The most important substance in the cells of living organisms is adenosine triphosphate or adenosine triphosphate. If we enter the abbreviation of this name, we get ATP. This substance belongs to the group of nucleoside triphosphates and plays a leading role in metabolic processes in living cells, being an irreplaceable source of energy for them.
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The discoverers of ATP were biochemists from the Harvard School of Tropical Medicine - Yellapragada Subbarao, Karl Lohman and Cyrus Fiske. The discovery occurred in 1929 and became a major milestone in the biology of living systems. Later, in 1941, German biochemist Fritz Lipmann discovered that ATP in cells is the main carrier of energy.
ATP structure
This molecule has a systematic name, which is written as follows: 9-β-D-ribofuranosyladenine-5′-triphosphate, or 9-β-D-ribofuranosyl-6-amino-purine-5′-triphosphate. What compounds make up ATP? Chemically, it is adenosine triphosphate ester - derivative of adenine and ribose. This substance is formed by combining adenine, which is a purine nitrogenous base, with the 1′-carbon of ribose using a β-N-glycosidic bond. α-, β-, and γ-phosphoric acid molecules are then sequentially added to the 5′-carbon of ribose.
Thus, the ATP molecule contains compounds such as adenine, ribose and three phosphoric acid residues. ATP is a special compound containing bonds that release large amounts of energy. Such bonds and substances are called high-energy. During the hydrolysis of these bonds of the ATP molecule, an amount of energy is released from 40 to 60 kJ/mol, and this process is accompanied by the elimination of one or two phosphoric acid residues.
This is how these chemical reactions are written:
- 1). ATP + water → ADP + phosphoric acid + energy;
- 2). ADP + water →AMP + phosphoric acid + energy.
The energy released during these reactions is used in further biochemical processes that require certain energy inputs.
The role of ATP in a living organism. Its functions
What function does ATP perform? First of all, energy. As mentioned above, the main role of adenosine triphosphate is to provide energy for biochemical processes in a living organism. This role is due to the fact that, due to the presence of two high-energy bonds, ATP acts as a source of energy for many physiological and biochemical processes that require large energy inputs. Such processes are all reactions of the synthesis of complex substances in the body. This is, first of all, the active transfer of molecules through cell membranes, including participation in the creation of intermembrane electrical potential, and the implementation of muscle contraction.
In addition to the above, we list a few more: no less important functions of ATP, such as:
How is ATP formed in the body?
The synthesis of adenosine triphosphoric acid is ongoing, because the body always needs energy for normal functioning. At any given moment, there is very little of this substance - approximately 250 grams, which is an “emergency reserve” for a “rainy day.” During illness, there is intense synthesis of this acid, because a lot of energy is required for the functioning of the immune and excretory systems, as well as the body’s thermoregulation system, which is necessary for effective fight with the onset of illness.
In what ATP cells most? These are cells of muscle and nervous tissue, since energy exchange processes occur most intensively in them. And this is obvious, because muscles participate in movement that requires contraction of muscle fibers, and neurons transmit electrical impulses, without which the functioning of all body systems is impossible. Therefore, it is so important for the cell to maintain unchanged and high level adenosine triphosphate.
How can adenosine triphosphate molecules be formed in the body? They are formed by the so-called phosphorylation of ADP (adenosine diphosphate). This chemical reaction as follows:
ADP + phosphoric acid + energy → ATP + water.
Phosphorylation of ADP occurs with the participation of catalysts such as enzymes and light, and is carried out in one of three ways:
Both oxidative and substrate phosphorylation uses the energy of substances that are oxidized during such synthesis.
Conclusion
Adenosine triphosphoric acid- This is the most frequently renewed substance in the body. How long does an adenosine triphosphate molecule live on average? In the human body, for example, its lifespan is less than one minute, so one molecule of such a substance is born and decays up to 3000 times per day. Amazingly, during the day human body synthesizes about 40 kg of this substance! The need for this “internal energy” is so great for us!
The entire cycle of synthesis and further use of ATP as energy fuel for metabolic processes in the body of a living being represents the very essence of energy metabolism in this organism. Thus, adenosine triphosphate is a kind of “battery” that ensures the normal functioning of all cells of a living organism.
What makes a person move? What is energy metabolism? Where does the body's energy come from? How long will it last? At what physical activity, what energy is consumed? As you can see, there are a lot of questions. But most of them appear when you start studying this topic. I will try to make life easier for the most curious and save time. Go…
Energy metabolism is a set of reactions of the breakdown of organic substances, accompanied by the release of energy.
To ensure movement (actin and myosin filaments in the muscle), the muscle requires Adenosine TriPhosphate (ATP). When chemical bonds between phosphates are broken, energy is released, which is used by the cell. In this case, ATP passes into a state with lower energy into Adenosine DiPhosphate (ADP) and inorganic Phosphorus (P)
If a muscle produces work, then ATP is constantly broken down into ADP and inorganic phosphorus, releasing Energy (about 40-60 kJ/mol). For long-term work, it is necessary to restore ATP at the rate at which this substance is used by the cell.
The energy sources used for short-term, short-term and long-term work are different. Energy can be produced both anaerobically (oxygen-free) and aerobically (oxidatively). What qualities does an athlete develop when training in the aerobic or anaerobic zone, I wrote in the article ““.
There are three energy systems, ensuring human physical work:
- Alactate or phosphagen (anaerobic). It is associated with the processes of ATP resynthesis mainly due to the high-energy phosphate compound – Creatine Phosphate (CrP).
- Glycolytic (anaerobic). Provides resynthesis of ATP and KrP due to the reactions of anaerobic breakdown of glycogen and/or glucose to lactic acid (lactate).
- Aerobic (oxidative). The ability to perform work due to the oxidation of carbohydrates, fats, proteins while simultaneously increasing the delivery and utilization of oxygen in working muscles.
Energy sources for short-term operation.
The ATP molecule (Adenosine TriPhosphate) provides quickly accessible energy to the muscle. This energy is enough for 1-3 seconds. This source is used for instantaneous, maximum force operation.
ATP + H2O ⇒ ADP + P + Energy
In the body, ATP is one of the most frequently renewed substances; Thus, in humans, the lifespan of one ATP molecule is less than 1 minute. During the day, one ATP molecule goes through an average of 2000-3000 cycles of resynthesis (the human body synthesizes about 40 kg of ATP per day, but contains approximately 250 g at any given moment), that is, practically no ATP reserve is created in the body, and for normal life it is necessary to constantly synthesize new ATP molecules.
ATP is replenished by CrP (Creatine Phosphate), this is the second molecule of phosphate, which has high energy in the muscle. KrP donates a Phosphate molecule to an ADP molecule to form ATP, thereby allowing the muscle to work for a certain time.
It looks like this:
ADP+ KrP ⇒ ATP + Kr
The KrF reserve lasts up to 9 seconds. work. In this case, the power peak occurs at 5-6 seconds. Professional sprinters try to increase this tank (KrF reserve) even further through training to 15 seconds.
Both in the first case and in the second, the process of ATP formation occurs in anaerobic mode, without the participation of oxygen. Resynthesis of ATP due to CrP occurs almost instantly. This system has the greatest power compared to the glycolytic and aerobic ones and provides “explosive” work with maximum strength and speed of muscle contractions. This is what energy metabolism looks like during short-term work; in other words, this is how the alactic energy supply system of the body works.
Energy sources for short-term operation.
Where does the body get energy during short-term work? In this case, the source is animal carbohydrate, which is found in the muscles and liver of humans - glycogen. The process by which glycogen promotes ATP resynthesis and energy release is called Anaerobic glycolysis(Glycolytic energy supply system).
Glycolysis is a process of glucose oxidation in which two molecules of pyruvic acid (Pyruvate) are formed from one molecule of glucose. Further metabolism of pyruvic acid is possible in two ways - aerobic and anaerobic.
During aerobic work pyruvic acid (Pyruvate) is involved in metabolism and many biochemical reactions in the body. It is converted into Acetyl-coenzyme A, which participates in the Krebs Cycle ensuring respiration in the cell. In eukaryotes (cells of living organisms that contain a nucleus, that is, in human and animal cells), the Krebs cycle occurs inside the mitochondria (MC, this is the energy station of the cell).
Krebs cycle(tricarboxylic acid cycle) is a key stage in the respiration of all cells that use oxygen, it is the center of intersection of many metabolic pathways in the body. In addition to its energetic role, the Krebs Cycle has a significant plastic function. By participating in biochemical processes, it helps synthesize such important cellular compounds as amino acids, carbohydrates, fatty acids, etc.
If there is not enough oxygen, that is, the work is carried out in anaerobic mode, then pyruvic acid in the body undergoes anaerobic breakdown with the formation of lactic acid (lactate)
The glycolytic anaerobic system is characterized by high power. This process begins almost from the very beginning of work and reaches power after 15-20 seconds. work of maximum intensity, and this power cannot be maintained for more than 3 to 6 minutes. For beginners who are just starting to play sports, the power is barely enough for 1 minute.
Carbohydrates – glycogen and glucose – serve as energy substrates for providing muscles with energy. In total, the glycogen reserve in the human body is enough for 1-1.5 hours of work.
As mentioned above, as a result of the high power and duration of glycolytic anaerobic work, a significant amount of lactate (lactic acid) is formed in the muscles.
Glycogen ⇒ ATP + Lactic acid
Lactate from muscles enters the blood and binds to blood buffer systems to preserve the internal environment of the body. If the level of lactate in the blood increases, then the buffer systems at some point may not cope, which will cause a shift in the acid-base balance to the acidic side. When acidified, the blood becomes thick and the body cells cannot receive the necessary oxygen and nutrition. As a result, this causes inhibition of key enzymes of anaerobic glycolysis, up to complete inhibition of their activity. The rate of glycolysis itself, the alactic anaerobic process, and the power of work decreases.
The duration of work in anaerobic mode depends on the level of lactate concentration in the blood and the degree of resistance of muscles and blood to acid shifts.
Blood buffering capacity is the ability of blood to neutralize lactate. The more trained a person is, the greater his buffer capacity.
Energy sources for long-term operation.
Sources of energy for the human body during prolonged aerobic work, necessary for the formation of ATP, are muscle glycogen, blood glucose, fatty acids, and intramuscular fat. This process is triggered by prolonged aerobic work. For example, fat burning (fat oxidation) in beginning runners begins after 40 minutes of running in the 2nd pulse zone (PZ). For athletes, the oxidation process starts within 15-20 minutes of running. There is enough fat in the human body for 10-12 hours of continuous aerobic work.
When exposed to oxygen, molecules of glycogen, glucose, and fat are broken down, synthesizing ATP with the release of carbon dioxide and water. Most reactions occur in the mitochondria of the cell.
Glycogen + Oxygen ⇒ ATP + Carbon dioxide+ Water
The formation of ATP using this mechanism occurs more slowly than with the help of energy sources used for short-term and short-term work. It takes 2 to 4 minutes before the cell's need for ATP is completely satisfied by the aerobic process discussed. This delay is caused by the time it takes for the heart to begin increasing its supply of oxygenated blood to the muscles at the rate necessary to meet the muscles' ATP needs.
Fat + Oxygen ⇒ ATP + Carbon dioxide + Water
The fat oxidation factory in the body is the most energy-intensive. Since during the oxidation of carbohydrates, 38 molecules of ATP are produced from 1 molecule of glucose. And when 1 molecule of fat is oxidized, it produces 130 molecules of ATP. But this happens much more slowly. In addition, the production of ATP through fat oxidation requires more oxygen than the oxidation of carbohydrates. Another feature of the oxidative, aerobic factory is that it gains momentum gradually, as oxygen delivery increases and the concentration of fatty acids released from adipose tissue in the blood increases.
More useful information and articles you can find.
If you imagine all the energy-producing systems (energy metabolism) in the body in the form of fuel tanks, then they will look like this:
- The smallest tank is Creatine Phosphate (it's like 98 gasoline). It is located closer to the muscle and starts working quickly. This “gasoline” lasts for 9 seconds. work.
- Middle tank – Glycogen (92 petrol). This tank is located a little further in the body and fuel comes from it from 15-30 seconds physical work. This fuel is enough for 1-1.5 hours of operation.
- Big Tank – Fat ( diesel fuel). This tank is located far away and it will take 3-6 minutes before fuel starts flowing from it. The reserve of fat in the human body for 10-12 hours of intense, aerobic work.
I didn’t come up with all this myself, but took extracts from books, literature, and Internet resources and tried to convey it to you succinctly. If you have any questions, write.
1. What words are missing from the sentence and replaced with letters (a-d)?
“The ATP molecule consists of a nitrogenous base (a), a five-carbon monosaccharide (b) and (c) an acid residue (d).”
The following words are replaced by letters: a – adenine, b – ribose, c – three, d – phosphoric.
2. Compare the structure of ATP and the structure of a nucleotide. Identify similarities and differences.
In fact, ATP is a derivative of the adenyl nucleotide of RNA (adenosine monophosphate, or AMP). The molecules of both substances include the nitrogenous base adenine and the five-carbon sugar ribose. The differences are due to the fact that the adenyl nucleotide of RNA (as in any other nucleotide) contains only one phosphoric acid residue, and there are no high-energy (high-energy) bonds. The ATP molecule contains three phosphoric acid residues, between which there are two high-energy bonds, so ATP can act as a battery and energy carrier.
3. What is the process of ATP hydrolysis? ATP synthesis? What is biological role ATP?
During the process of hydrolysis, one phosphoric acid residue is removed from the ATP molecule (dephosphorylation). In this case, the high-energy bond is broken, 40 kJ/mol of energy is released and ATP is converted into ADP (adenosine diphosphoric acid):
ATP + H 2 O → ADP + H 3 PO 4 + 40 kJ
ADP can undergo further hydrolysis (which rarely occurs) with the elimination of another phosphate group and the release of a second “portion” of energy. In this case, ADP is converted into AMP (adenosine monophosphoric acid):
ADP + H 2 O → AMP + H 3 PO 4 + 40 kJ
ATP synthesis occurs as a result of the addition of a phosphoric acid residue to the ADP molecule (phosphorylation). This process occurs mainly in mitochondria and chloroplasts, partly in the hyaloplasm of cells. To form 1 mole of ATP from ADP, at least 40 kJ of energy must be expended:
ADP + H 3 PO 4 + 40 kJ → ATP + H 2 O
ATP is a universal storehouse (battery) and carrier of energy in the cells of living organisms. In almost all biochemical processes occurring in cells that require energy, ATP is used as an energy supplier. Thanks to the energy of ATP, new molecules of proteins, carbohydrates, lipids are synthesized, active transport of substances is carried out, the movement of flagella and cilia occurs, cell division occurs, muscles work, a constant body temperature is maintained in warm-blooded animals, etc.
4. What connections are called macroergic? What functions can substances containing high-energy bonds perform?
Macroergic bonds are those whose rupture releases a large amount of energy (for example, the rupture of each macroergic ATP bond is accompanied by the release of 40 kJ/mol of energy). Substances containing high-energy bonds can serve as batteries, carriers and suppliers of energy for various life processes.
5. The general formula of ATP is C 10 H 16 N 5 O 13 P 3. When 1 mole of ATP is hydrolyzed to ADP, 40 kJ of energy is released. How much energy will be released during the hydrolysis of 1 kg of ATP?
● Let's calculate molar mass ATP:
M (C 10 H 16 N 5 O 13 P 3) = 12 × 10 + 1 × 16 + 14 × 5 + 16 × 13 + 31 × 3 = 507 g/mol.
● When 507 g of ATP (1 mol) is hydrolyzed, 40 kJ of energy is released.
This means that upon hydrolysis of 1000 g of ATP, the following will be released: 1000 g × 40 kJ: 507 g ≈ 78.9 kJ.
Answer: When 1 kg of ATP is hydrolyzed to ADP, about 78.9 kJ of energy will be released.
6. ATP molecules labeled with radioactive phosphorus 32 P at the last (third) phosphoric acid residue were introduced into one cell, and ATP molecules labeled with 32 P at the first (closest to ribose) residue were introduced into the other cell. After 5 minutes, the content of inorganic phosphate ion labeled with 32 R was measured in both cells. Where was it higher and why?
The last (third) phosphoric acid residue is easily cleaved off during the hydrolysis of ATP, and the first (closest to ribose) is not cleaved off even during the two-step hydrolysis of ATP to AMP. Therefore, the content of radioactive inorganic phosphate will be higher in the cell into which ATP, labeled at the last (third) phosphoric acid residue, was introduced.
There are about 70 trillion cells in the human body. For healthy growth, each of them needs helpers - vitamins. Vitamin molecules are small, but their deficiency is always noticeable. If it is difficult to adapt to the dark, you need vitamins A and B2, dandruff appears - there is not enough B12, B6, P, bruises do not heal for a long time - vitamin C deficiency. In this lesson you will learn how and where in the cell strategic a supply of vitamins, how vitamins activate the body, and also learn about ATP - the main source of energy in the cell.
Topic: Basics of cytology
Lesson: Structure and functions of ATP
As you remember, nucleic acidsconsist of nucleotides. It turned out that in a cell nucleotides can be in a bound state or in a free state. In a free state, they perform a number of functions important for the life of the body.
To such free ones nucleotides applies ATP molecule or adenosine triphosphoric acid(adenosine triphosphate). Like all nucleotides, ATP is composed of a five-carbon sugar - ribose, nitrogenous base - adenine, and, unlike DNA and RNA nucleotides, three phosphoric acid residues(Fig. 1).
Rice. 1. Three schematic representations of ATP
The most important ATP function is that it is a universal keeper and carrier energy in a cage.
All biochemical reactions in cells that require energy expenditure, ATP is used as its source.
When one residue of phosphoric acid is separated, ATP goes into ADF (adenosine diphosphate). If another phosphoric acid residue is separated (which happens in special cases), ADF goes into AMF(adenosine monophosphate) (Fig. 2).
Rice. 2. Hydrolysis of ATP and its conversion into ADP
When the second and third residues of phosphoric acid are separated, a large amount of energy is released, up to 40 kJ. That is why the bond between these phosphoric acid residues is called high-energy and is designated by the corresponding symbol.
When a regular bond is hydrolyzed, a small amount of energy is released (or absorbed), but when a high-energy bond is hydrolyzed, much more energy is released (40 kJ). The bond between ribose and the first phosphoric acid residue is not high-energy; its hydrolysis releases only 14 kJ of energy.
High-energy compounds can also be formed on the basis of other nucleotides, for example GTF(guanosine triphosphate) is used as an energy source in protein biosynthesis, takes part in signal transduction reactions, is a substrate for RNA synthesis during transcription, but ATP is the most common and universal source energy in the cell.
ATP contained as in the cytoplasm, so in the nucleus, mitochondria and chloroplasts.
Thus, we remembered what ATP is, what its functions are, and what a macroergic bond is.
Vitamins - biologically active organic compounds, which in small quantities are necessary to maintain vital processes in the cell.
They are not structural components of living matter, and are not used as a source of energy.
Most vitamins are not synthesized in the body of humans and animals, but enter it with food, some are synthesized in small quantities intestinal microflora and tissues (vitamin D is synthesized by the skin).
The need for vitamins by humans and animals is not the same and depends on factors such as gender, age, physiological state and environmental conditions. Not all animals need some vitamins.
For example, ascorbic acid, or vitamin C, is essential for humans and other primates. At the same time, it is synthesized in the body of reptiles (sailors took turtles on voyages to combat scurvy - vitamin C deficiency).
Vitamins were discovered at the end of the 19th century thanks to the work of Russian scientists N. I. Lunina And V. Pashutina, which showed that for proper nutrition it is necessary not only the presence of proteins, fats and carbohydrates, but also some other, at that time unknown, substances.
In 1912, a Polish scientist K. Funk(Fig. 3), while studying the components of rice husk, which protects against Beri-Beri disease (vitamin deficiency of vitamin B), suggested that the composition of these substances must necessarily include amine groups. It was he who proposed to call these substances vitamins, that is, the amines of life.
Later it was found that many of these substances do not contain amino groups, but the term vitamins has taken root well in the language of science and practice.
As individual vitamins were discovered, they were designated with Latin letters and were named depending on the functions performed. For example, vitamin E was called tocopherol (from ancient Greek τόκος - “childbirth”, and φέρειν - “to bring”).
Today, vitamins are divided according to their ability to dissolve in water or fat.
To water-soluble vitamins include vitamins H, C, P, IN.
To fat-soluble vitamins include A, D, E, K(can be remembered as the word: sneaker) .
As already noted, the need for vitamins depends on age, gender, the physiological state of the body and the environment. At a young age, there is a clear need for vitamins. A weakened body also requires large doses of these substances. With age, the ability to absorb vitamins decreases.
The need for vitamins is also determined by the body’s ability to utilize them.
In 1912, a Polish scientist Kazimir Funk obtained partially purified vitamin B1 - thiamine - from rice husks. It took another 15 years to obtain this substance in a crystalline state.
Crystalline vitamin B1 is colorless, has a bitter taste and is highly soluble in water. Thiamine is found in both plant and microbial cells. It is especially abundant in grain crops and yeast (Fig. 4).
Rice. 4. Thiamine in tablet form and in food
Thermal processing of food products and various additives destroy thiamine. With vitamin deficiency, pathologies of the nervous, cardiovascular and digestive systems. Vitamin deficiency leads to disruption of water metabolism and hematopoietic function. One of bright examples Thiamine vitamin deficiency is a development of Beri-Beri disease (Fig. 5).
Rice. 5. A person suffering from thiamine deficiency - beriberi disease
Vitamin B1 is widely used in medical practice to treat various nervous diseases and cardiovascular disorders.
In baking, thiamine, together with other vitamins - riboflavin and nicotinic acid, is used for vitaminization bakery products.
In 1922 G. Evans And A. Bisho discovered a fat-soluble vitamin, which they called tocopherol or vitamin E (literally: “promoting childbirth”).
Vitamin E in pure form- oily liquid. It is widespread in cereal crops, for example in wheat. There is a lot of it in vegetable and animal fats (Fig. 6).
Rice. 6. Tocopherol and products that contain it
There is a lot of vitamin E in carrots, eggs and milk. Vitamin E is antioxidant, that is, it protects cells from pathological oxidation, which leads to aging and death. It is the “vitamin of youth”. The vitamin is of great importance for the reproductive system, which is why it is often called the vitamin of reproduction.
As a result, vitamin E deficiency, first of all, leads to disruption of embryogenesis and the functioning of the reproductive organs.
The production of vitamin E is based on its isolation from wheat germ using the method of alcohol extraction and distillation of solvents at low temperatures.
In medical practice, both natural and synthetic drugs are used - tocopherol acetate in vegetable oil, enclosed in a capsule (the famous “fish oil”).
Vitamin E preparations are used as antioxidants for radiation exposure and other pathological conditions associated with increased levels of ionized particles and reactive oxygen species in the body.
In addition, vitamin E is prescribed to pregnant women, and is also used in complex therapy for the treatment of infertility, muscular dystrophy and some liver diseases.
Vitamin A (Fig. 7) was discovered N. Drummond in 1916.
This discovery was preceded by observations of the presence of a fat-soluble factor in food necessary for full development farm animals.
It is not for nothing that Vitamin A occupies first place in the vitamin alphabet. It participates in almost all life processes. This vitamin is necessary to restore and maintain good vision.
It also helps develop immunity to many diseases, including colds.
Without vitamin A, healthy skin epithelium is impossible. If you have goose bumps, which most often appear on the elbows, hips, knees, legs, dry skin on your hands, or other similar phenomena, this means that you lack vitamin A.
Vitamin A, like vitamin E, is essential for normal functioning sex glands (gonads). Vitamin A hypovitaminosis causes damage reproductive system and respiratory organs.
One of the specific consequences of a lack of vitamin A is a violation of the vision process, in particular a decrease in the ability of the eyes to adapt to dark conditions - night blindness. Vitamin deficiency leads to xerophthalmia and destruction of the cornea. The latter process is irreversible and is characterized by complete loss of vision. Hypervitaminosis leads to inflammation of the eyes and hair loss, loss of appetite and complete exhaustion of the body.
Rice. 7. Vitamin A and foods that contain it
Group A vitamins are primarily found in products of animal origin: liver, fish oil, in oil, in eggs (Fig. 8).
Rice. 8. Vitamin A content in foods of plant and animal origin
Products of plant origin contain carotenoids, which are converted into vitamin A in the human body under the action of the enzyme carotinase.
Thus, today you became acquainted with the structure and functions of ATP, and also remembered the importance of vitamins and found out how some of them are involved in vital processes.
With insufficient intake of vitamins into the body, primary vitamin deficiency develops. Different foods contain different amounts of vitamins.
For example, carrots contain a lot of provitamin A (carotene), cabbage contains vitamin C, etc. Hence the need for a balanced diet, including a variety of foods of plant and animal origin.
Avitaminosis under normal nutritional conditions it is very rare, much more common hypovitaminosis, which are associated with insufficient intake of vitamins from food.
Hypovitaminosis can occur not only as a result of an unbalanced diet, but also as a consequence of various pathologies from gastrointestinal tract or liver, or as a result of various endocrine or infectious diseases which lead to impaired absorption of vitamins in the body.
Some vitamins are produced by intestinal microflora (gut microbiota). Suppression of biosynthetic processes as a result of action antibiotics may also lead to the development hypovitaminosis, as a consequence dysbacteriosis.
Excessive use of dietary vitamin supplements, as well as medicines containing vitamins, leads to the occurrence of a pathological condition - hypervitaminosis. This is especially true for fat-soluble vitamins, such as A, D, E, K.
Homework
1. What substances are called biologically active?
2. What is ATP? What is special about the structure of the ATP molecule? What types chemical bond exist in this complex molecule?
3. What are the functions of ATP in the cells of living organisms?
4. Where does ATP synthesis occur? Where does ATP hydrolysis occur?
5. What are vitamins? What are their functions in the body?
6. How do vitamins differ from hormones?
7. What classifications of vitamins do you know?
8. What are vitamin deficiency, hypovitaminosis and hypervitaminosis? Give examples of these phenomena.
9. What diseases can be a consequence of insufficient or excessive intake of vitamins in the body?
10. Discuss your menu with friends and relatives, calculate using additional information about the content of vitamins in different foods, whether you get enough vitamins.
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Bibliography
1. Kamensky A. A., Kriksunov E. A., Pasechnik V. V. General biology 10-11 grade Bustard, 2005.
2. Belyaev D.K. Biology 10-11 grade. General biology. A basic level of. - 11th ed., stereotype. - M.: Education, 2012. - 304 p.
3. Agafonova I. B., Zakharova E. T., Sivoglazov V. I. Biology 10-11 grade. General biology. A basic level of. - 6th ed., add. - Bustard, 2010. - 384 p.
