1. What types of energy do you know?

Answer. Exists large number types of energy. Here are some of them: Solar (electromagnetic), thermal, energy internal combustion, mechanical, hydraulic, gravitational, electromagnetic, nuclear, thermal, bioenergy.

2. Why is energy necessary for the life of any organism?

Answer. Energy is necessary for the synthesis of all specific substances of the body, maintaining its highly ordered organization, active transport of substances within cells, from one cell to another, from one part of the body to another, for the transmission of nerve impulses, the movement of organisms, maintaining a constant body temperature and for other purposes.

3. What vitamins do you know? What is their role?

Answer. Vitamins are a group of low molecular weight organic compounds that are relatively simple structure and diverse chemical nature. This is a chemically combined group of organic substances, united on the basis of their absolute necessity for heterotrophic organism as an integral part of food. Vitamins are found in food in very small quantities and are therefore classified as micronutrients.

Vitamins - (from the Latin vita - “life”) - substances that the body requires for normal functioning.

Vitamins participate in many biochemical reactions, performing a catalytic function in the composition active centers a large number of different enzymes or acting as information regulatory intermediaries, performing signaling functions of exogenous prohormones and hormones.

They are not a supplier of energy for the body and do not have significant plastic significance. However, vitamins play a vital role in metabolism.

Concentration of vitamins in tissues and daily requirement they are small, but with insufficient intake of vitamins into the body, characteristic and dangerous pathological changes occur.

Most vitamins are not synthesized in the human body. Therefore, they must be regularly and in sufficient quantities entering the body with food or in the form of vitamin-mineral complexes and food additives. The exception is vitamin K, a sufficient amount of which is normally synthesized in the human large intestine due to the activity of bacteria.

Three fundamental pathological conditions are associated with a violation of the supply of vitamins to the body: a lack of vitamin - hypovitaminosis, a lack of vitamin - avitaminosis, and an excess of vitamin - hypervitaminosis.

About one and a half dozen vitamins are known. Based on solubility, vitamins are divided into fat-soluble - A, D, E, F, K and water-soluble - all others. Fat-soluble vitamins accumulate in the body, and their depots are adipose tissue and the liver. Water-soluble vitamins are not stored in significant quantities, but are excreted in excess. This, on the one hand, explains the fact that hypovitaminosis of water-soluble vitamins is quite common, and on the other hand, hypervitaminosis of fat-soluble vitamins is sometimes observed.

Questions after §13

1. What is the structure of the ATP molecule?

Answer. Nucleotides are the structural basis for a number of organic substances important for life. The most widespread among them are high-energy compounds (high-energy compounds containing energy-rich, or high-energy, bonds), and among the latter is adenosine triphosphate (ATP).

ATP consists of the nitrogenous base adenine, the carbohydrate ribose, and (unlike DNA and RNA nucleotides) three phosphoric acid residues.

2. What function does ATP perform?

Answer. ATP is a universal store and carrier of energy in the cell. Almost all biochemical reactions occurring in the cell that require energy use ATP as its source. When one phosphoric acid residue is separated, ATP turns into adenosine diphosphate (ADP), if another phosphoric acid residue is separated (which is extremely rare), then ADP turns into adenosine monophosphate (AMP).

3. What connections are called macroergic?

Answer. When the third and second residues of phosphoric acid are separated, a large amount of energy is released (up to 40 kJ). This connection is called macroergic (it is denoted by the symbol ~). The bond between ribose and the first phosphoric acid residue is not high-energy, and its cleavage releases only about 14 kJ of energy.

ATP + H2O → ADP + H3PO4 + 40 kJ, ADP + H2O → AMP + H3PO4 + 40 kJ.

Macroergic compounds can also be formed on the basis of other nucleotides. For example, guanosine triphosphate (GTP) plays important role in a number of biochemical processes, but ATP is the most common and universal source of energy for most biochemical reactions occurring in the cell. ATP is found in the cytoplasm, mitochondria, plastids and nuclei.

4. What role do vitamins play in the body?

Answer. Biologically active organic compounds– vitamins (from the Latin vita – life) are absolutely necessary in small quantities for the normal functioning of organisms. They play an important role in exchange processes, often being integral part enzymes.

Vitamins are designated by Latin letters, although each of them also has a name. For example, vitamin C - ascorbic acid, vitamin A - retinol, etc. Some vitamins are soluble in fats, and they are called fat-soluble (A, D, E, K), others are soluble in water (C, B, PP, H) and accordingly are called water-soluble.

Both deficiency and excess of vitamins can lead to serious disorders in many physiological functions in the body.

Compare ATP to DNA and RNA. What are their similarities and differences?

Answer. Similarities: ATP, DNA and RNA are made up of nucleotides.

Differences: ATP-nucleotide, DNA and RNA polymers, ATP contains only one nitrogenous base - adenine, and DNA and RNA consist of four. ATP, unlike DNA and RNA, contains three phosphoric acid residues.

">Lecture No. 2

">Nucleic acids, ATP and other organic compounds of the cell

"> ">Types of nucleic acids">. There are two types of nucleic acids in cells: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). These biopolymers consist of monomers called nucleotides. DNA and RNA nucleotides are similar in basic structural features. Each nucleotide consists of three components, which connected by strong chemical bonds.

"> Each of the nucleotides that make up RNA contains a five-carbon sugar - ribose; one of 4 nitrogenous bases: adenine, guanine, cytosine, thymine (A, G, C, T); a phosphoric acid residue.

"> Nucleotides that make up DNA contain a five-carbon sugar deoxyribose; one of 4 nitrogenous bases: adenine, cytosine, guanine, thymine (A, G, C, T); a phosphoric acid residue.

"> As part of nucleotides, a ribose (or deoxyribose) molecule has a nitrogenous base attached on one side, and a phosphoric acid residue on the other. The nucleotides are connected to each other into long chains. The backbone of such a chain is formed by regularly alternating sugar and phosphoric acid residues, and the side groups this chain has 4 types of irregularly alternating nitrogenous bases.

"> A DNA molecule is a structure consisting of 2 strands, which are connected to each other along their entire length by hydrogen bonds.

"> Such a structure, characteristic only of DNA molecules, is called a double helix. A feature of the DNA structure is that opposite the nitrogenous base A in one chain lies the nitrogenous base T in the other chain, and opposite the nitrogenous base G is always the nitrogenous base C. Schematically, what has been said can be express as follows:

">A (adenine) T (thymine)

">T (thymine) A (adenine)

">G (guanine) C (cytosine)

">C (cytosine) G (guanine)

"> These base pairs are called complementary bases (complementary to each other). Strands of DNA in which the bases are located complementary to each other are called complementary strands.

"> The model of the structure of the DNA molecule was proposed by J. Watson and F. Crick in 1953. It was fully confirmed experimentally and played an important role in the development molecular biology and genetics. The order of nucleotides in DNA molecules determines the order of amino acids in linear protein molecules, i.e. their primary structure. A set of proteins determines the properties of a cell and an organism. DNA molecules store information about these properties and pass them on to generations of descendants, i.e. are carriers of hereditary information. DNA molecules are mainly found in the nuclei of cells and in small quantities in mitochondria and chloroplasts.

"> ">Main types of RNA">. Hereditary information stored in DNA molecules is realized through protein molecules. Information about the structure of the protein is transmitted to the cytoplasm by special RNA proteins, which are called informational RNA (mRNA). Information RNA is transferred to the cytoplasm, where protein synthesis occurs with the help of special organelles - ribosomes It is messenger RNA, which is built complementary to one of the DNA strands, that determines the order of amino acids in protein molecules.

"> Another type of RNA also takes part in protein synthesis - transport RNA (tRNA), which brings amino acids to the place of formation of protein molecules - ribosomes.

"> Each RNA molecule, unlike a DNA molecule, is represented by one strand; instead of deoxyribose, it contains ribose and instead of thymine, uracil.

">So, nucleic acids perform the most important functions in the cell biological functions. DNA stores hereditary information about all the properties of the cell and the organism as a whole. Various types RNAs take part in the implementation of hereditary information through protein synthesis.

">ATP">.

"> In any cell, in addition to proteins, fats, polysaccharides and nucleic acids, there are several thousand other organic compounds. They can be divided into final and intermediate products of biosynthesis and decay.

"> The end products of biosynthesis are organic compounds that play an independent role in the body or serve as monomers for the synthesis of biopolymers. The end products of biosynthesis include amino acids, from which proteins are synthesized in cells; nucleotides - monomers, from which nucleic acids (RNA and DNA) are synthesized ); glucose, which serves as a monomer for the synthesis of glycogen, starch, and cellulose.

"> ">Adenosine phosphoric acids">. A particularly important role in the bioenergetics of the cell is played by the adenyl nucleotide, to which 2 more phosphoric acid residues are attached. This substance is called adenosine triphosphoric acid (ATP). All cells use ATP energy for the processes of biosynthesis, movement, heat production, transmission of nerve impulses, luminescence , i.e. for all life processes.

"> Vitamins. K final products vitamins belong to biosynthesis. These include vital compounds that organisms of a given species are not able to synthesize themselves, but must receive ready-made from the outside. For example, vitamin C (ascorbic acid) is synthesized in the cells of most animals. The lack of a number of vitamins in the human and animal body leads to disruption of enzymes and is the cause of severe diseases - vitamin deficiencies.

Question 1. What is the structure of the ATP molecule?
ATP is adenosine triphosphate, a nucleotide belonging to the group of nucleic acids. The concentration of ATP in the cell is low (0.04%; in skeletal muscles 0.5%). The adenosine triphosphoric acid (ATP) molecule in its structure resembles one of the nucleotides of the RNA molecule. ATP includes three components: adenine, the five-carbon sugar ribose and three phosphoric acid residues, interconnected by special high-energy bonds.

Question 2. What is the function of ATP?
ATP is a universal source of energy for all reactions occurring in the cell. Energy is released when phosphoric acid residues are separated from the ATP molecule when high-energy bonds are broken. The bond between phosphoric acid residues is high-energy; upon its cleavage, it is released approximately 4 times more energy than when splitting other bonds. If one phosphoric acid residue is separated, then ATP turns into ADP (adenosine diphosphoric acid). This releases 40 kJ of energy. When the second phosphoric acid residue is separated, another 40 kJ of energy is released, and ADP is converted into AMP (adenosine monophosphate). The released energy is used by the cell. The cell uses ATP energy in biosynthesis processes, during movement, during heat production, during nerve impulses, during photosynthesis, etc. ATP is a universal energy accumulator in living organisms.
During the hydrolysis of a phosphoric acid residue, energy is released:
ATP + H 2 O = ADP + H 3 PO 4 + 40 kJ/mol

Question 3. What connections are called macroergic?
The bonds between phosphoric acid residues are called macroergic, since their rupture releases a large amount of energy (four times more than the cleavage of other chemical bonds).

Question 4. What role do vitamins play in the body?
Metabolism is impossible without the participation of vitamins. Vitamins are low-molecular organic substances vital for the existence of the human body. Vitamins are either not produced at all in human body, or are produced in insufficient quantities. Since vitamins are most often the non-protein part of enzyme molecules (coenzymes) and determine the intensity of many physiological processes in the human body, their constant intake into the body is necessary. Exceptions to some extent are vitamins B and A, which can accumulate in small quantities in the liver. In addition, some vitamins (B 1 B 2, K, E) are synthesized by bacteria living in the large intestine, from where they are absorbed into the human blood. In case of a lack of vitamins in food or illness gastrointestinal tract the supply of vitamins in the blood decreases, and diseases commonly called hypovitaminosis occur. In the complete absence of any vitamin, more severe disorder, called vitamin deficiency. For example, vitamin D regulates the exchange of calcium and phosphorus in the human body, vitamin K is involved in the synthesis of prothrombin and promotes normal blood clotting.
Vitamins are divided into water-soluble (C, PP, B vitamins) and fat-soluble (A, D, E, etc.). Water-soluble vitamins are absorbed in an aqueous solution, and when they are in excess in the body, they are easily excreted in the urine. Fat-soluble vitamins are absorbed along with fats, so impaired digestion and absorption of fats is accompanied by a lack of vitamins (A, O, K). A significant increase in the content of fat-soluble vitamins in food can cause a number of metabolic disorders, since these vitamins are poorly excreted from the body. Currently, there are at least two dozen substances related to vitamins.

Question 1. What is the structure of the ATP molecule?
ATP is adenosine triphosphate, a nucleotide belonging to the group of nucleic acids. The concentration of ATP in the cell is low (0.04%; in skeletal muscles 0.5%). The adenosine triphosphoric acid (ATP) molecule in its structure resembles one of the nucleotides of the RNA molecule. ATP includes three components: adenine, the five-carbon sugar ribose and three phosphoric acid residues, interconnected by special high-energy bonds.

Question 2. What is the function of ATP?
ATP is a universal source of energy for all reactions occurring in the cell. Energy is released when phosphoric acid residues are separated from the ATP molecule when high-energy bonds are broken. The bond between phosphoric acid residues is high-energy; its cleavage releases approximately 4 times more energy than the cleavage of other bonds. If one phosphoric acid residue is separated, then ATP turns into ADP (adenosine diphosphoric acid). This releases 40 kJ of energy. When the second phosphoric acid residue is separated, another 40 kJ of energy is released, and ADP is converted into AMP (adenosine monophosphate). The released energy is used by the cell. The cell uses ATP energy in biosynthesis processes, during movement, during heat production, during nerve impulses, during photosynthesis, etc. ATP is a universal energy accumulator in living organisms.
During the hydrolysis of a phosphoric acid residue, energy is released:
ATP + H 2 O = ADP + H 3 PO 4 + 40 kJ/mol

Question 3. What connections are called macroergic?
The bonds between phosphoric acid residues are called macroergic, since their rupture releases a large amount of energy (four times more than the cleavage of other chemical bonds).

Question 4. What role do vitamins play in the body?
Metabolism is impossible without the participation of vitamins. Vitamins are low-molecular organic substances vital for the existence of the human body. Vitamins are either not produced at all in the human body, or are produced in insufficient quantities. Since vitamins are most often the non-protein part of enzyme molecules (coenzymes) and determine the intensity of many physiological processes in the human body, their constant intake into the body is necessary. Exceptions to some extent are vitamins B and A, which can accumulate in small quantities in the liver. In addition, some vitamins (B 1 B 2, K, E) are synthesized by bacteria living in the large intestine, from where they are absorbed into the human blood. If there is a lack of vitamins in food or diseases of the gastrointestinal tract, the supply of vitamins in the blood decreases, and diseases generally called hypovitaminosis occur. In the complete absence of any vitamin, a more severe disorder occurs, called vitamin deficiency. For example, vitamin D regulates the exchange of calcium and phosphorus in the human body, vitamin K is involved in the synthesis of prothrombin and promotes normal blood clotting.
Vitamins are divided into water-soluble (C, PP, B vitamins) and fat-soluble (A, D, E, etc.). Water-soluble vitamins are absorbed in an aqueous solution, and when they are in excess in the body, they are easily excreted in the urine. Fat-soluble vitamins are absorbed along with fats, so impaired digestion and absorption of fats is accompanied by a lack of vitamins (A, O, K). A significant increase in the content of fat-soluble vitamins in food can cause a number of metabolic disorders, since these vitamins are poorly excreted from the body. Currently, there are at least two dozen substances related to vitamins.