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 of 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. It takes a lot of energy to break the hydrogen bonds that hold water molecules together. 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 the physical properties of 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. When acidity (the concentration of H ions) increases, the free anions that come 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 the environment, being part of 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
1. What is a chemical element?
Answer. A chemical element is a collection of atoms with the same nuclear charge and the number of protons that matches the ordinal (atomic) number in the periodic table. Each chemical element has its own name and symbol, which are given in the Periodic Table of the Elements of Dmitry Ivanovich Mendeleev
2. How many chemical elements are currently known?
Answer. About 90 chemical elements have been identified in nature. Why about? Because among the elements with an atomic number less than 92 (up to uranium), technetium (43) and francium (87) are absent in nature. Virtually no astatine (85). On the other hand, both neptunium (93) and plutonium (94) (unstable transuranium elements) are found in nature where uranium ores are found. All elements after plutonium Pu in Mendeleev's periodic system are completely absent in the earth's crust, although some of them are undoubtedly formed in space during supernova explosions. But they don't last long...
To date, scientists have synthesized 26 transuranium elements, starting with neptunium (N=93) and ending with element number N=118 (the element number corresponds to the number of protons in the atomic nucleus and the number of electrons around the atomic nucleus).
Transuranium chemical elements from 93 to 100 are obtained in nuclear reactors, and the rest - as a result of nuclear reactions in particle accelerators.
3. What substances are called inorganic?
Answer. Inorganic substances (inorganic compounds) - chemical compounds that are not organic, that is, do not contain carbon, as well as some carbon-containing compounds (carbides, cyanides, carbonates, carbon oxides and some other substances that are traditionally classified as inorganic). Inorganic substances do not have a carbon skeleton characteristic of organic substances.
4. What compounds are called organic?
Answer. Organic compounds, organic substances - a class of chemical compounds that include carbon (with the exception of carbides, carbonic acid, carbonates, carbon oxides and cyanides). Organic compounds, in addition to carbon, most often contain the elements hydrogen, oxygen, nitrogen, much less often - sulfur, phosphorus, halogens and some metals (separately or in various combinations).
5. What chemical bonds are called covalent?
Answer. Covalent bond (atomic bond, homeopolar bond) - a chemical bond formed by the overlap (socialization) of a pair of valence electron clouds. The electron clouds (electrons) that provide communication are called a common electron pair.
The characteristic properties of a covalent bond - directionality, saturation, polarity, polarizability - determine the chemical and physical properties of compounds.
The direction of the bond is due to the molecular structure of the substance and the geometric shape of their molecule. The angles between two bonds are called bond angles.
Saturation - the ability of atoms to form a limited number of covalent bonds. The number of bonds formed by an atom is limited by the number of its outer atomic orbitals.
The polarity of the bond is due to the uneven distribution of the electron density due to differences in the electronegativity of the atoms. On this basis, covalent bonds are divided into non-polar and polar.
The polarizability of a bond is expressed in the displacement of bond electrons under the influence of an external electric field, including that of another reacting particle. Polarizability is determined by the electron mobility. The polarity and polarizability of covalent bonds determine the reactivity of molecules with respect to polar reagents.
Questions after §6
1. 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?
Answer. Chemical elements of the cell. The chemical composition of cells of different organisms, and even cells that perform different functions in one multicellular organism, can differ significantly from each other. At the same time, different cells include practically the same chemical elements. The similarity of the elementary chemical composition of the cells of different organisms proves the unity of living nature. At the same time, there is not a single chemical element contained in living organisms that would not be found in the bodies of inanimate nature. This indicates the commonality of animate and inanimate nature.
2. What elements are macronutrients?
Answer. Macronutrients - chemical elements contained in the body of living organisms in concentrations from 0.001% to 70%. Macronutrients include: oxygen, hydrogen, carbon, nitrogen, phosphorus, potassium, calcium, sulfur, magnesium, sodium, chlorine, iron, etc.
3. What is the difference between micronutrients and ultramicronutrients?
Answer. The main difference is in the percentage: for macronutrients more than 0.01%, for micronutrients - less than 0.001%. Ultramicroelements are contained in an even smaller volume - less than 0.0000001%. Ultramicroelements include gold, silver, mercury, platinum, cesium, and selenium. The functions of ultramicronutrients are currently little understood. Microelements include bromine, iron, iodine, cobalt, manganese, copper, molybdenum, selenium, fluorine, chromium, zinc. The lower the concentration of a substance in the body, the more difficult it is to determine its biological role.
4. Why is it believed that carbon is the chemical basis of life?
Answer. Carbon has unique chemical properties fundamental to life. The combination of the properties of an atom - the size and number of unpaired electrons in the outer orbital, allows the formation of various organic compounds. molecules. They form complex chemical compounds that differ in structure and function.
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 different functions, can 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 is the chemical basis of 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.
Question 1. What is the similarity of biological systems and objects of inanimate nature?
The main similarity is the relationship of the chemical composition. The vast majority of chemical elements known today are found both in living organisms and in inanimate nature. There are no atoms that are unique to living systems. However, the content of specific elements in animate and inanimate nature differs sharply. Organisms (from bacteria to vertebrates) are able to selectively accumulate elements that are necessary for life.
However, it is possible to single out a set of properties that are inherent in all living beings and distinguish them from bodies of inanimate nature. Living objects are characterized by a special form of interaction with the environment - metabolism. It is based on interconnected and balanced processes of assimilation (anabolism) and dissimilation (catabolism). These processes are aimed at updating the structures of the body, as well as providing various aspects of its life with the necessary nutrients and energy. An indispensable condition for metabolism is the supply of certain chemical compounds from outside, i.e., the existence of an organism as an open system.
It is interesting that inanimate objects can exhibit individual properties that are more characteristic of living things. So, crystals of minerals are capable of growth and metabolism with the environment, and phosphorus can "store" the energy of light. But not a single inorganic system possesses the whole set of features inherent in a living organism.
Question 2. List bioelements and explain what is their significance in the formation of living matter.
Bioelements (organogens) include oxygen, carbon, hydrogen, nitrogen, phosphorus and sulfur. They form the basis of proteins, lipids, carbohydrates, nucleic acids and other organic substances. For all organic molecules, the carbon atoms that form the framework are of particular importance. A variety of chemical groups formed by other bioelements are attached to this framework. Depending on the composition and arrangement of such groups, organic molecules acquire individual properties and functions. For example, amino acids contain nitrogen in large quantities, and nucleic acids contain phosphorus.
In the cells of some organisms, an increased content of certain chemical elements was found. For example, bacteria are able to accumulate manganese, seaweed - iodine, duckweed - radium, mollusks and crustaceans - copper, vertebrates - iron.
Chemical elements are part of organic compounds. Carbon, oxygen and hydrogen are involved in the construction of carbohydrate and fat molecules. In addition to these elements, protein molecules include nitrogen and sulfur, and nucleic acid molecules include phosphorus and nitrogen. Iron and copper ions are included in the molecules of oxidative enzymes, magnesium is included in the chlorophyll molecule, iron is part of hemoglobin, iodine is part of the thyroid hormone - thyroxine, zinc is part of insulin - the pancreatic hormone, cobalt is part of vitamin B 12.
Chemical elements that take part in metabolic processes and have a pronounced biological activity are called biogenic.
Question 3. What are trace elements? Give examples and describe the biological significance of these elements.
Many chemical elements are contained in living systems in very small quantities (fractions of a percent of the total mass). Such substances are called trace elements.
Trace elements: Cu, B, Co, Mo, Mn, Ni, Br, T.p. I and others. Their share in the cell in total accounts for more than 0.1%; the concentration of each does not exceed 0.001%. These are metal ions that are part of biologically active substances (hormones, enzymes, etc.). Plants, fungi, bacteria receive trace elements from soil and water; animals - mostly with food. For the most part, microelements are part of proteins and biologically active substances (hormones, vitamins). For example, zinc is found in the pancreatic hormone insulin, and iodine is found in thyroxine (thyroid hormone). Cobalt is the most important component of vitamin B 12. Iron is part of about seventy body proteins, copper is part of twenty proteins, etc.
In the cells of some organisms, an increased content of certain chemical elements was found. For example, bacteria are able to accumulate manganese, seaweed - iodine, duckweed - radium, mollusks and crustaceans - copper, vertebrates - iron. Ultramicroelements: uranium, gold, beryllium, mercury, cesium, selenium and others. Their concentration does not exceed 0.000001%. The physiological role of many of them has not been established.
Question 4. How will the lack of any microelement affect the life of the cell and organism? Give examples of such phenomena.
The lack of any microelement leads to a decrease in the synthesis of the organic matter in which this microelement is included. As a result, the processes of growth, metabolism, reproduction, etc. are disrupted. For example, iodine deficiency in food leads to a general drop in body activity and an overgrowth of the thyroid gland - endemic goiter. Boron deficiency causes the death of apical buds in plants. The main function of iron in the body is the transport of oxygen and participation in oxidative processes (through dozens of oxidative enzymes). Iron is part of hemoglobin, myoglobin, cytochromes. Iron plays an important role in the processes of energy release, in providing immune responses of the body, in the metabolism of cholesterol. With a lack of zinc, cell differentiation, insulin production, absorption of vitamin E are disrupted, skin cell regeneration is disrupted. Zinc plays an important role in the processing of alcohol, so its deficiency in the body causes a predisposition to alcoholism (especially in children and adolescents). Zinc is part of insulin. a number of enzymes involved in hematopoiesis.
Selenium deficiency can lead to cancer in humans and animals. By analogy with avitaminosis, such diseases are called microelementoses.
Question 5. Tell us about ultramicronutrients. What is their content in the body? What is known about their role in living organisms?
Ultramicroelements- these are elements that are contained in the cell in negligible quantities (the concentration of each does not exceed one millionth of a percent). These include uranium, radium, gold, silver, mercury, beryllium, arsenic, etc.
Arsenic is classified as conditionally essential, immunotoxic elements. It is known that arsenic with proteins (cysteine, glutamine), lipoic acid. Arsenic affects the oxidative processes in mitochondria and takes part in many other important biological processes, it is part of the enzymes that protect the membranes of our cells from oxidation, and is necessary for their normal operation.
In the body, lithium promotes the release of magnesium from cellular "depots" and inhibits the transmission of nerve impulses, thereby reducing. excitability of the nervous system. lithium also affects neuroendocrine processes, fat and carbohydrate metabolism.
Vanadium is involved in the regulation of carbohydrate metabolism and the cardiovascular system and is also involved in the metabolism of bone and tooth tissues. The physiological role of most of the ultraelements has not been established. It is possible that it is absent at all, and then part of the ultramicroelements are simply impurities of living organisms. Many ultramicroelements are toxic to humans and animals in certain concentrations, for example, silver, titanium, arsenic, etc.
Question 6. Give examples of biochemical endemics known to you. Explain the reasons for their origin.
Biochemical endemic- These are diseases of plants, animals and humans associated with a clear deficiency or excess of any chemical element in the environment. As a result, microelementoses or some other disorders develop. So, in many regions of our country, the amount of iodine in water and soil is significantly reduced. Lack of iodine leads to a drop in the synthesis of the hormone thyroxin, the thyroid gland, trying to compensate for its lack, grows (endemic goiter develops). Other examples are selenium deficiency in the soil of some regions of Mongolia, as well as an excess of mercury in the water of some mountain rivers in Chile and Ceylon. There is an excess of fluoride in the water of many areas, which leads to dental disease - fluorosis.
One of the forms of biochemical endemia can be considered an excess of radioactive elements in the area of the Chernobyl nuclear power plant and places subjected to intense radio exposure, for example,
