Not organic matter, included in the cell
The purpose of the lesson: study the chemical composition of the cell, identify the role of inorganic substances.
Lesson objectives:
educational: show diversity chemical elements and compounds that make up living organisms, their significance in the process of life;
developing: continue to develop skills and abilities independent work with a textbook, the ability to highlight the main points, formulate conclusions;
educational: cultivate a responsible attitude towards completing assigned tasks.
Equipment: multimedia projector, presentation, Handout.
Lesson Plan
I. Organizational moment.
Greetings; – preparing the audience for work; – availability of students.
II. Motivation for learning activities.
– Here is a set of words: copper, proteins, iron, carbohydrates, fats, vitamins, magnesium, gold, sulfur, calcium, phosphorus.
– What two groups can these words be divided into according to their meaning? Explain your answer. (Organic and inorganic; chemical substances and chemical elements).
– How many of you can name the role of certain substances or elements in the life of living organisms?
– Set the goal and objectives of our lesson, based on the title of the topic.
III. Presentation of new material.
Presentation. The presentation includes 3 lessons on this topic. We start working with the key second slide: follow the hyperlink to the right lesson.
3rd slide: conversation according to the scheme “Content of chemical elements in the human body.”:
– The cell contains about 80 different chemical elements that are found in inanimate objects. What does this mean? (about the commonality of living and inanimate nature). 27 elements fulfill certain functions, the rest enter the body with food, water and air.
– Name what chemical elements and in what quantities are contained in the human body?
– All chemical compounds found in living organisms are divided into groups.
– Using the table, make a diagram “The main groups of chemical elements in nature” (see table “Elements that make up the cells of living organisms”, see Table 1 ). Oxygen, hydrogen, carbon, nitrogen, sulfur and phosphorus are necessary components molecules of biological polymers (proteins, nucleic acids), they are often called bioelements.
Scheme
Slide 5: Start filling out the table - reference summary in your notebook (this table will be supplemented in subsequent lessons, see table 2 ).
- Of all chemical compounds contained in living organisms, water makes up 75–85% of body weight.
– Why is this amount of water needed? What functions does water perform in a living organism?
– You already know that structure and functions are interconnected. Let's take a closer look at the structure of the water molecule to find out why water has these properties. As you explain, you fill out a supporting summary in your notebook (see slide 5).
Slides 6 – 7 demonstrate the structural features of the water molecule and its properties.
- From among not organic compounds, which are part of organisms, highest value have salts mineral acids and the corresponding cations and anions. Although the need of humans and animals for minerals is expressed in tens and even thousandths of a gram, the absence of any biologically important elements leads to serious illnesses.
– Fill out the table, column “Mineral salts”, using the textbook material pp. 104 – 107. ( Slide 8 Click the hyperlink to check the completed work).
– Give examples proving the role of mineral salts in the life of living organisms.
IV. Consolidating new material:
several students (how many computers are in the classroom) take an interactive test 1 “ Inorganic substances cells”;
the rest do tasks for training thinking and the ability to draw conclusions(Handout) :
There is a certain connection between the first two terms. There is the same connection between the fourth and one of the concepts below. Find it:
1. Iodine: thyroid gland = fluoride: ___________________
a) Pancreas b) tooth enamel c) nucleic acid d) adrenal glands
2. Iron: hemoglobin = __________: chlorophyll:
a) cobalt b) copper c) iodine d) magnesium
3. Execute digital dictation"Molecules". 1. Hydrogen bonds are the weakest bonds in a molecule (1). 2. Structure and composition are one and the same (0). 3. Composition always determines structure (0). 4. The composition and structure of a molecule determine its properties (1). 5. The polarity of water molecules explains its ability to slowly heat up and cool down (0). 6. The oxygen atom in a water molecule carries a positive charge. (0)
V. Lesson summary.
– Have you fulfilled the goals and objectives of the lesson? What new things did you discover in this lesson?
Literature:
Biology. 9th grade: lesson plans based on the textbook by S.G. Mamontov, V.B. Zakharov, N.I. Sonin / author. – comp. M.M.Gumenyuk. Volgograd: Teacher, 2006.
Lerner G.I. General biology. Lesson tests and assignments. 10 – 11 grades/ – M.: Aquarium, 1998.
Mamontov S.G., Zakharov V.B., Sonin N.I. Biology. General patterns. 9th grade: Textbook. for general education textbook establishments. – M.: Bustard, 2000.
CD Digital Set educational resources to the textbook Teremov A.V., Petrosova R.A., Nikishov A.I. Biology. General patterns of life: 9th grade. humanit ed. VLADOS Center, 2003. Physikon LLC, 2007.
Textbook for grades 10-11
Section I. Cell - a unit of living things
Chapter I. Chemical composition of the cell
Living organisms contain a large number of chemical elements. They form two classes of compounds - organic and inorganic. Chemical compounds whose structure is based on carbon atoms make up hallmark alive. These compounds are called organic. Organic compounds are extremely diverse, but only four classes have universal biological significance: proteins, nucleic acids, carbohydrates and lipids.
§ 1. Inorganic compounds
Biologically important chemical elements. Of the more than 100 chemical elements known to us, about 80 are included in living organisms, and only 24 are known what functions they perform in the cell. The set of these elements is not accidental. Life originated in the waters of the World Ocean, and living organisms consist primarily of those elements that form compounds that are easily soluble in water. Most of these elements are light; their peculiarity is the ability to form strong (covalent) bonds and form many different complex molecules.
As part of cells human body Oxygen (more than 60%), carbon (about 20%) and hydrogen (about 10%) predominate. Nitrogen, calcium, phosphorus, chlorine, potassium, sulfur, sodium, magnesium taken together account for about 5%. The remaining 13 elements make up no more than 0.1%. The cells of most animals have a similar elemental composition; Only the cells of plants and microorganisms differ. Even those elements that are contained in cells in negligible quantities cannot be replaced by anything and are absolutely necessary for life. Thus, the iodine content in cells does not exceed 0.01%. However, if there is a lack of it in the soil (because of this and in food products) the growth and development of children is delayed. The copper content in animal cells does not exceed 0.0002%. But with a lack of copper in the soil (hence in plants), massive diseases of farm animals occur.
The meaning for the basic element cell is given at the end of this paragraph.
Inorganic (mineral) compounds. Living cells contain a number of relatively simple connections, which are also found in inanimate nature- in minerals, natural waters. These are inorganic compounds.
Water is one of the most common substances on Earth. She covers most earth's surface. Almost all living things are composed primarily of water. In humans, the water content in organs and tissues varies from 20% (in bone tissue) to 85% (in the brain). About 2/3 of a person’s mass is water, in the body of a jellyfish up to 95% is water, even in dry plant seeds, water is 10-12%.
Water has some unique properties. These properties are so important for living organisms that it is impossible to imagine life without this compound of hydrogen and oxygen.
The unique properties of water are determined by the structure of its molecules. In a water molecule, one oxygen atom is covalently bonded to two hydrogen atoms (Fig. 1). The water molecule is polar (dipole). Positive charges concentrated at hydrogen atoms, since oxygen is more electronegative than hydrogen.
Rice. 1. Formation of hydrogen bonds in water
The negatively charged oxygen atom of one water molecule is attracted to the positively charged hydrogen atom of another molecule to form a hydrogen bond (Figure 1).
The strength of a hydrogen bond is approximately 15-20 times weaker than a covalent bond. Therefore, the hydrogen bond is easily broken, which is observed, for example, during the evaporation of water. Due to thermal movement molecules in water, some hydrogen bonds are broken, others are formed.
Thus, in liquid water the molecules are mobile, which is important for metabolic processes. Water molecules easily penetrate cell membranes.
Due to the high polarity of its molecules, water is a solvent for other polar compounds. More substances dissolve in water than in any other liquid. That is why in aquatic environment cells carried many chemical reactions. Water dissolves metabolic products and removes them from the cell and the body as a whole.
Water has high heat capacity, i.e. the ability to absorb heat with a minimal change in its own temperature. Thanks to this, it protects the cell from sudden changes temperature. Since a lot of heat is consumed to evaporate water, by evaporating water, organisms can protect themselves from overheating (for example, when sweating).
Water has high thermal conductivity. This property makes it possible uniform distribution warmth between body tissues.
Water serves as a solvent for “lubricants”, which are needed wherever there are rubbing surfaces (for example, in joints).
Water has maximum density at 4°C. Therefore, ice, which has a lower density, is lighter than water and floats on its surface, which protects the reservoir from freezing.
In relation to water, all cell substances are divided into two groups: hydrophilic - “ water lovers“and hydrophobic - “afraid of water” (from the Greek “hydro” - water, “phileo” - to love and “phobos” - fear).
Hydrophilic substances include substances that are highly soluble in water. These are salts, sugars, amino acids. Hydrophobic substances, on the contrary, are practically insoluble in water. These include, for example, fats.
Cell surfaces that separate the cell from external environment, and some other structures consist of water-insoluble (hydrophobic) compounds. Thanks to this, the structural integrity of the cell is maintained. A cell can be figuratively represented as a vessel with water, where biochemical reactions take place that ensure life. The walls of this vessel are insoluble in water. However, they are capable of selectively permeating water-soluble compounds.
In addition to water, among the inorganic substances of the cell we should mention salts, which are ionic compounds. They are formed by cations of potassium, sodium, magnesium and other metals and anions of hydrochloric, carbonic, sulfuric, and phosphoric acids. When such salts dissociate, cations (K +, Na +, Ca 2+, Mg 2+, etc.) and anions (CI -, HCO 3 -, HS0 4 -, etc.) appear in solutions. The concentration of ions on the outer surface of the cell differs from their concentration on inner surface. Different number potassium and sodium ions on the inner and outer surfaces of the cell creates a charge difference on the membrane. On the outer surface cell membrane a very high concentration of sodium ions, and on the inner surface a very high concentration of potassium ions and a low concentration of sodium. As a result, a potential difference is formed between the inner and outer surfaces of the cell membrane, which causes the transmission of excitation along a nerve or muscle.
Calcium and magnesium ions are activators of many enzymes, and if they are deficient, vital functions are impaired. important processes in cells. Row important functions performed in living organisms inorganic acids and their salts. Hydrochloric acid creates an acidic environment in the stomach of animals and humans and in special organs of insectivorous plants, accelerating the digestion of food proteins. Phosphoric acid residues (H 3 P0 4), joining a number of enzymatic and other cell proteins, change their physiological activity. Residues of sulfuric acid, joining foreign substances insoluble in water, give them solubility and thus contribute to their removal from cells and organisms. Sodium and potassium salts of nitrous and phosphoric acids, calcium salt of sulfuric acid serve as important components of the mineral nutrition of plants; they are applied to the soil as fertilizers to feed plants. The meaning of chemical elements for a cell is given in more detail below.
Biologically important chemical elements of the cell
- What is biological role water in the cage?
- What ions are contained in the cell? What is their biological role?
- What role do the cations contained in the cell play?
The cell contains about 70 elements Periodic table Mendeleev's elements, and 24 of them are present in all types of cells. All elements present in the cell are divided, depending on their content in the cell, into groups:
- macronutrients– H, O, N, C,. Mg, Na, Ca, Fe, K, P, Cl, S;
- microelements– B, Ni, Cu, Co, Zn, Mb, etc.;
- ultramicroelements– U, Ra, Au, Pb, Hg, Se, etc.
- organogens(oxygen, hydrogen, carbon, nitrogen),
- macroelements,
- microelements.
Molecules that make up a cell inorganic And organic connections.
Inorganic compounds of the cell
– water And inorganic ions.
Water- the most important inorganic substance of the cell. All biochemical reactions occur in aqueous solutions. The water molecule has a nonlinear spatial structure and has polarity. Hydrogen bonds are formed between individual water molecules, which determine the physical and Chemical properties water.
|
Physical properties of water |
Implications for biological processes |
|
High heat capacity (due to hydrogen bonds between molecules) and thermal conductivity (due to small sizes molecules) |
Transpiration |
|
Transparency in the visible spectrum |
Highly productive biocenoses of ponds, lakes, rivers (due to the possibility of photosynthesis at shallow depths) |
|
Almost complete incompressibility (due to intermolecular cohesion forces) |
Maintaining the shape of organisms: the shape of the succulent organs of plants, the position of herbs in space, the hydrostatic skeleton roundworms, jellyfish, amniotic fluid supports and protects the mammalian fetus |
|
Molecular mobility (due to weak hydrogen bonds) |
Osmosis: the flow of water from the soil; plasmolysis |
|
Viscosity (hydrogen bonds) |
Lubricating properties: synovial fluid in joints, pleural fluid |
|
Solvent (molecular polarity) |
Blood, tissue fluid, lymph, gastric juice, saliva, in animals; cell sap in plants; aquatic organisms use oxygen dissolved in water |
|
The ability to form a hydration shell around macromolecules (due to the polarity of the molecules) |
Dispersive medium in colloidal system cytoplasm |
|
Optimal for biological systems meaning of forces surface tension(due to intermolecular cohesion forces) |
Aqueous solutions are a means of transporting substances in the body |
|
Expansion upon freezing (due to the formation of a maximum number of 4 hydrogen bonds by each molecule) |
Ice is lighter than water and acts as a heat insulator in reservoirs. |
Inorganic ions:
cations K+, Na+, Ca2+, Mg2+ and anions Cl–, NO3-, PO4 2-, CO32-, HPO42-.
The difference between the number of cations and anions (Nа +
, TO +
, Cl-) on the surface and inside the cell ensures the occurrence of an action potential, which underlies nervous and muscle stimulation.
Phosphoric acid anions create phosphate buffer system, maintaining the pH of the intracellular environment of the body at a level of 6-9.
Carbonic acid and its anions create bicarbonate buffer system and maintain the pH of the extracellular environment (blood plasma) at a level of 7-4.
Nitrogen compounds serve source mineral nutrition, protein synthesis, nucleic acids.
Phosphorus atoms are part of nucleic acids, phospholipids, as well as the bones of vertebrates and the chitinous cover of arthropods.
Calcium ions are part of the substance of bones; they are also necessary for muscle contraction and blood clotting.
Table. The role of macroelements at the cellular and organismal level of organization.
Table.
Thematic assignments
Part A
A1. The polarity of water determines its ability
1) conduct heat
3) dissolve sodium chloride
2) absorb heat
4) dissolve glycerin
A2. Children with rickets should be given medications containing
1) iron
2) potassium
3) calcium
4) zinc
A3. Carrying out nerve impulse provided by ions:
1) potassium and sodium
2) phosphorus and nitrogen
3) iron and copper
4) oxygen and chlorine
A4. Weak ties between water molecules in its liquid phase are called:
1) covalent
2) hydrophobic
3) hydrogen
4) hydrophilic
A5. Hemoglobin contains
1) phosphorus
2) iron
3) sulfur
4) magnesium
A6. Select a group of chemical elements that are necessarily included in proteins
1) Na, K, O, S
2) N, P, C, Cl
3) C, S, Fe, O
4) C, H, O, N
A7. For patients with hypofunction thyroid gland give medications containing
1) iodine
2) iron
3) phosphorus
4) sodium
Part B
IN 1. Select the functions of water in the cage
1) energy
2) enzymatic
3) transport
4) construction
5) lubricating
6) thermoregulatory
AT 2. Select only physical properties water
1) ability to dissociate
2) hydrolysis of salts
3) density
4) thermal conductivity
5) electrical conductivity
6) electron donation
Part C
C1. What physical properties of water determine its biological significance?
A cell is an elementary unit of a living thing, possessing all the characteristics of an organism: the ability to reproduce, grow, exchange substances and energy with the environment, irritability, and the constancy of chemical output.
Macroelements are elements whose amount in a cell is up to 0.001% of body weight. Examples are oxygen, carbon, nitrogen, phosphorus, hydrogen, sulfur, iron, sodium, calcium, etc.
Microelements are elements whose amount in a cell ranges from 0.001% to 0.000001% of body weight. Examples are boron, copper, cobalt, zinc, iodine, etc.
Ultramicroelements are elements whose content in a cell does not exceed 0.000001% of body weight. Examples are gold, mercury, cesium, selenium, etc.
2. Make a diagram of “Cell Substances”.
3. What does it say? scientific fact similarities between the elementary chemical composition of living and nonliving nature?
This indicates the commonality of living and inanimate nature.
Inorganic substances. The role of water and minerals in cell life.
1. Give definitions of concepts.
Inorganic substances are water, mineral salts, acids, anions and cations present in both living and non-living organisms.
Water is one of the most common inorganic substances in nature, the molecule of which consists of two hydrogen atoms and one oxygen atom.
2. Draw a diagram of the “Structure of Water”.
3. What structural features of water molecules give it unique properties, without which life is impossible?
The structure of the water molecule is formed by two hydrogen atoms and one oxygen atom, which form a dipole, that is, water has two polarities “+” and “-”. This contributes to its permeability through the membrane walls, the ability to dissolve chemicals. In addition, water dipoles are associated hydrogen bonds with each other, which ensures its ability to be in different states of aggregation, and also - to dissolve or not to dissolve various substances.
4. Fill out the table “The role of water and minerals in the cell.”
5. What is the meaning relative constancy internal environment cells in ensuring the processes of its life?
The constancy of the internal environment of the cell is called homeostasis. Violation of homeostasis leads to damage to the cell or to its death, plastic metabolism and energy exchange are constantly occurring in the cell, these are two components of metabolism, and disruption of this process leads to damage or death of the entire organism.
6. What is the purpose of buffer systems of living organisms and what is the principle of their functioning?
Buffer systems maintain a certain pH value (an indicator of acidity) of the medium in biological fluids. The principle of operation is that the pH of the medium depends on the concentration of protons in this medium (H+). The buffer system is capable of absorbing or donating protons depending on their entry into the environment from the outside or, conversely, removal from the environment, while the pH will not change. The presence of buffer systems is necessary in a living organism, since due to changing conditions environment pH can vary greatly, and most enzymes only work when a certain value pH.
Examples of buffer systems:
carbonate-hydrocarbonate (mixture of Na2СО3 and NaHCO3)
phosphate (mixture of K2HPO4 and KH2PO4).
Organic substances. The role of carbohydrates, lipids and proteins in cell life.
1. Give definitions of concepts.
Organic substances are substances that necessarily contain carbon; they are part of living organisms and are formed only with their participation.
Proteins are high molecular weight organic substances consisting of alpha amino acids linked into a chain by a peptide bond.
Lipids are a large group of natural organic compounds, including fats and fat-like substances. The molecules of simple lipids consist of alcohol and fatty acids, complex ones - of alcohol, high-molecular fatty acids and other components.
Carbohydrates are organic substances containing carbonyl and several hydroxyl groups and are otherwise called sugars.
2. Fill in the table with the missing information “Structure and functions of organic substances of the cell.”
3. What is meant by protein denaturation?
Protein denaturation is the loss of a protein's natural structure.
Nucleic acids, ATP and other organic compounds of the cell.
1. Give definitions of concepts.
Nucleic acids are biopolymers consisting of monomers - nucleotides.
ATP is a compound consisting of the nitrogenous base adenine, the carbohydrate ribose and three phosphoric acid residues.
A nucleotide is a nucleic acid monomer that consists of a phosphate group, a five-carbon sugar (pentose) and a nitrogenous base.
A macroergic bond is a bond between phosphoric acid residues in ATP.
Complementarity is the spatial mutual correspondence of nucleotides.
2. Prove that nucleic acids are biopolymers.
Nucleic acids are made up of large quantity repeating nucleotides and have a mass of 10,000 to several million carbon units.
3. Describe the structural features of the nucleotide molecule.
A nucleotide is a compound of three components: a phosphoric acid residue, a five-carbon sugar (ribose), and one of the nitrogenous compounds (adenine, guanine, cytosine, thymine or uracil).
4. What is the structure of the DNA molecule?
DNA is a double helix consisting of many nucleotides that are sequentially connected to each other by covalent bonds between the deoxyribose of one nucleotide and the phosphoric acid residue of another nucleotide. The nitrogenous bases, which are located on one side of the backbone of one chain, are connected by H-bonds to the nitrogenous bases of the second chain according to the principle of complementarity.
5. Applying the principle of complementarity, construct the second strand of DNA.
T-A-T-C-A-G-A-C-C-T-A-C
A-T-A-G-T-C-T-G-G-A-T-G.
6. What are the main functions of DNA in a cell?
With the help of four types of nucleotides, everything is written in DNA important information in a cell about an organism, which is passed on to subsequent generations.
7. How does an RNA molecule differ from a DNA molecule?
RNA is a single strand smaller than DNA. Nucleotides contain the sugar ribose, not deoxyribose, as in DNA. The nitrogenous base, instead of thymine, is uracil.
8. What do the structures of DNA and RNA molecules have in common?
Both RNA and DNA are biopolymers made up of nucleotides. What nucleotides have in common in structure is the presence of a phosphoric acid residue and the bases adenine, guanine, and cytosine.
9. Complete the table “Types of RNA and their functions in the cell.”
10. What is ATP? What is its role in the cell?
ATP – adenosine triphosphate, a high-energy compound. Its functions are the universal storer and carrier of energy in the cell.
11. What is the structure of the ATP molecule?
ATP consists of three phosphoric acid residues, ribose and adenine.
12. What are vitamins? Which two large groups are they separated?
Vitamins are biologically active organic compounds that play important role in metabolic processes. They are divided into water-soluble (C, B1, B2, etc.) and fat-soluble (A, E, etc.).
13. Fill out the table “Vitamins and their role in the human body.”
Plant and animal cells contain inorganic and organic substances. Inorganic include water and minerals. Organic substances include proteins, fats, carbohydrates, and nucleic acids.
Inorganic substances
Wateris a connection that living cell contains in the greatest number. Water makes up about 70% of the cell's mass. Most intracellular reactions occur in an aqueous environment. Water in the cell is free and bound state.
The importance of water for the life of a cell is determined by its structure and properties. The water content in cells can vary. 95% of water is free in the cell. It is necessary as a solvent for organic and inorganic substances. All biochemical reactions in a cell occur with the participation of water. Water is used for excretion various substances from the cell. Water has high thermal conductivity and prevents sudden temperature fluctuations. 5% of water is in a bound state, forming weak compounds with proteins.
Minerals in the cell they can be in a dissociated state or in combination with organic substances.
Chemical elements, which participate in metabolic processes and have biological activity, are called biogenic.
Cytoplasmcontains about 70% oxygen, 18% carbon, 10% hydrogen, calcium, nitrogen, potassium, phosphorus, magnesium, sulfur, chlorine, sodium, aluminum, iron. These elements make up 99.99% of the composition of the cell and are called macroelements. For example, calcium and phosphorus are part of bones. Iron - component hemoglobin.
Manganese, boron, copper, zinc, iodine, cobalt - microelements. They make up thousandths of a percent of the cell mass. Microelements are needed for the formation of hormones, enzymes, and vitamins. They affect metabolic processes in the body. For example, iodine is part of the thyroid hormone, cobalt is part of vitamin B 12.
Gold, mercury, radium, etc. - ultramicroelements- constitute millionths of a percent of the composition of the cell.
A lack or excess of mineral salts disrupts the vital functions of the body.
Organic matter
Oxygen, hydrogen, carbon, nitrogen are part of organic substances. Organic compounds are large molecules called polymers. Polymers are made up of many repeating units (monomers). Organic polymer compounds include carbohydrates, fats, proteins, nucleic acids, and ATP.
Carbohydrates
Carbohydratesconsist of carbon, hydrogen, oxygen.
Monomerscarbohydrates are monosaccharides. Carbohydrates are divided into monosaccharides, disaccharides and polysaccharides.
Monosaccharides- simple sugars with the formula (CH 2 O) n, where n is any integer from three to seven. Depending on the number of carbon atoms in the molecule, trioses (3C), tetroses (4C), pentoses (5C), hexoses (6C), and heptoses (7C) are distinguished.
TriosesC 3 H 6 O 3 - for example, glyceraldehyde and dihydroxyacetone - play the role of intermediate products in the process of respiration and are involved in photosynthesis. Tetroses C 4 H 8 O 4 are found in bacteria. Pentoses C 5 H 10 O 5 - for example, ribose - is part of RNA, deoxyribose is part of DNA. Hexoses - C 6 H 12 O 6 - for example glucose, fructose, galactose. Glucose is the source of energy for the cell. Together with fructose and galactose, glucose can participate in the formation of disaccharides.
Disaccharidesare formed as a result of a condensation reaction between two monosaccharides (hexoses) with the loss of a water molecule.
The formula of disaccharides is C 12 H 22 O 11 Among the disaccharides, the most widespread are maltose, lactose and sucrose.
Sucrose, or cane sugar, is synthesized in plants. Maltose is formed from starch during its digestion in animals. Lactose, or milk sugar, is found only in milk.
Polysaccharides (simple) are formed as a result of a condensation reaction large number monosaccharides. Simple polysaccharides include starch (synthesized in plants), glycogen (found in liver cells and muscles of animals and humans), cellulose (forms cell wall in plants).
Complex polysaccharides are formed as a result of the interaction of carbohydrates with lipids. For example, glycolipids are part of membranes. Complex polysaccharides also include compounds of carbohydrates with proteins (glycoproteins). For example, glycoproteins are part of the mucus secreted by the glands of the gastrointestinal tract.
Functions of carbohydrates:
1. Energy: The body receives 60% of its energy from the breakdown of carbohydrates. When 1 g of carbohydrates is broken down, 17.6 kJ of energy is released.
2. Structural and support: carbohydrates are included plasma membrane, membranes of plant and bacterial cells.
3. Storage: nutrients (glycogen, starch) are stored in cells.
4. Protective: secretions (mucus) secreted by various glands protect the walls of hollow organs, bronchi, stomach, intestines from mechanical damage, harmful bacteria and viruses.
5. Participate in photosynthesis.
Fats and fat-like substances
Fatsconsist of carbon, hydrogen, oxygen. Monomers fats are fatty acid And glycerol. The properties of fats are determined high-quality composition fatty acids and their quantitative ratio. Vegetable fats are liquid (oils), animal fats are solid (for example, lard). Fats are insoluble in water - they are hydrophobic compounds. Fats combine with proteins to form lipoproteins, and combine with carbohydrates to form glycolipids. Glycolipids and lipoproteins are fat-like substances.
Fat-like substances are part of cell membranes, membrane organelles, nervous tissue. Fats can combine with glucose and form glycosides. For example, digitoxin glycoside is a substance used in the treatment of heart disease.
Functions of fats:
1. Energy: at complete collapse 1 g fat up to carbon dioxide and water, 38.9 kJ of energy is released.
2. Structural: are part of the cell membrane.
3. Protective: a layer of fat protects the body from hypothermia, mechanical shocks and shocks.
4. Regulatory: Steroid hormones regulate metabolic processes and reproduction.
5. Fat- source endogenous water. When 100 g of fat is oxidized, 107 ml of water is released.
Squirrels
Proteins contain carbon, oxygen, hydrogen, and nitrogen. Monomers squirrels are amino acids. Proteins are built from twenty different amino acids. Amino acid formula:
The composition of amino acids includes: NH 2 - an amino group with basic properties; COOH is a carboxyl group, has acid properties. Amino acids differ from each other by their radicals - R. Amino acids are amphoteric compounds. They are connected to each other in the protein molecule using peptide bonds.
Scheme of amino acid condensation (formation of peptide bond)
There are primary, secondary, tertiary and quaternary protein structures. The order, quantity and quality of amino acids that make up a protein molecule determine its primary structure. Proteins with a primary structure can join into a helix using hydrogen bonds and form a secondary structure. Polypeptide chains are twisted in a certain way into a compact structure, forming a globule (ball) - this is the tertiary structure of the protein. Most proteins have a tertiary structure. Amino acids are active only on the surface of the globule. Proteins that have a globular structure combine together to form a quaternary structure. Replacing one amino acid leads to a change in the properties of the protein (Fig. 30).
When exposed to high temperature, acids and other factors, destruction of the protein molecule can occur. This phenomenon is called denaturation (Fig. 31). Sometimes denatured
Rice. thirty.Various structures of protein molecules.
1 - primary; 2 - secondary; 3 - tertiary; 4 - quaternary (using the example of blood hemoglobin).
Rice. 31.Protein denaturation.
1 - protein molecule before denaturation;
2 - denatured protein;
3 - restoration of the original protein molecule.
When conditions change, the bathed protein can again restore its structure. This process is called renaturation and is possible only when the primary structure squirrel.
Proteins can be simple or complex. Simple proteins consist only of amino acids: for example, albumins, globulins, fibrinogen, myosin.
Complex proteins consist of amino acids and other organic compounds: for example, lipoproteins, glycoproteins, nucleoproteins.
Functions of proteins:
1. Energy. The breakdown of 1 g of protein releases 17.6 kJ of energy.
2. Catalytic. Serve as catalysts for biochemical reactions. Catalysts are enzymes. Enzymes speed up biochemical reactions, but are not part of the final products. Enzymes are strictly specific. Each substrate has its own enzyme. The name of the enzyme includes the name of the substrate and the ending “ase”: maltase, ribonuclease. Enzymes are active when certain temperature(35 - 45 O C).
3. Structural. Proteins are part of membranes.
4. Transport. For example, hemoglobin carries oxygen and CO 2 in the blood of vertebrates.
5. Protective. Protecting the body from harmful effects: antibody production.
6. Contractile. Due to the presence of actin and myosin proteins in muscle fibers, muscle contraction occurs.
Nucleic acids
There are two types of nucleic acids: DNA(deoxyribonucleic acid) and RNA(ribonucleic acid). Monomers nucleic acids are nucleotides.
DNA (deoxyribonucleic acid). The DNA nucleotide contains one of the nitrogenous bases: adenine (A), guanine (G), thymine (T) or cytosine (C) (Fig. 32), the carbohydrate deoxyribose and a phosphoric acid residue. The DNA molecule is double helix, built on the principle of complementarity. The following nitrogenous bases are complementary in a DNA molecule: A = T; G = C. Two DNA helices are connected by hydrogen bonds (Fig. 33).
Rice. 32.Nucleotide structure.
Rice. 33.Section of a DNA molecule. Complementary connection of nucleotides of different chains.
DNA is capable of self-duplication (replication) (Fig. 34). Replication begins with the separation of two complementary strands. Each strand is used as a template to form a new DNA molecule. Enzymes are involved in the process of DNA synthesis. Each of the two daughter molecules necessarily includes one old helix and one new one. The new DNA molecule is absolutely identical to the old one in terms of nucleotide sequence. This method of replication ensures accurate reproduction in daughter molecules of the information that was recorded in the mother DNA molecule.
Rice. 34.Duplication of a DNA molecule.
1 - template DNA;
2 - formation of two new chains based on the matrix;
3 - daughter DNA molecules.
Functions of DNA:
1. Storage of hereditary information.
2. Ensuring the transfer of genetic information.
3. Presence in the chromosome as a structural component.
DNA is found in the cell nucleus, as well as in cell organelles such as mitochondria and chloroplasts.
RNA (ribonucleic acid). There are 3 types of ribonucleic acids: ribosomal, transport And informational RNA. An RNA nucleotide consists of one of the nitrogenous bases: adenine (A), guanine (G), cytosine (C), uracil (U), the carbohydrate ribose and a phosphoric acid residue.
Ribosomal RNA (rRNA) in combination with protein it is part of ribosomes. rRNA makes up 80% of all RNA in a cell. Protein synthesis occurs on ribosomes.
Messenger RNA (mRNA) constitutes from 1 to 10% of all RNA in the cell. The structure of mRNA is complementary to the section of the DNA molecule that carries information about synthesis certain protein. The length of the mRNA depends on the length of the DNA section from which the information was read. mRNA carries information about protein synthesis from the nucleus to the cytoplasm to the ribosome.
Transfer RNA (tRNA) makes up about 10% of all RNA. It has a short chain of nucleotides in the shape of a trefoil and is found in the cytoplasm. At one end of the trefoil is a triplet of nucleotides (an anticodon) that codes for a specific amino acid. At the other end is a triplet of nucleotides to which an amino acid is attached. Each amino acid has its own tRNA. tRNA transports amino acids to the site of protein synthesis, i.e. to ribosomes (Fig. 35).
RNA is found in the nucleolus, cytoplasm, ribosomes, mitochondria and plastids.
ATP - Adenazine triphosphoric acid. Adenazine triphosphoric acid (ATP) consists of a nitrogenous base - adenine, sugar - ribose, And three phosphoric acid residues(Fig. 36). The ATP molecule stores a large amount of energy necessary for biochemical processes walking in a cage. ATP synthesis occurs in mitochondria. The ATP molecule is very unstable
active and capable of splitting off one or two phosphate molecules, releasing a large amount of energy. The bonds in an ATP molecule are called macroergic.
ATP → ADP + P + 40 kJ ADP → AMP + P + 40 kJ
Rice. 35. Structure of tRNA.
A, B, C and D - areas of complementary connection within one RNA chain; D - site (active center) of connection with an amino acid; E - site of complementary connection with the molecule.
Rice. 36.The structure of ATP and its conversion to ADP.
Questions for self-control
1. What substances in a cell are classified as inorganic?
2. What substances in a cell are classified as organic?
3. What is the monomer of carbohydrates?
4. What structure do carbohydrates have?
5. What functions do carbohydrates perform?
6. What is the monomer of fats?
7. What structure do fats have?
8. What functions do fats perform?
9. What is a protein monomer? 10.What structure do proteins have? 11.What structures do proteins have?
12.What happens when a protein molecule denatures?
13.What functions do proteins perform?
14.What nucleic acids are known?
15.What is a monomer of nucleic acids?
16.What is included in the DNA nucleotide?
17.What is the structure of an RNA nucleotide?
18.What is the structure of a DNA molecule?
19.What functions does the DNA molecule perform?
20. What is the structure of rRNA?
21.What is the structure of mRNA?
22.What is the structure of tRNA?
23.What functions do ribonucleic acids perform?
24.What is the structure of ATP?
25.What functions does ATP perform in a cell?
Topic Keywords " Chemical composition cells"
nitrogenous base albumin
amino acid group
amphoteric compounds
anticodon
bacteria
squirrels
biological activity biological catalyst
biochemical reactions
disease
substances
species specificity
vitamins
water
hydrogen bonds secondary structure antibody production heat galactose hexoses hemoglobin heparin
hydrophobic compounds
glycogen
glycosides
glycoproteins
glycerol
globule
globulins
glucose
hormones
guanine
double helix deoxyribose denaturation disaccharide
dissociated state
DNA
unit of information living organism animal vital activity fatty acids adipose tissue fat-like substances fats
stock nutrients excess
individual specificity
energy source
drops
carboxyl group
quality acid
cell wall codon
temperature fluctuation
quantity
complementarity
final products
bones
starch
lactose
treatment
lipoproteins
macronutrients
macroergic connections
maltose
weight
cell membrane
microelements
mineral salts
myosin
mitochondria
molecule
milk sugar
monomer
monosaccharide
mucopolysaccharides
mucoproteins
hereditary information deficiency
inorganic substances nerve tissue nucleic acids nucleoproteins nucleotide metabolism metabolic processes organic substances pentoses
peptide bonds primary structure oxygen transfer fruits
subcutaneous tissue
polymer polysaccharide
semi-permeable membrane
order
a loss
water penetration
percent
radical
destruction
decay
solvent
plant
split
condensation reaction
renaturation
ribose
ribonuclease
ribosome
RNA
sugar
blood clotting
free state
bound state
seeds
heart
protein synthesis
layer
saliva
contractile proteins
structure
substrate
thermal conductivity
tetrose thymine
tissue specificity
tertiary structure
shamrock
trioses
triplet
cane sugar carbohydrates
ultramicroelements
uracil
plot
enzymes
fibrinogen
formula
phosphoric acid photosynthesis fructose function
chemical elements
chloroplasts
chromosome
cellulose
chain
cytosine
cytoplasm
quaternary structure ball
thyroid
elements
core