What is the monomer of complex carbohydrates. Carbohydrates. Glucose is

Main types of biopolymers

Carbohydrates

• Carbohydrate monomers are simple sugars or monosaccharides. Most often it is glucose and fructose. The most important function of monosaccharides is to provide the body with energy. In living cells, simple sugars are broken down into carbon dioxide and water, which is accompanied by the release of energy. Cells use this energy for their various needs.

• Glucose- this is the basic form that is stored in the human body as a store of energy in the form of glycogen in the muscles and liver. In nature, glucose is found in sweet fruits and vegetables: grapes, berries, oranges, carrots, corn. Glucose is also produced on an industrial scale. An example is corn syrup.

• Fructose found in honey, ripe sweet fruits and vegetables. Before metabolizing glucose, the body must first convert fructose into glucose.

The structure of the glucose molecule Linear form of glucose: CHOCH(OH)CH(OH)CH(OH)CH(OH)CH2(OH)

• Glucose predominantly exists in a cyclic form. The a- and b-forms of cyclic glucose are known, differing in the orientation of the hydroxyl at C-1:

Simple sugars can combine with each other to form disaccharides

• sucrose- table sugar obtained from sugar beets, cane, as well as brown sugar, molasses. It is found in small amounts in fruits and vegetables.

• Lactose- milk sugar, the only carbohydrate of animal origin, therefore it is very important in human nutrition. The content of lactose in milk depends on the type of milk and varies from 2 to 8%.

• Maltose- malt sugar, formed during the formation of malt and fermentation of grapes. Present in beer, muesli and baby food enriched with maltose.

Lipids

• Lipids are diverse in structure and in the ratio of their constituent elements. However, they all have a common property - they are all non-polar. They are soluble in chloroform and ethers, but practically insoluble in water. Due to this property, lipids are the most important components of membranes.

• Lipids - the main form of energy storage in the animal body, are stored in a concentrated form (without water). Any excess sugar not consumed immediately quickly turns into fat. There are three groups of lipids:

• Triglycerols (or triglycerides) - These are molecules formed as a result of the addition of three fatty acid residues to one molecule of the trihydric alcohol glycerol.

• This group includes fats and oils. Fats remain solid at room temperature, while oils remain liquid. Oils contain more unsaturated fatty acids.

• Phospholipids- are similar to triglycerols, but in them one or two fatty acid residues are replaced by groups containing phosphorus. Phospholipids are essential components of biological membranes.

Steroids - These are lipids, which are based on the basis of four rings. In various steroids, side groups are attached to this basic skeleton. Steroids include a number of hormones (sex hormones, cortisone). The steroid cholesterol is an important component of cell membranes in animals, but its excess in the body can lead to the formation of gallstones and to diseases of the cardiovascular system.

• The structure of the cholesterol molecule

Squirrels

• Proteins are composed of carbon, oxygen, hydrogen and nitrogen. Some proteins also contain sulfur. The role of monomers in proteins is played by amino acids.

• Each amino acid has a carboxyl group (-COOH) and an amino group (-NH2).

• There are 20 common types of amino acids found in proteins.

• The functions of proteins are enzymatic, building (membranes), energy, motor, protective and regulatory.

Proteins have four structures:

• Primary - polypeptide, a long chain containing from 100 to 300 amino acids, is formed by peptide bonds.

• Secondary - formed as a result of the formation of hydrogen bonds between adjacent peptide bonds. During the formation of the secondary structure, the protein molecule is packed either in a left-handed helix or in a beta configuration, which is characteristic of proteins that perform a building function.

• Tertiary is formed as a result of the formation of 4 types of bonds: hydrogen, ionic interactions, the formation of disulfide bridges and hydrophilic-hydrophobic bonds (Van Der Val).

• There are globular and fibrillar tertiary structures. The tertiary structure for most proteins is working, because. it is energetically more beneficial.

• Some proteins form a quaternary structure - it is a complex of proteins and other organic substances. The shaping forces are the same as those of the tertiary structure.

Protein denaturation

• This is the loss of the biological activity of proteins when weak bonds are broken, the destruction of the native (natural) protein structure under the action of denaturing agents: high temperature, ultraviolet radiation, acids, alkalis, heavy metal ions. Denaturation can be reversible (renaturation) and irreversible.

Carbohydrates- organic compounds, the composition of which in most cases is expressed by the general formula C n(H2O) m (n and m≥ 4). Carbohydrates are divided into monosaccharides, oligosaccharides and polysaccharides.

Monosaccharides- simple carbohydrates, depending on the number of carbon atoms, are divided into trioses (3), tetroses (4), pentoses (5), hexoses (6) and heptoses (7 atoms). The most common are pentoses and hexoses. Properties of monosaccharides- easily soluble in water, crystallize, have a sweet taste, can be presented in the form of α- or β-isomers.

Ribose and deoxyribose belong to the group of pentoses, are part of the RNA and DNA nucleotides, ribonucleoside triphosphates and deoxyribonucleoside triphosphates, etc. Deoxyribose (C 5 H 10 O 4) differs from ribose (C 5 H 10 O 5) in that it has a hydrogen atom at the second carbon atom, not a hydroxyl group like ribose.

Glucose or grape sugar(C 6 H 12 O 6), belongs to the group of hexoses, can exist in the form of α-glucose or β-glucose. The difference between these spatial isomers is that at the first carbon atom in α-glucose the hydroxyl group is located under the plane of the ring, while in β-glucose it is above the plane.

Glucose is:

1. one of the most common monosaccharides,
2. the most important source of energy for all types of work occurring in the cell (this energy is released during the oxidation of glucose during respiration),
3. monomer of many oligosaccharides and polysaccharides,
4. an essential component of blood.

Fructose or fruit sugar, belongs to the group of hexoses, sweeter than glucose, found in free form in honey (more than 50%) and fruits. It is a monomer of many oligosaccharides and polysaccharides.

Oligosaccharides- carbohydrates formed as a result of a condensation reaction between several (from two to ten) monosaccharide molecules. Depending on the number of monosaccharide residues, disaccharides, trisaccharides, etc. are distinguished. Disaccharides are the most common. Properties of oligosaccharides- dissolve in water, crystallize, the sweet taste decreases as the number of monosaccharide residues increases. The bond formed between two monosaccharides is called glycosidic.

Sucrose or cane or beet sugar, is a disaccharide consisting of glucose and fructose residues. Found in plant tissues. It is a food product (common name - sugar). In industry, sucrose is produced from sugar cane (stems contain 10-18%) or sugar beets (root crops contain up to 20% sucrose).

Maltose or malt sugar, is a disaccharide consisting of two glucose residues. Present in germinating seeds of cereals.

Lactose or milk sugar, is a disaccharide consisting of glucose and galactose residues. Present in the milk of all mammals (2-8.5%).

Polysaccharides- these are carbohydrates formed as a result of the polycondensation reaction of a multitude (several tens or more) of monosaccharide molecules. Properties of polysaccharides- do not dissolve or dissolve poorly in water, do not form clearly formed crystals, do not have a sweet taste.

Starch(C 6 H 10 O 5) n is a polymer whose monomer is α-glucose. Starch polymer chains contain branched (amylopectin, 1,6-glycosidic bonds) and unbranched (amylose, 1,4-glycosidic bonds) sections. Starch is the main reserve carbohydrate of plants, is one of the products of photosynthesis, accumulates in seeds, tubers, rhizomes, bulbs. The starch content in rice grains is up to 86%, wheat - up to 75%, corn - up to 72%, in potato tubers - up to 25%. Starch is the main carbohydrate human food (digestive enzyme - amylase).

Glycogen(C 6 H 10 O 5) n- a polymer, the monomer of which is also α-glucose. The polymeric chains of glycogen resemble the amylopectin sections of starch, but unlike them, they branch even more strongly. Glycogen is the main reserve carbohydrate of animals, in particular humans. Accumulates in the liver (content - up to 20%) and muscles (up to 4%), is a source of glucose.

(C 6 H 10 O 5) n is a polymer whose monomer is β-glucose. Cellulose polymer chains do not branch (β-1,4-glycosidic bonds). The main structural polysaccharide of plant cell walls. The cellulose content in wood is up to 50%, in the fibers of cotton seeds - up to 98%. Cellulose is not broken down by human digestive juices, because. it lacks the enzyme cellulase, which breaks bonds between β-glucoses.

Inulin is a polymer whose monomer is fructose. Reserve carbohydrate of plants of the Compositae family.

Glycolipids- complex substances formed as a result of the combination of carbohydrates and lipids.

Glycoproteins- complex substances formed as a result of the combination of carbohydrates and proteins.

Functions of carbohydrates

The structure and function of lipids

Lipids do not have a single chemical characteristic. In most benefits, giving lipid determination, they say that this is a combined group of water-insoluble organic compounds that can be extracted from the cell with organic solvents - ether, chloroform and benzene. Lipids can be divided into simple and complex.

Simple lipids in the majority are esters of higher fatty acids and trihydric alcohol glycerol - triglycerides. Fatty acid have: 1) the same grouping for all acids - a carboxyl group (-COOH) and 2) a radical by which they differ from each other. The radical is a chain of various numbers (from 14 to 22) groups -CH 2 -. Sometimes the fatty acid radical contains one or more double bonds (-CH=CH-), such fatty acid is called unsaturated. If a fatty acid has no double bonds, it is called rich. In the formation of triglyceride, each of the three hydroxyl groups of glycerol undergoes a condensation reaction with a fatty acid to form three ester bonds.

If triglycerides are dominated by saturated fatty acids, then at 20°C they are solid; they are called fats, they are characteristic of animal cells. If triglycerides are dominated by unsaturated fatty acids, then at 20 °C they are liquid; they are called oils, they are characteristic of plant cells.

1 - triglyceride; 2 - ester bond; 3 - unsaturated fatty acid;
4 - hydrophilic head; 5 - hydrophobic tail.

The density of triglycerides is lower than that of water, so they float in water, are on its surface.

Simple lipids also include waxes- esters of higher fatty acids and macromolecular alcohols (usually with an even number of carbon atoms).

Complex lipids. These include phospholipids, glycolipids, lipoproteins, etc.

Phospholipids- triglycerides in which one fatty acid residue is replaced by a phosphoric acid residue. They take part in the formation of cell membranes.

Glycolipids- see above.

Lipoproteins- complex substances formed as a result of the combination of lipids and proteins.

Lipoids- fat-like substances. These include carotenoids (photosynthetic pigments), steroid hormones (sex hormones, mineralocorticoids, glucocorticoids), gibberellins (plant growth substances), fat-soluble vitamins (A, D, E, K), cholesterol, camphor, etc.

Functions of lipids

Go to lectures №1"Introduction. Chemical elements of the cell. Water and other inorganic compounds"

Go to lectures №3“The structure and function of proteins. Enzymes»

Simple organic molecules often serve as raw materials for the synthesis of larger macromolecules. macromolecule is a giant molecule built from many repeating units.

Molecules built in this way are called polymers, and the units of which they are composed are called monomers. In the process of connecting the individual links to each other (with the so-called condensation), water is removed.

The opposite process polymer degradation- carried out by hydrolysis, i.e. by adding water. There are three main types of macromolecules in living organisms: polysaccharides, proteins, and nucleic acids. The monomers for them, respectively, are monosaccharides and nucleotides.

macromolecules make up about 90% of the dry mass of cells. Polysaccharides play the role of reserve nutrients and perform structural functions, while proteins and nucleic acids can be considered as " information molecules».
Macromolecules exist not only in living nature, but also in inanimate nature, in particular, many equipment based on macromolecules are created by man himself.

This means that in proteins and nucleic acids the sequence is important monomer units and in them it varies much more than in polysaccharides, the composition of which is usually limited to one or two different types of subunits. The reasons for this will become clear to us later. In the same chapter, we will consider in detail all three classes of macromolecules and their subunits. To this consideration, we will add lipids - molecules, as a rule, much smaller, but also built from simple organic molecules.

Carbohydrates

carbohydrates call substances consisting of carbon, hydrogen and, with the general formula C x (H 2 O) y where x: and y can have different values. The name "carbohydrates" reflects the fact that hydrogen and oxygen are present in the molecules of these substances in the same ratio as in a water molecule (two hydrogen atoms for each oxygen atom). All carbohydrates are either aldehydes or ketones and there are always several hydroxyl groups in their molecules. The chemical properties of carbohydrates are determined precisely by these groups - aldehyde, hydroxyl and keto groups. Aldehydes, for example, are easily oxidized and therefore are powerful reducing agents. The structure of these groups is presented in the table.

Carbohydrates divided into three main classes: monosaccharides, disaccharides and polysaccharides.

1. Give definitions of concepts.
Carbohydrates- organic substances containing a carbonyl group and several hydroxyl groups.
Monosaccharide - a simple carbohydrate that does not break down into simpler compounds during hydrolysis.
disaccharide- a carbohydrate, which is a compound of two monosaccharides.

2. Complete the scheme "Diversity of carbohydrates in the cell."

3. Consider figure 11 of the textbook and give examples of monosaccharides, which include:
five carbon atoms: ribose, deoxyribose;
six carbon atoms: glucose, fructose.

4. Fill in the table.

Biological functions of mono- and disaccharides

5. Name water-soluble carbohydrates. What features of the structure of their molecules provide the property of solubility?
Monosaccharides (glucose, fructose) and disaccharides (sucrose). Their molecules are small and polar, therefore soluble in water. Polysaccharides form long chains that do not dissolve in water

6. Fill in the table.

BIOLOGICAL FUNCTIONS OF POLYSACCHARIDES

7. The polysaccharide chitin is part of the structure of the cell walls of fungi and forms the basis of the external skeleton of arthropods. Which of the known polysaccharides does it show functional similarity with? Justify the answer.
Chitin is a substance very similar in structure, physicochemical properties and biological role to cellulose. It performs protective and supporting functions, is contained in the cell walls of fungi, some algae, bacteria.

8. Give definitions of concepts.
Polypeptide- a chemical substance consisting of a long chain of amino acids linked by peptide bonds.
Denaturation - loss by proteins or nucleic acids of their natural properties due to a violation of the spatial structure of their molecules.
Renaturation - restoration (after denaturation) of the biologically active spatial structure of the biopolymer (protein or nucleic acid).

9. Explain the statement: "Proteins are carriers and organizers of life."
According to Engels, “Wherever we meet life, it is associated with some protein body, and wherever we meet any protein body that is not in the process of decomposition, we, without exception, meet the phenomena of life ...”. "Life is a way of existence of protein bodies...".

10. Write the general structural formula of an amino acid. Explain why a protein monomer is called that.
RCH(NH2)COOH. Amino acids combine the properties of acids and amines, that is, they contain, along with the carboxyl group -COOH, the amino group -NH2.

11. How do different amino acids differ from each other?
Amino acids differ from each other in the structure of the radical.

12. Fill in the cluster "Diversity of proteins and their functions".
Proteins: hormones, transport proteins, enzymes, toxins, antibiotics, storage proteins, protective proteins, motor proteins, structural proteins.

13. Finish filling in the table.

14. Using a textbook, explain the essence of the statement: "Biochemical reactions occurring in the presence of enzymes are the basis of cell vital activity."
Enzyme proteins catalyze many reactions, ensure the coherence of the cell ensemble of living organisms, accelerating the rate of chemical reactions many times over.

15. Give examples of proteins involved in the listed processes.
Running, walking, jumping - actin and myosin.
Growth is somatotropin.
The transport of oxygen and carbon dioxide in the blood is hemoglobin.
The growth of nails and hair is keratin.
Blood clotting - prothrombin, fibrinogen.
Oxygen binding in muscles - myoglobin.

16. Establish a correspondence between specific proteins and their functions.
1. Prothrombin
2. Collagen
3. Actin
4. Somatotropin
5. Hemoglobin
6. Insulin
Role in the body
A. Muscle contractile protein
B. Pituitary hormone
B. Provides blood clotting
G. Included in connective tissue fibers
D. Pancreatic hormone
E. Carries oxygen

17. What is the disinfectant property of ethyl alcohol based on?
It destroys proteins (including toxins) of bacteria, leads to their denaturation.

18. Why does a boiled egg immersed in cold water not return to its original state?
Irreversible denaturation of chicken egg protein occurs under the influence of high temperature.

19. When oxidizing 1 g of proteins, the same amount of energy is released as when oxidizing 1 g of carbohydrates. Why does the body use proteins as a source of energy only in extreme cases?
The functions of proteins are, firstly, building, enzymatic, transport functions, and only in extreme cases the body uses or spends proteins for energy, only when carbohydrates and fats do not enter the body, when the body is starving.

20. Choose the correct answer.
Test 1
Proteins that increase the rate of chemical reactions in the cell:
2) enzymes;
Test 2
The monomer of complex carbohydrates is:
4) glucose.
Test 3
Carbohydrates in the cell do not perform the function:
3) storage of hereditary information.
Test 4
A polymer whose monomers are arranged in a single line:
2) unbranched polymer;
Test 5
Amino acids do not include:
3) phosphorus;
Test 6
Animals have glycogen, while plants have:
3) starch;
Test 7
Hemoglobin has, but lysozyme does not:
4) quaternary structure.

21. Explain the origin and general meaning of the word (term), based on the meaning of the roots that make it up.

22. Choose a term and explain how its modern meaning corresponds to the original meaning of its roots.
Chosen term: deoxyribose.
Match: The term matches the meaning. This deoxysugar is a derivative of ribose, where the hydroxyl group at the second carbon atom is replaced by hydrogen with the loss of an oxygen atom (deoxy is the absence of an oxygen atom).

23. Formulate and write down the main ideas of § 2.5.
Carbohydrates and proteins are organic substances of the cell. Carbohydrates include: monosaccharides (ribose, deoxyribose, glucose), disaccharides (sucrose), polysaccharides (starch, glycogen, cellulose, chitin). In the body, they perform the following functions: energy, storage, structural.
Proteins whose monomers are amino acids have primary, secondary, tertiary, and often quaternary structures. They perform important functions in the body: they are hormones, enzymes, toxins, antibiotics, reserve, protective, transport, motor and structural proteins.

All carbohydrates are made up of individual "units", which are saccharides. By ability tohydrolysison themonomerscarbohydrates are dividedinto two groups: simple and complex. Carbohydrates containing one unit are calledmonosaccharides, two units -disaccharides, two to ten unitsoligosaccharides, and more than tenpolysaccharides.

Monosaccharides quickly increase blood sugar, and have a high glycemic index, so they are also called fast carbohydrates. They dissolve easily in water and are synthesized in green plants.

Carbohydrates consisting of 3 or more units are calledcomplex. Foods rich in complex carbohydrates gradually increase their glucose content and have a low glycemic index, which is why they are also called slow carbohydrates. Complex carbohydrates are products of polycondensation of simple sugars (monosaccharides) and, unlike simple ones, in the process of hydrolytic cleavage they are able to decompose into monomers, with the formation of hundreds and thousandsmoleculesmonosaccharides.

Stereoisomerism of monosaccharides: isomerglyceraldehydein which, when the model is projected onto the plane, the OH group at the asymmetric carbon atom is located on the right side, it is considered to be D-glyceraldehyde, and the mirror image is L-glyceraldehyde. All isomers of monosaccharides are divided into D- and L-forms according to the similarity of the location of the OH group at the last asymmetric carbon atom near CH 2 OH groups (ketoses contain one asymmetric carbon atom less than aldoses with the same number of carbon atoms). Naturalhexoses – glucose, fructose, mannoseandgalactose- According to stereochemical configurations, they are classified as D-series compounds.

Polysaccharides - the general name of the class of complex high-molecular carbohydrates,moleculesconsisting of tens, hundreds or thousandsmonomers – monosaccharides. From the point of view of the general principles of structure in the group of polysaccharides, it is possible to distinguish between homopolysaccharides synthesized from the same type of monosaccharide units and heteropolysaccharides, which are characterized by the presence of two or more types of monomeric residues.

https :// en . wikipedia . org / wiki /Carbohydrates

1.6. Lipids - nomenclature and structure. Lipid polymorphism.

Lipids - an extensive group of natural organic compounds, including fats and fat-like substances. Simple lipid molecules are composed of alcohol andfatty acids, complex - from alcohol, high molecular weight fatty acids and other components.

Lipid classification

Simple lipids are lipids that include carbon (C), hydrogen (H) and oxygen (O) in their structure.

Complex lipids - These are lipids that include in their structure, in addition to carbon (C), hydrogen (H) and oxygen (O), and other chemical elements. Most often: phosphorus (P), sulfur (S), nitrogen (N).

https:// en. wikipedia. org/ wiki/Lipids

Literature:

1) Cherkasova L. S., Merezhinsky M. F., Metabolism of fats and lipids, Minsk, 1961;

2) Markman A. L., Chemistry of lipids, v. 12, Tash., 1963 - 70;

3) Tyutyunnikov B. N., Chemistry of fats, M., 1966;

4) Mahler G., Kordes K., Fundamentals of biological chemistry, trans. from English, M., 1970.

1.7. biological membranes. Forms of lipid aggregation. The concept of the liquid-crystal state. Lateral diffusion and flip flops.

membranes delimit the cytoplasm from the environment, and also form the membranes of the nuclei, mitochondria and plastids. They form a labyrinth of the endoplasmic reticulum and flattened stacked vesicles that make up the Golgi complex. The membranes form lysosomes, large and small vacuoles of plant and fungal cells, pulsating vacuoles of protozoa. All these structures are compartments (compartments) designed for certain specialized processes and cycles. Therefore, without membranes, the existence of a cell is impossible.

Diagram of the structure of the membrane: a – three-dimensional model; b - planar image;

1 - proteins adjacent to the lipid layer (A), immersed in it (B) or penetrating it through (C); 2 - layers of lipid molecules; 3 - glycoproteins; 4 - glycolipids; 5 - hydrophilic channel functioning as a pore.

The functions of biological membranes are as follows:

1) Delimit the contents of the cell from the external environment and the contents of the organelles from the cytoplasm.

2) Provide transport of substances into and out of the cell, from the cytoplasm to the organelles and vice versa.

3) They act as receptors (receiving and converting signals from the environment, recognition of cell substances, etc.).

4) They are catalysts (ensuring near-membrane chemical processes).

5) Participate in the transformation of energy.

http:// sbio. info/ page. php? id=15

Lateral diffusion is the chaotic thermal movement of lipid and protein molecules in the plane of the membrane. During lateral diffusion, adjacent lipid molecules jump around, and as a result of such successive jumps from one place to another, the molecule moves along the membrane surface.

The movement of molecules along the surface of the cell membrane during time t was determined experimentally by the method of fluorescent labels - fluorescent molecular groups. Fluorescent labels make fluorescent molecules, the movement of which on the cell surface can be studied, for example, by examining under a microscope the spreading rate of the fluorescent spot created by such molecules on the cell surface.

flip flop is the diffusion of membrane phospholipid molecules across the membrane.

The rate of jumps of molecules from one surface of the membrane to another (flip-flop) was determined by the spin label method in experiments on model lipid membranes - liposomes.

Some of the phospholipid molecules from which liposomes were formed were labeled with spin labels attached to them. Liposomes were exposed to ascorbic acid, as a result of which unpaired electrons on the molecules disappeared: paramagnetic molecules became diamagnetic, which could be detected by a decrease in the area under the curve of the EPR spectrum.

Thus, jumps of molecules from one surface of a bilayer to another (flip-flop) occur much more slowly than jumps during lateral diffusion. The average time for a phospholipid molecule to flip-flop (T ~ 1 hour) is tens of billions of times longer than the average time for a molecule to jump from one place to another in the membrane plane.

The concept of the liquid-crystal state

The solid body can becrystalline , andamorphous. In the first case, there is a long-range order in the arrangement of particles at distances much greater than intermolecular distances (crystal lattice). In the second, there is no long-range order in the arrangement of atoms and molecules.

The difference between an amorphous body and a liquid is not in the presence or absence of long-range order, but in the nature of particle motion. The molecules of a liquid and a solid make oscillatory (sometimes rotational) motions around the equilibrium position. After some average time (“time of settled life”), the molecules jump to another equilibrium position. The difference is that the "settled time" in a liquid is much shorter than in a solid state.

Lipid bilayer membranes are liquid under physiological conditions, the “settled life time” of a phospholipid molecule in the membrane is 10 −7 – 10 −8 with.

Molecules in the membrane are not randomly arranged; long-range order is observed in their arrangement. Phospholipid molecules are in a double layer, and their hydrophobic tails are approximately parallel to each other. There is also order in the orientation of the polar hydrophilic heads.

The physiological state in which there is a long-range order in the mutual orientation and arrangement of molecules, but the state of aggregation is liquid, is calledliquid crystal state. Liquid crystals can form not in all substances, but in substances from "long molecules" (the transverse dimensions of which are smaller than the longitudinal ones). There may be various liquid crystal structures: nematic (filamentous), when long molecules are oriented parallel to each other; smectic - molecules are parallel to each other and arranged in layers; cholestic - the molecules are parallel to each other in the same plane, but in different planes the orientations of the molecules are different.

http:// www. studfiles. en/ preview/1350293/

Literature: ON THE. Lemeza, L.V. Kamlyuk, N.D. Lisov. "Biology manual for applicants to universities."

1.8. Nucleic acids. Heterocyclic bases, nucleosides, nucleotides, nomenclature. Spatial structure of nucleic acids - DNA, RNA (tRNA, rRNA, mRNA). Ribosomes and the cell nucleus. Methods for determining the primary and secondary structure of nucleic acids (sequencing, hybridization).

Nucleic acids - phosphorus-containing biopolymers of living organisms that provide storage and transmission of hereditary information.

Nucleic acids are biopolymers. Their macromolecules consist of repeatedly repeating units, which are represented by nucleotides. And they are logically namedpolynucleotides. One of the main characteristics of nucleic acids is their nucleotide composition. The composition of a nucleotide (a structural unit of nucleic acids) includesthree components:

– nitrogenous base. May be pyrimidine or purine. Nucleic acids contain 4 different types of bases: two of them belong to the class of purines and two belong to the class of pyrimidines.

– rest of phosphoric acid.

– Monosaccharide - ribose or 2-deoxyribose. Sugar, which is part of the nucleotide, contains five carbon atoms, i.e. is a pentose. Depending on the type of pentose present in the nucleotide, two types of nucleic acids are distinguished- ribonucleic acids (RNA), which contain ribose, anddeoxyribonucleic acids (DNA), containing deoxyribose.

Nucleotide at its core, it is the phosphate ester of the nucleoside.The composition of the nucleoside There are two components: a monosaccharide (ribose or deoxyribose) and a nitrogenous base.

http :// sbio . info / page . php ? id =11

Nitrogenous bases – heterocyclicorganic compounds, derivativespyrimidineandpurine, included innucleic acids. For the abbreviated designation, capital Latin letters are used. The nitrogenous bases areadenine(A)guanine(G)cytosine(C) which are part of both DNA and RNA.Timin(T) is only part of DNA, anduracil(U) occurs only in RNA.