capable of dividing. 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 divided into two zones: divisions And stretching.

IN suction zone There are root hair cells that perform the function of absorbing water and minerals. Root hair cells do not live long, sloughing off 7–10 days after formation.

IN venue area, or lateral roots, substances are transported from the root to the shoot, and root branching also occurs, i.e., 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 buds, with the help of which vegetative reproduction can occur.

There is a special method for learning biology yourself at home from scratch. To complete it, you just need not to worry, be patient, have good textbooks and visual aids. Self-organization and a large amount of time for preparation play a significant role in success.

If you need to take an exam in biology, but don’t have money for a tutor, then you can study this natural science yourself. First, you should assess your level of knowledge. If this is zero, then you need to set aside enough time for independent study of biology in order to thoroughly study all the topics and understand them. To do this, you should familiarize yourself with the Unified State Exam program and draw up a detailed work plan. You need to calculate how many topics the program includes and how long it will take to process each one.

It is necessary to prepare for each topic separately, and not for all at once. The branches of biology are logically interconnected. The acquired knowledge is increased step by step. Therefore, basic terms and concepts are studied first, and then more serious topics. Only when one topic is learned well can you move on to the next. The main condition for independent learning is strict adherence to the schedule. By shirking and leaving everything until the very last day, you may never learn anything. If biology is relatively easy, then you can spend at least one week studying it. If natural science is very difficult to understand, this period must be increased.

You should acquire textbooks for all biology courses, get explanatory manuals, and retrieve biology notebooks from all your years of study from your own archives. You need to read in short paragraphs. After each reading, you need to understand the material well and write a short summary on it from memory. This way you can highlight the main and important points for yourself. When studying a subject, the school textbook should be considered the fundamental source of knowledge. Other sources of information are best used as clear explanations or as useful additions to the textbook, but not as primary material.

When writing a summary, it is recommended to make various drawings, diagrams, graphs and tables by hand that briefly convey the essence of what is being read. Such notes are well remembered and associated with the desired section. The notebook fields should be left blank, leaving space for future notes and clarifications. You need to memorize your manuscript and check your knowledge using the table of terms. If there are unfamiliar names in the table, they must be included in the notes in the section to which they relate.

For each topic, you should complete half of the tasks and check your level of self-preparation. If the assignments fail, then the difficult topic needs to be learned better. If the tasks are given easily and correctly, then you can solve the second part of the tasks, thereby developing skills. After completing all the tasks, you need to work on your mistakes: highlight all the tricky questions and read them again.

Required course program

To know which topics in biology you need to learn for the exam, you need to familiarize yourself with the full course program. School biology education includes the following sections:

1. Biology is the science of living nature. You need to know the definition of the term “biology” and methods of its research. Learn the signs of living things, cell structure and metabolic processes.
2. Cell as a biological system. This includes the following subtopics: cell diversity, cell structure, functions of its organelles, metabolism, nutrition and cell reproduction.
3. Organism as a biological system. To master this section, you need to understand what it is: single- and multicellular organisms, viruses, auto- and heterotrophs, the principle of the formation of tissues from cells, the reproduction of organisms and genetics.
4. Diversity of organisms. It is necessary to master taxonomic categories, learn the 5 kingdoms of living organisms, and remember the structural features and vital functions of chordate organisms.
5. Man and his health. This section includes the structure and functioning of human tissues, organs and systems, knowledge of personal hygiene.
6. Superorganismal systems and the evolution of the organic world. You should familiarize yourself with the theories of evolutionary ideas, the diversity of existing species, and the history of human origins.
7. Ecosystems and their inherent patterns. We must remember what an ecosystem is, what its varieties are, how the cycle of substances occurs in nature. It is also necessary to familiarize yourself with the teachings of Vernadsky and learn what the bio- and noosphere are.

To make it easier to study the material, topics need to be arranged in a logical order. First, the basics of all living things, such as cells, are studied. Then more general items, such as fabrics. Next, the already studied tissues are formed into organs or the process of evolution from protozoa to multicellular is studied. You just need to understand that biology is not a collection of different sections, but interrelated topics that flow from each other.

What is the easiest way to understand a subject on your own?

Without a tutor, of course, it is more difficult to understand biology on your own. But there is nothing scary in this science. It just needs to be perceived easily, as something educational and interesting, then its memorization will be easier - through awareness of each topic.

It is always recommended to prepare for the exam using special textbooks. They contain all the necessary information. But they are also oversaturated with complex terms that make it difficult to perceive and understand what is written. Therefore, in addition to textbooks, it is advisable to use various manuals written in simple layman’s language. They will help you interpret and understand what is presented in the textbook. It is better to read silently, because when speaking words out loud, attention is scattered and the information is remembered worse.

Scientific films can be used as additional auxiliary educational material. They will cover topics that are difficult to understand in detail and clearly. In addition, when watching educational films, visual and auditory memory works, which gives a higher level of memorability.

You can’t leave a topic you’ve read unlearned. If after multiple readings the topic remains unexplored, it needs to be analyzed in more detail. You cannot move on to studying the next material if you have not learned the previous one. You need to study in small portions. After reading the page, you need to briefly tell yourself what was discussed. If everything is clear, you should continue reading. If not, read it again. Constant self-monitoring of knowledge will allow you to identify gaps in memory and evenly learn all the material.

Will tell you about seven professions related to this subject. Of course, you shouldn’t equate the lesson with the specifics of the job, but it’s not a bad idea to take a closer look at professions where you can apply knowledge in the subject.

Biologist

Studies the general properties and features of the development of living nature. Specializes in one or more areas (zoology, botany, anatomy, genetics, microbiology, etc.) or works at the intersection of sciences (biochemistry, biophysics, bioecology). A biologist collects information about the object of study, for example, observes a population. He also conducts experiments, analyzes and summarizes the information received, and applies it in practice to solve certain problems. This specialist is inquisitive, observant, responsible and patient. Choosing to become a biologist means that you will be engaged in research and teaching activities. You can study to become a biologist in.

Ecologist

If you are concerned about environmental problems, if you want to save nature from the destructive actions of humans, this is the profession that you need. However, there are more prosaic everyday life in such work than heroic rescue operations. Ecologists monitor compliance with environmental standards, draw up reports on the use of natural resources and waste disposal. They calculate the damage caused or potential harm to the environment. In addition to knowledge of biology and chemistry, you will need the ability to maintain documentation and convince management of the need to improve production so that it does not worsen the environment. Environmentalists have to interact more with society, eradicate its shortcomings, and only then contact nature. You can get a profession as an ecologist in (by correspondence).

Doctor

Agronomist

Who feeds the country with agricultural products? Knows where, when, how to plant plants and harvest? That's right, agronomist! He combines the qualities of a researcher, a prudent owner and a competent manager. He must be aware of the latest methods of cultivation, fertilizing the land and growing crops, and controlling pests. The agronomist draws up a production plan and monitors its implementation. This specialist controls everything: from preparing the soil for sowing to harvesting and storing the crop. Do you like the rural lifestyle? Then this profession may suit you. Programs