Shtanko T.Yu. №221-987-502
Subject: The chemical composition of the cell. Carbohydrates, lipids, their role in the life of the cell .
Lesson glossary: monosaccharides, oligosaccharides, polysaccharides, lipids, waxes, phospholipids.
Personal results: formation cognitive interests and motives for the study of wildlife. Development of intellectual skills, creative abilities.
Metasubject results: the formation of skills to compare, draw a conclusion, reason, formulate definitions of concepts.
Subject Results: characterize the structural features, functions of carbohydrates and lipids,their role in cell life.
UUD: construction of a logical chain of reasoning, comparison, correlation of concepts.
The purpose of the lesson: to acquaint students with the structure, classification and functions of carbohydrates, with the diversity and functions of lipids.
During the classes: knowledge check
Describe the chemical composition of the cell.
Why can it be argued that the chemical composition of the cell is a confirmation of the unity of living nature and the commonality of living and inanimate nature?
Why is carbon considered to be the chemical basis of life?
Choose the correct sequence of chemical elements in order of increasing their concentration in the cell:
a) iodine-carbon-sulfur; b) iron-copper-potassium;
c) phosphorus-magnesium-zinc; d) fluorine-chlorine-oxygen.
Deficiency of what element can cause changes in the shape of limbs in children?
a) iron; b) potassium; c) magnesium; d) calcium.
Describe the structure of the water molecule and its functions in the cell.
Water is a solvent. Polar water molecules dissolve polar molecules of other substances. Substances soluble in water are calledhydrophilic , insoluble in water– hydrophobic .
High specific heat capacity. To break the hydrogen bonds holding water molecules, it is required to absorb a large number of energy. This property of water ensures the maintenance of heat balance in the body.
Thermal conductivity.
Water practically does not compress, providing turgor pressure.
adhesion and surface tension. Hydrogen bonds provide the viscosity of water and adhesion to the molecules of other substances. Due to the adhesion forces, a film is formed on the surface of the water, which is characterized by surface tension.
It can be in three states.
Density. When cooled, the movement of water molecules slows down. The number of hydrogen bonds becomes maximum. Water has the highest density at 4 degrees. Freezing water expands (requires a place for the formation of hydrogen bonds), its density decreases, so the ice floats on the surface of the water.
Select the functions of the water in the cage:
a) energy d) construction
b) enzymatic e) lubricating
c) transport f) thermoregulatory
Select only physical properties water:
a) the ability to dissociate
b) hydrolysis of salts
c) density
d) thermal conductivity
e) electrical conductivity
f) electron donation
The amount of water in the cells of the embryo - 97.55%; eight-month - 83%; newborn - 74%; adult - 66% (bones - 20%, liver - 70%, brain - 86%). The amount of water is directly proportional to the metabolic rate.
How is the acidity or basicity of a solution determined? (concentration of H ions)
How is this concentration expressed? (This concentration is expressed using the pH value)
Neutral pH = 7
Acidic pH less than 7
Basic pH greater than 7
pH scale length up to 14
The pH value in cells is 7 A change of 1-2 units is detrimental to the cell.
How is pH constancy maintained in cells (maintained due to the buffering properties of their contents).
Buffer A solution containing a mixture of a weak acid and its soluble salt is called. As the acidity (H ion concentration) increases, the free anions from the salt readily combine with the free H ions and remove them from the solution. As acidity decreases, additional H ions are released.
As components of the body's buffer systems, ions determine their properties - the ability to maintain pH at a certain level (close to neutral), despite the fact that acidic and alkaline products are formed as a result of metabolism.
Explain what is homeostasis?
Learning new material.
Divide the substances presented into groups. Explain what principle you used for distribution?
Ribose, hemoglobin, chitin, cellulose, albumin, cholesterol, murein, glucose, fibrin, testosterone, starch, glycogen, sucrose
Carbohydrates
Lipids (fats)
Squirrels
ribose
cholesterol
hemoglobin
chitin
testosterone
albumen
cellulose
fibrin
murein
glucose
starch
glycogen
sucrose
Today we will talk about carbohydrates and lipids.
General formula of carbohydrates C (HO) Glucose C H O
Look at the carbs you've identified and try to divide them into 3 groups. Explain what distribution principle you used?
Monosaccharides
disaccharides
Polysaccharides
ribose
sucrose
chitin
glucose
cellulose
murein
starch
glycogen
What is the difference? Define polymer.
Working with drawings:
(P.3-9) Fig.8 Fig.9 Fig.10
Functions of carbohydrates
The values of carbohydrates in the cell
Functions
Enzymatic cleavage of a carbohydrate molecule releases 17.5 kJ
energy
In excess, carbohydrates are found in the cell in the form of starch, glycogen. Enhanced breakdown of carbohydrates occurs during seed germination, prolonged starvation, intense muscle work
storage
Carbohydrates are part of the cell walls, form the chitinous cover of arthropods, and prevent the penetration of bacteria, being released when plants are damaged.
protective
Cellulose, chitin, murein is part of the cell walls. Chitin forms the shell of arthropods
construction, plastic
Participates in the processes of cellular recognition, perceives signals from environment, part of the glycoproteins
receptor, signal
Lipids are fat-like substances.
Their molecules are non-polar, hydrophobic, soluble in organic solvents.
According to the structure, they are divided into simple and complex.
Simple: neutral lipids (fats), waxes, sterols, steroids.
neutral lipids (fats) consist of: see fig. 11
Complex lipids contain a non-lipid component. The most important: phospholipids, glycolipids (as part of cell membranes)
Functions of lipids
Correlate:
Function description Name
1) are part of cell membranes A) energy
2) during the oxidation of 1g. fat is released 38.9 kJ B) water source
3) deposited in plant and animal cells B) regulatory
4) subcutaneous fatty tissue protects organs from hypothermia, shock. D) storage
5) some of the lipids are hormones D) building
6) when 1 g of fat is oxidized, more than 1 g of water is released E) protective
Fixing:
questions p.37 No. 1 - 3; p.39 No. 1 - 4.
D/W: §nine; §ten
Why can we feed on animals, fungi and plants, while bacteria and other animals, in turn, can feed on our body, causing diseases and pathologies? What are organic and not organic matter is necessary for a person to feel normal? Without what chemical elements could life on Earth not exist? What happens with heavy metal poisoning? From this lesson you will learn about what chemical elements are part of living organisms, how they are distributed in the body of animals and plants, as an excess or deficiency chemical substances can affect the life of different creatures, find out details about micro and macro elements and their role in wildlife.
Topic: Fundamentals of Cytology
Lesson: Features chemical composition cells
1. Chemical composition of the cell
The cells of living organisms are made up of different chemical elements.
The atoms of these elements form two classes of chemical compounds: inorganic and organic (see Fig. 1).
Rice. 1. Conditional division of chemicals that make up a living organism
Of the currently known 118 chemical elements, living cells necessarily contain 24 elements. These elements form readily soluble compounds with water. They are also contained in objects of inanimate nature, but the ratio of these elements in living and inanimate matter differs (Fig. 2).
Rice. 2. Relative content of chemical elements in earth's crust and the human body
In inanimate nature, the predominant elements are oxygen, silicon, aluminum and sodium.
In living organisms, the predominant elements are hydrogen, oxygen, carbon and nitrogen. In addition, two more important elements for living organisms are distinguished, namely: phosphorus and sulfur.
These 6 elements, namely carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur (C, H, N, O, P, S) , called organogenic, or nutrients, because they are part of organic compounds, and the elements oxygen and hydrogen, in addition, they form water molecules. Compounds of biogenic elements account for 98% of the mass of any cell.
2. Six basic chemical elements for a living organism
The most important distinguishing ability of the elements C, H, N, O is that they form strong covalent bonds, and of all the atoms that form covalent bonds, they are the lightest. In addition, carbon, nitrogen and oxygen form single and double bonds, due to which they can give a wide variety of chemical compounds. Carbon atoms can also form triple bonds with both other carbon atoms and nitrogen atoms - in hydrocyanic acid, the bond between carbon and nitrogen is triple (Fig. 3)
Fig 3. Structural formula of hydrogen cyanide - hydrocyanic acid
This explains the diversity of carbon compounds in nature. In addition, valence bonds form a tetrahedron around the carbon atom (Fig. 4), due to which various types organic molecules have different three-dimensional structures.
Rice. 4. Tetrahedral shape of the methane molecule. In the center is an orange carbon atom, around four blue hydrogen atoms form the vertices of a tetrahedron.
Only carbon can create stable molecules with a variety of configurations and sizes and a wide variety of functional groups (Fig. 5).
Figure 5. An example of the structural formulas of various carbon compounds.
About 2% of the cell mass is accounted for by the following elements: potassium, sodium, calcium, chlorine, magnesium, iron. The remaining chemical elements are contained in the cell in much smaller quantities.
Thus, all chemical elements according to their content in a living organism are divided into three large groups.
3. Micro-, macro- and ultramicroelements in a living organism
Elements, the amount of which is up to 10-2% of body weight, is macronutrients.
Those elements whose share comes from 10-2 to 10-6 - trace elements.
Rice. 6. Chemical elements in a living organism
Russian and Ukrainian scientist V. I. Vernadsky proved that all living organisms are able to assimilate (assimilate) elements from the external environment and accumulate (concentrate) them in certain organs and tissues. For example, a large number of trace elements accumulate in the liver, bone and muscle tissue.
4. Affinity of microelements for certain organs and tissues
Individual elements have an affinity for certain organs and tissues. For example, calcium accumulates in bones and teeth. Zinc is abundant in the pancreas. There is a lot of molybdenum in the kidneys. Barium in the retina. Iodine in the thyroid gland. There is a lot of manganese, bromine and chromium in the pituitary gland (see the table "Accumulation of chemical elements in the internal organs of a person").
For the normal course of life processes, a strict ratio of chemical elements in the body is necessary. Otherwise, severe poisoning occurs due to a lack or excess of biophilic elements.
5. Organisms that selectively accumulate trace elements
Some living organisms can be indicators chemical conditions environment due to the fact that they selectively accumulate certain chemical elements in organs and tissues (Fig. 7, 8).
Rice. 7. Animals that accumulate certain chemical elements in the body. From left to right: rays (calcium and strontium), rhizomes (barium and calcium), ascidians (vanadium)
Rice. 8. Plants that accumulate certain chemical elements in the body. From left to right: seaweed (iodine), ranunculus (lithium), duckweed (radium)
6. Substances that make up organisms
Chemical compounds in living organisms
Chemical elements form inorganic and organic substances (see the diagram "Substances that make up living organisms").
inorganic substances in organisms: water and minerals(salt ions; cations: potassium, sodium, calcium and magnesium; anions: chlorine, sulfate anion, bicarbonate anion).
organic matter: monomers (monosaccharides, amino acids, nucleotides, fatty acid and lipids) and polymers (polysaccharides, proteins, nucleic acids).
Of the inorganic substances in the cell, most of all water(from 40 to 95%), among organic compounds in animal cells predominate squirrels(10-20%), and in plant cells - polysaccharides (the cell wall consists of cellulose, and the main reserve plant nutrient is starch).
Thus, we have examined the main chemical elements that are part of living organisms, and the compounds that they can form (see Scheme 1).
Importance of nutrients
Consider the importance of biogenic elements for living organisms (Fig. 9).
Element carbon(carbon) is part of all organic substances, their basis is the carbon skeleton. Element oxygen(oxygen) is a part of water and organic substances. Element hydrogen(hydrogen) is also a part of all organic substances and water. Nitrogen(nitrogen) is a part of proteins, nucleic acids and their monomers (amino acids and nucleotides). Sulfur(sulphur) is part of the sulfur-containing amino acids, acts as an energy transfer agent. Phosphorus is part of ATP, nucleotides and nucleic acids, mineral salts of phosphorus - a component of tooth enamel, bone and cartilage tissues.
Ecological aspects of the action of inorganic substances
The problem of environmental protection is primarily related to the prevention of environmental pollution by various inorganic substances . The main pollutants are heavy metals that accumulate in the soil, natural waters.
The main air pollutants are oxides of sulfur and nitrogen.
As a result rapid development technology, the amount of metals used in production has grown extraordinary. Metals enter the human body, are absorbed into the blood, and then accumulate in organs and tissues: liver, kidneys, bone and muscle tissues. Metals are excreted from the body through the skin, kidneys and intestines. Metal ions that are among the most toxic (see the list "The most toxic ions", Fig. 10): mercury, uranium, cadmium, thallium and arsenic cause acute chronic poisoning.
The group of moderately toxic metals is also numerous (Fig. 11), these include manganese, chromium, osmium, strontium and antimony. These elements can cause chronic poisoning with rather severe, but rarely fatal clinical manifestations.
Low toxicity metals do not have significant selectivity. Aerosols of low-toxic metals, for example, alkali, alkaline earth, can cause changes in the lungs.
Homework
1. What chemical elements are part of living organisms?
2. What groups, depending on the amount of the element in living matter, are chemical elements divided into?
3. Name the organogenic elements and give them a general description.
4. What chemical elements are classified as macronutrients?
5. What chemical elements are classified as trace elements?
6. What chemical elements are classified as ultramicroelements?
7. Discuss with friends and family how Chemical properties chemical elements are related to their role in living organisms.
1. Alchemist.
2. Wikipedia.
3. Alchemist.
4. Internet portal Liveinternet. ru.
Bibliography
1. Kamensky A. A., Kriksunov E. A., Pasechnik V. V. General biology 10-11 class Bustard, 2005.
2. Biology. Grade 10. General biology. A basic level of/ P. V. Izhevsky, O. A. Kornilova, T. E. Loshchilina and others - 2nd ed., revised. - Ventana-Graf, 2010. - 224 pages.
3. Belyaev D.K. Biology grade 10-11. General biology. A basic level of. - 11th ed., stereotype. - M.: Education, 2012. - 304 p.
4. Biology grade 11. General biology. Profile level / V. B. Zakharov, S. G. Mamontov, N. I. Sonin and others - 5th ed., stereotype. - Bustard, 2010. - 388 p.
5. Agafonova I. B., Zakharova E. T., Sivoglazov V. I. Biology 10-11 class. General biology. A basic level of. - 6th ed., add. - Bustard, 2010. - 384 p.
periodic table
Chemical elements of the cell
In living organisms, there is not a single chemical element that would not be found in the bodies of inanimate nature (which indicates the commonality of animate and inanimate nature).
Different cells include practically the same chemical elements (which proves the unity of living nature); and at the same time, even the cells of one multicellular organism, performing various functions, may differ significantly from each other in chemical composition.
Of the currently known more than 115 elements, about 80 are found in the composition of the cell.
All elements according to their content in living organisms are divided into three groups:
- macronutrients- the content of which exceeds 0.001% of body weight.
98% of the mass of any cell falls on four elements (they are sometimes called organogens): - oxygen (O) - 75%, carbon (C) - 15%, hydrogen (H) - 8%, nitrogen (N) - 3%. These elements form the basis of organic compounds (and oxygen and hydrogen, in addition, are part of the water, which is also contained in the cell). About 2% of the cell mass accounts for another eight macronutrients: magnesium (Mg), sodium (Na), calcium (Ca), iron (Fe), potassium (K), phosphorus (P), chlorine (Cl), sulfur (S); - The remaining chemical elements are contained in the cell in very small quantities: trace elements- those that account for from 0.000001% to 0.001% - boron (B), nickel (Ni), cobalt (Co), copper (Cu), molybdenum (Mb), zinc (Zn), etc.;
- ultramicroelements- the content of which does not exceed 0.000001% - uranium (U), radium (Ra), gold (Au), mercury (Hg), lead (Pb), cesium (Cs), selenium (Se), etc.
Living organisms are able to accumulate certain chemical elements. So, for example, some algae accumulate iodine, buttercups - lithium, duckweed - radium, etc.
Cell chemicals
Elements in the form of atoms are part of the molecules inorganic and organic cell compounds.
To inorganic compounds
include water and mineral salts.
organic compounds are characteristic only for living organisms, while inorganic exist in inanimate nature.
To organic compounds include carbon compounds with a molecular weight of 100 to several hundred thousand.
Carbon - chemical base life. It can enter into contact with many atoms and their groups, forming chains, rings that make up the skeleton of organic molecules that differ in chemical composition, structure, length and shape. They form complex chemical compounds that differ in structure and function. These organic compounds that make up the cells of living organisms are called biological polymers, or biopolymers. They make up more than 97% of the cell's dry matter.
Biology. General biology. Grade 10. Basic level Sivoglazov Vladislav Ivanovich
5. Chemical composition of the cell
5. Chemical composition of the cell
Remember!
What chemical element?
What chemical elements predominate in the earth's crust?
What do you know about the role of such chemical elements as iodine, calcium, iron in the life of organisms?
One of the main common features of living organisms is the unity of their elemental chemical composition. Regardless of which kingdom, phylum, or class a particular creature, the composition of his body includes the same so-called universal chemical elements. The similarity in the chemical composition of different cells indicates the unity of their origin.
Rice. 8. The shells of unicellular diatoms contain a large amount of silicon
In wildlife, about 90 chemical elements have been discovered, that is, most of all known today. There are no special elements that are characteristic only for living organisms, and this is one of the proofs of the commonality of living and inanimate nature. But the quantitative content of certain elements in living organisms and in the inanimate environment surrounding them differs significantly. For example, silicon in the soil is about 33%, and in land plants only 0.15%. Such differences indicate the ability of living organisms to accumulate only those elements that they need for life (Fig. 8).
Depending on the content, all chemical elements that make up wildlife are divided into several groups.
Macronutrients. I group. The main components of all organic compounds that perform biological functions are oxygen, carbon, hydrogen and nitrogen. All carbohydrates and lipids contain hydrogen, carbon and oxygen, and the composition of proteins and nucleic acids, in addition to these components, includes nitrogen. These four elements account for 98% of the mass of living cells.
II group. The group of macronutrients also includes phosphorus, sulfur, potassium, magnesium, sodium, calcium, iron, chlorine. These chemical elements are essential components of all living organisms. The content of each of them in the cell is from tenths to hundredths of a percent of the total mass.
sodium, potassium and chlorine provide the occurrence and conduction of electrical impulses in the nervous tissue. Maintaining a normal heart rate depends on the concentration in the body sodium, potassium and calcium. Iron participates in the biosynthesis of chlorophyll, is part of hemoglobin (oxygen carrier protein in the blood) and myoglobin (protein containing oxygen in the muscles). Magnesium in plant cells it is part of chlorophyll, and in the animal body it is involved in the formation of enzymes necessary for the normal functioning of muscle, nervous and bone tissues. Proteins often contain sulfur, and all nucleic acids contain phosphorus. Phosphorus is also a component of all membrane structures.
Among both groups of macronutrients, oxygen, carbon, hydrogen, nitrogen, phosphorus and sulfur are combined into a group bioelements , or organogens , based on the fact that they form the basis of most organic molecules (Table 1).
Microelements. There is a large group of chemical elements that are found in organisms in very low concentrations. These are aluminum, copper, manganese, zinc, molybdenum, cobalt, nickel, iodine, selenium, bromine, fluorine, boron and many others. Each of them accounts for no more than thousandths of a percent, and the total contribution of these elements to the cell mass is about 0.02%. Microelements enter plants and microorganisms from soil and water, while animals get them from food, water and air. The role and functions of the elements of this group in various organisms are very diverse. As a rule, trace elements are part of biologically active compounds (enzymes, vitamins and hormones), and their action is manifested mainly in how they affect metabolism.
Table 1. The content of bioelements in a cell
Cobalt is part of vitamin B 12 and takes part in the synthesis of hemoglobin, its deficiency leads to anemia. Molybdenum as part of enzymes, it participates in nitrogen fixation in bacteria and ensures the operation of the stomatal apparatus in plants. Copper is a component of the enzyme involved in the synthesis of melanin (skin pigment), affects the growth and reproduction of plants, the processes of hematopoiesis in animal organisms. iodine in all vertebrates, it is part of the thyroid hormone - thyroxine. Bor affects the growth processes in plants, its deficiency leads to the death of apical buds, flowers and ovaries. Zinc acts on the growth of animals and plants, and is also part of the pancreatic hormone - insulin. a lack of Selene causes cancer in humans and animals. Each element plays its own specific, very important role in ensuring the vital activity of the body.
As a rule, the biological effect of one or another trace element depends on the presence of other elements in the body, i.e., each living organism is a unique balanced system, the normal operation of which depends, among other things, on the correct ratio of its components at any level of organization. For example, manganese improves absorption by the body copper, a fluorine affects metabolism strontium.
Some organisms have been found to intensively accumulate certain elements. For example, many seaweeds accumulate iodine, horsetails - silicon, buttercups - lithium, and mollusks are characterized by a high content copper.
Trace elements are widely used in modern agriculture in the form of microfertilizers to increase crop yields and as feed additives to increase animal productivity. Microelements are also used in medicine.
Ultramicroelements. There is a group of chemical elements that are contained in organisms in trace, i.e. negligible, concentrations. These include gold, beryllium, silver and other elements. The physiological role of these components in living organisms has not yet been finally established.
The role of external factors in the formation of the chemical composition of wildlife. The content of certain elements in the body is determined not only by the characteristics of the given organism, but also by the composition of the environment in which it lives and the food it uses. The geological history of our planet, the peculiarities of soil-forming processes have led to the formation of areas on the Earth's surface that differ from each other in the content of chemical elements. A sharp deficiency or, conversely, an excess of any chemical element causes the occurrence of biogeochemical endemias within such zones - diseases of plants, animals and humans.
In many regions of our country - in the Urals and Altai, in Primorye and in Rostov region the amount of iodine in the soil and water is significantly reduced.
If a person does not receive the right amount of iodine with food, his thyroxine synthesis decreases. The thyroid gland, trying to compensate for the lack of hormone, grows, which leads to the formation of the so-called endemic goiter. Particularly severe consequences from a lack of iodine occur in children. A reduced amount of thyroxine leads to a sharp lag in mental and physical development.
To prevent thyroid disease, doctors recommend salting food with special salt enriched with potassium iodide, eating fish dishes and seaweed.
Almost 2 thousand years ago, the ruler of one of the northeastern provinces of China issued a decree in which he ordered all his subjects to eat 2 kg of seaweed per year. Since then, the inhabitants have obediently observed the ancient decree, and despite the fact that there is a clear lack of iodine in the area, the population does not suffer from thyroid diseases.
Review questions and assignments
1. What is the similarity biological systems and inanimate objects?
2. List the bioelements and explain what their significance is in the formation of living matter.
3. What are trace elements? Give examples and describe the biological significance of these elements.
4. How will the lack of any trace element affect the life of the cell and organism? Give examples of such phenomena.
5. Tell us about ultramicroelements. What is their content in the body? What is known about their role in living organisms?
6. Give examples of biochemical endemics known to you. Explain the reasons for their origin.
7. Draw a diagram illustrating the elemental chemical composition of living organisms.
Think! Execute!
1. By what principle are all chemical elements that make up wildlife divided into macroelements, microelements and ultramicroelements? Suggest your own alternative classification of chemical elements based on a different principle.
2. Sometimes in textbooks and manuals, instead of the phrase "elemental chemical composition" you can find the expression "elemental chemical composition". Explain why this wording is incorrect.
3. Find out if there are any peculiarities in the chemical composition of the water in the area where you live (for example, an excess of iron or a lack of fluorine, etc.). Using additional literature and Internet resources, determine what effect this may have on the human body.
Work with computer
Refer to the electronic application. Study the material and complete the assignments.
Repeat and remember!
Plants
Fertilizers. Nitrogen necessary for plants for the normal formation of vegetative organs. With additional application of nitrogen and nitrogenous fertilizers to the soil, the growth of ground shoots is enhanced. Phosphorus affects the development and maturation of fruits. Potassium promotes the outflow of organic matter from the leaves to the roots, affects the preparation of the plant for winter.
All elements in the composition of mineral salts are obtained from the soil. In order to have high yields, it is necessary to maintain soil fertility and apply fertilizers. In modern agriculture, organic and mineral fertilizers are used, thanks to which cultivated plants receive the necessary nutrients.
organic fertilizers(manure, peat, humus, bird droppings, etc.) contain all the nutrients necessary for the plant. When organic fertilizers are applied, microorganisms enter the soil, which mineralize organic residues and thereby increase soil fertility. Manure must be applied long before sowing seeds, during autumn tillage.
Mineral fertilizers usually contain those elements that are lacking in the soil: nitrogen (sodium and potassium nitrate, ammonium chloride, urea, etc.), potassium (potassium chloride, potassium sulfate), phosphorus (superphosphates, phosphate rock, etc.). Fertilizers containing nitrogen are usually applied in spring or early summer, as they are quickly washed out of the soil. Potash and phosphate fertilizers last longer, so they are applied in the fall. Too much fertilizer is just as bad for plants as too little.
From the book Wolf Behavior (collection of articles) author Krushinsky Leonid ViktorovichComposition of populations and self-regulation As a result of long (more than 20 years) observations of wolf populations in sowing. Minnesota, on about. Isle Royal, in the N.W. territories and in national parks Canada, as well as the study of wolves in natural conditions in Italy and in large enclosures
From the book Doping in Dog Breeding the author Gurman E G11.3. FOOD COMPOSITION The composition of the food should be appropriate to the needs of the body and its ability to absorb the given nutrients from the given composition. Most dietary guidelines (whether human or animal) emphasize the need to balance intake and
From book new science about life author Sheldrake Rupert4.2. Chemical morphogenesis Aggregative morphogenesis occurs with increasing intensity in inorganic systems as the temperature decreases: when the plasma cools, subatomic particles aggregate into atoms; at lower temperatures, the atoms aggregate into
From book latest book facts. Volume 1 [Astronomy and astrophysics. Geography and other earth sciences. Biology and Medicine] author From the book Ant, family, colony author Zakharov Anatoly AlexandrovichCOMPOSITION OF THE FAMILY The use of the term "family" in relation to the population of the anthill is due to the origin of the ant community. These communities arose as a result of the successive strengthening of the bonds of parents with their immediate offspring, and not from random
From the book Tests in Biology. 6th grade the author Benuzh ElenaCELL STRUCTURE OF ORGANISMS CELL STRUCTURE. DEVICES FOR STUDYING THE STRUCTURE OF THE CELL 1. Choose the one most correct answer. A cell is: A. The smallest particle of all living things. The smallest particle of a living plant B. Part of the plant G. Artificially created unit for
From the book Biology [ Complete reference to prepare for the exam] author Lerner Georgy Isaakovich From the book Escape from Loneliness author Panov Evgeny NikolaevichCollectivist Cells and Single Cells There are at least two major reasons for the close cooperation of cells that make up a multicellular organism. Firstly, each individual cell, being in itself extremely skillful and executive
From the book Ants, who are they? author Marikovsky Pavel Iustinovich From the book The Newest Book of Facts. Volume 1. Astronomy and astrophysics. Geography and other earth sciences. Biology and medicine author Kondrashov Anatoly PavlovichWhat is the most common chemical element in the universe? The lightest elements in the universe are hydrogen and helium. The sun, stars, interstellar gas, by the number of atoms, are 99 percent of them. To the share of all others, including the most
From the book How Life Originated and Developed on Earth author Gremyatsky Mikhail AntonovichV. The composition and structure of living bodies Observing the life of plants, animals and humans, we see that a wide variety of changes are constantly taking place with them: they grow, multiply, grow old, die. Various juices, gases, food, etc. are constantly moving inside them.
From the book Problems of therapeutic starvation. Clinical and experimental studies [all four parts!] author Anokhin Petr KuzmichChemical composition of rat tissues during complete starvation VI DOBRYNINA (Moscow) Fasting as a method of treatment has successfully proven itself in some mental and somatic diseases (3, 7, 10-13). Especially promising is its use in metabolic, allergic
From the book Breeding fish, crayfish and poultry author Zadorozhnaya Lyudmila Alexandrovna From the book The Current State of the Biosphere and Environmental Policy author Kolesnik Yu. A.1.2. Characteristics and composition of the biosphere early XIX in. He emphasized that all the substances that are on the surface of the globe and form its crust were formed due to
In the last century, the main fuel was firewood. Even in our time, firewood as fuel still has great importance especially for heating buildings in rural areas. When burning wood in stoves, it is hard to imagine that we are, in fact, using energy received from the Sun, located at a distance of about 150 million kilometers from the Earth. However, that is exactly what is happening.
How did solar energy get accumulated in wood? Why can we say that when we burn wood, we use the energy received from the Sun?
The outstanding Russian scientist K. A. Timiryazev gave a clear answer to the questions posed. It turns out that the development of almost all plants is possible only under the action of sunlight. The life of the vast majority of plants from small grass to powerful eucalyptus, reaching 150 meters in height and 30 meters in circumference of the trunk, is based on the perception of sunlight. Green leaves of plants contain a special substance - chlorophyll. This substance gives plants important property: absorb the energy of sunlight, decompose due to this energy carbon dioxide, which is a compound of carbon and oxygen, into its constituent parts, i.e., into carbon and oxygen, and form organic substances in its tissues, of which plant tissues actually consist. Without exaggeration, this property of plants can be called remarkable, because thanks to it, plants are able to convert inorganic substances into organic substances. In addition, plants absorb carbon dioxide from the air, which is a product of the activities of living beings, industry and volcanic activity, and saturate the air with oxygen, without which, as you know, the processes of respiration and combustion are impossible. That is why, by the way, green spaces are essential for human life.
Verifying that plant leaves take in carbon dioxide and separate it into carbon and oxygen is easy with a very simple experiment. Imagine that in a test tube there is water with carbon dioxide dissolved in it and green leaves of some tree or grass. Water containing carbon dioxide is very widespread: on a hot day, it is this water, called carbonated, that is very pleasant to quench your thirst.
Let us return, however, to our experience. After some time, small bubbles can be seen on the leaves, which, as they form, rise and accumulate in the upper part of the tube. If this gas, obtained on the leaves, is collected in a separate vessel and then a slightly smoldering splinter is introduced into it, then it will flare up with a bright flame. On this basis, as well as on a number of others, it can be established that we are dealing with oxygen. As for carbon, it is absorbed by the leaves and organic substances are formed from it - plant tissues, the chemical energy of which, which is the converted energy of the sun's rays, is released during combustion in the form of heat.
In our story, which of necessity touches on various branches of natural science, another new concept has come across: chemical energy. It is necessary to at least briefly explain what it is. The chemical energy of a substance (in particular firewood) has much in common with thermal energy. Thermal energy, as the reader remembers, is the sum of the kinetic and potential energy of the smallest particles of the body: molecules and atoms. The thermal energy of a body is thus defined as the sum of the energy of the translational and rotational motion of the molecules and atoms of a given body and the energy of attraction or repulsion between them. The chemical energy of a body, unlike thermal energy, is made up of the energy accumulated inside the molecules. This energy can only be released through a chemical transformation, chemical reaction when one or more substances are converted into other substances.
Two important clarifications must be added to this. But first it is necessary to remind the reader of some provisions about the structure of matter. For a long time, scientists assumed that all bodies consist of the smallest and further indivisible particles - atoms. In Greek, the word "atom" means indivisible. In its first part, this assumption was confirmed: all bodies really consist of atoms, and the dimensions of these latter are extremely small. The weight of a hydrogen atom, for example, is 0.0000000000000000000000017 grams. The size of atoms is so small that it is not possible to see them even in the most powerful microscope. If it were possible to arrange atoms in such a way as we pour peas into a glass, i.e. contacting them with each other, then in a very small volume of 1 cubic millimeter about 10,000,000,000,000,000,000,000 atoms would fit.
In total, about a hundred types of atoms are known. The weight of an atom of uranium - one of the heaviest atoms - is about 238 times the weight of the lightest hydrogen atom. Simple substances, i.e. Substances made up of atoms of the same type are called elements.
When combined, atoms form molecules. If a molecule consists of different kinds of atoms, then the substance is called complex. A water molecule, for example, is made up of two hydrogen atoms and one oxygen atom. Just like atoms, molecules are very small. A prime example, indicating the small size of molecules and how many of them are even in a relatively small volume, is an example given by the English physicist Thomson. If we take a glass of water and mark all the molecules of water in this glass in a certain way, and then pour the water into the sea and stir it thoroughly, it turns out that in whatever ocean or sea we draw a glass of water, it will contain about a hundred marked us molecules.
All bodies are clusters of very a large number molecules or atoms. In gases, these particles are in chaotic motion, which has the greater intensity, the higher the temperature of the gas. In liquids, the cohesive forces between individual molecules are much greater than in gases. Therefore, although the molecules of the liquid are also in motion, they can no longer break away from each other. Solids are built from atoms. The forces of attraction between the atoms of a solid body are much greater, not only in comparison with the forces of attraction between gas molecules, but not in comparison with the molecules of a liquid. As a result, the atoms of a solid body perform only oscillatory motions around more or less unchanged equilibrium positions. The higher the body temperature, the greater the kinetic energy of atoms and molecules. Strictly speaking, it is the kinetic energy of atoms and molecules that determines the temperature.
As for the assumption that the atom is indivisible, that it is supposedly the smallest particle of matter, this assumption was subsequently rejected. Physicists now have a unified point of view, which is that the atom is not indivisible, that it consists of even smaller particles of matter. Moreover, this point of view of physicists is now confirmed with the help of experiments. So, the atom, in turn, is a complex particle consisting of protons, neutrons and electrons. Protons and neutrons form the nucleus of an atom surrounded by electron shell. Almost all the mass of an atom is concentrated in its nucleus. The smallest of all atomic nuclei- the nucleus of a hydrogen atom, consisting of only one proton - has a mass that is 1,850 times greater than the mass of an electron. The masses of the proton and neutron are approximately equal to each other. Thus, the mass of an atom is determined by the mass of its nucleus, or, in other words, by the number of protons and neutrons. Protons have a positive electrical charge, electrons have a negative charge, and neutrons do not. electric charge. The nuclear charge is therefore always positive and equal to the number of protons. This value is called the ordinal number of the element in periodic system D. I. Mendeleev. Usually the number of electrons that make up the shell is equal to the number of protons, and since the charge of the electrons is negative, the atom as a whole is electrically neutral.
Despite the fact that the volume of an atom is very small, the nucleus and the electrons surrounding it occupy only a small fraction of this volume. One can therefore imagine what a colossal density the nuclei of atoms have. If it were possible to place the hydrogen nuclei in such a way that they densely fill the volume of only 1 cubic centimeter, then their weight would be approximately 100 million tons.
Having briefly outlined some of the provisions on the structure of matter and recalling once again that chemical energy is the energy accumulated inside molecules, we can finally move on to presenting the two important considerations promised earlier, which more fully reveal the essence of chemical energy.
Above we said that the thermal energy of the body is the sum of the energy of the translational and rotational movements molecules and the energy of attraction or repulsion between them. This definition of thermal energy is not entirely accurate, or better said, not quite complete. In the case when a molecule of a substance (liquid or gas) consists of two or more atoms, then the thermal energy must also include the energy oscillatory motion atoms within a molecule. This conclusion was reached on the basis of the following considerations. Experience shows that the heat capacity of almost all substances increases with increasing temperature. In other words, the amount of heat required to raise the temperature of 1 kilogram of a substance by 1 °C is, as a rule, the greater, the greater the temperature of this substance. Most gases follow this rule. What explains this? Modern physics answers this question as follows: the main reason for the increase in the heat capacity of a gas with increasing temperature is the rapid increase in the vibrational energy of the atoms that make up the gas molecule as the temperature increases. This explanation is confirmed by the fact that the heat capacity increases with increasing temperature, the more atoms a gas molecule consists of. The heat capacity of monatomic gases, i.e., gases, the smallest particles of which are atoms, in general, almost does not change with increasing temperature.
But if the energy of the vibrational motion of atoms inside the molecule changes, and even very significantly, when the gas is heated, which occurs without changing the chemical composition of this gas, then, apparently, this energy cannot be considered as chemical energy. But what about the above definition of chemical energy, according to which it is the energy accumulated inside the molecule?
This question is quite appropriate. The above definition of chemical energy must be clarified first: chemical energy does not include all the energy accumulated inside the molecule, but only that part of it that can be changed only through chemical transformations.
The second consideration concerning the essence of chemical energy is as follows. Not all of the energy accumulated inside a molecule can be released as a result of a chemical reaction. Part of the energy, and a very large one at that, does not change in any way as a result of the chemical process. It is the energy contained within the atom, or more precisely, within the nucleus of the atom. It is called atomic or nuclear energy. Strictly speaking, this is not surprising. Perhaps, even on the basis of all that has been said above, this circumstance could have been foreseen. Indeed, with the help of any chemical reaction it is impossible to turn one element into another, atoms of one kind into atoms of another kind. In the past, alchemists set themselves such a task, striving at all costs to turn other metals, such as mercury, into gold. The alchemists failed to achieve success in this matter. But if with the help of a chemical reaction it was not possible to turn one element into another, atoms of one type into atoms of another type, then this means that the atoms themselves, or rather their main parts - the nuclei - remain unchanged during the chemical reaction. Therefore, it is not possible to release that very large energy that is accumulated in the nuclei of atoms. And this energy is really very great. At present, physicists have learned how to release the nuclear energy of the atoms of uranium and some other elements. This means that it became possible to turn one element into another. The separation of uranium atoms, taken in an amount of only 1 gram, releases about 10 million calories of heat. To obtain such an amount of heat, it would be necessary to burn about one and a half tons of good coal. One can imagine what great possibilities lie in the use of nuclear (atomic) energy.
Since the transformation of atoms of one type into atoms of another type and the release of nuclear energy associated with such a transformation is no longer part of the task of chemistry, nuclear energy is not included in the composition of the chemical energy of matter.
So, the chemical energy of plants, which is, as it were, canned solar energy, may be released and used at our discretion. In order to release the chemical energy of a substance, converting it at least partially into other types of energy, it is necessary to organize such a chemical process, as a result of which such substances would be obtained, the chemical energy of which would be less than the chemical energy of the initially taken substances. In this case, part of the chemical energy can be converted into heat, and this latter is used in a thermal power plant with the ultimate goal of obtaining electrical energy.
With regard to firewood - vegetable fuel - such a suitable chemical process is the combustion process. The reader is certainly familiar with it. Therefore, we recall only briefly that the combustion or oxidation of a substance is the chemical process of combining this substance with oxygen. As a result of the combination of a burning substance with oxygen, a significant amount of chemical energy is released - heat is released. Heat is released not only during the combustion of firewood, but also during any other combustion or oxidation process. It is well known, for example, how much heat is released when straw or coal is burned. In our body, too, there is a slow process of oxidation and therefore the temperature inside the body is slightly higher than the temperature of the environment that usually surrounds us. The rusting of iron is also an oxidation process. Heat is also released here, but only this process proceeds so slowly that we practically do not notice heating.
At present, firewood is almost not used in industry. Forests are too important for human life to be able to burn firewood in the furnaces of steam boilers in factories, factories and power stations. And not for a long time would be enough all the forest resources on earth, if they decided to use them for this purpose. In our country, a completely different work is being carried out: mass planting of windbreaks and forest areas is carried out to improve climatic conditions terrain.
However, everything said above about the formation of plant tissues due to the energy of sunlight and about the use of the chemical energy of plant tissues to produce heat is most directly related to those fuels that are widely used in our time in industry and, in particular, at thermal power stations. These fuels primarily include: peat, brown coal and hard coal. All these fuels are decomposition products of dead plants, in most cases without air access or with little air access. Such conditions for the dying parts of plants are created in the water, under a layer of water sediments. Therefore, the formation of these fuels occurred most often in swamps, in often flooded lowlands, in shallowing or completely drying up rivers and lakes.
Of the three fuels listed above, peat is the youngest in origin. It contains a large number of plant parts. The quality of a particular fuel is largely characterized by its calorific value. The calorific value, or calorific value, is the amount of heat, measured in calories, that is released when 1 kilogram of fuel is burned. If we had at our disposal dry peat that does not contain moisture, then its calorific value would be slightly higher than the calorific value of firewood: dry peat has a calorific value of about 5,500 calories per 1 kilogram, and firewood - about 4,500. , usually contains quite a lot of moisture and therefore has a lower calorific value. The use of peat at Russian power plants began in 1914, when a power plant was built, bearing the name of the outstanding Russian engineer R. E. Klasson, the founder of a new method of peat extraction, the so-called hydraulic method. After the Great October Socialist Revolution, the use of peat in power plants became widespread. Russian engineers have developed the most rational methods for extracting and burning this cheap fuel, whose deposits in Russia are very significant, as well as the production of air ducts.
An older decomposition product of plant tissues than peat is the so-called brown coal. However, brown coal still contains plant cells and parts of plants. Dry brown coal with a low content of non-combustible impurities - ash - has a calorific value of over 6,000 calories per 1 kilogram, i.e., even higher than firewood and dry peat. In fact, brown coal is a fuel with a much lower calorific value due to significant moisture content, and often high ash content. Currently, brown coal is one of the most commonly used fuels for. Its deposits in our country are very large.
As for such valuable fuels as oil and natural gas, they are almost never used on. As already mentioned, in our country the use of fuel reserves is carried out taking into account the interests of all industries, planned and economically. Unlike Western countries, in Russia, power plants burn mainly low-grade fuels that are not very suitable for other purposes. At the same time, power plants, as a rule, are built in areas where fuel is extracted, which excludes its long-distance transportation. Soviet power engineers had to work hard to build such devices for burning fuel - furnaces, which would allow the use of low-grade, wet fuel.
