Determination of the respiratory coefficient (RK) of plants. Determination of respiratory coefficient Respiratory coefficient its value value
respiratory coefficient (RK)
the ratio of the volume of carbon dioxide released through the lungs to the volume of oxygen absorbed during the same time; the value of D.c. when the subject is at rest depends on the type of food substances oxidized in the body.
Encyclopedic Dictionary, 1998
respiratory quotient
the ratio of the volume of carbon dioxide released during breathing during a certain time to the volume of oxygen absorbed during the same time. Characterizes the features of gas exchange and metabolism in animals and plants. In a healthy person it is approximately 0.85.
Respiratory coefficient
the ratio of the volume of carbon dioxide released from the body to the volume of oxygen absorbed during the same time. Indicated by:
Determination of DC is important for studying the characteristics of gas exchange and metabolism in animals and plant organisms. When carbohydrates are oxidized in the body and oxygen is fully available, DC is 1, fats ≈ 0.7, proteins ≈ 0.8. In a healthy person at rest, DC is 0.85 ╠ 0.1; during moderate work, as well as in animals that eat predominantly plant foods, it approaches 1. In humans, during very long work, fasting, in carnivores (predators), as well as during hibernation, when, due to the limited reserves of carbohydrates in the body, dissimilation increases fat, DC is about 0.7. DC exceeds 1 with intensive deposition in the body of fats formed from carbohydrates supplied with food (for example, in humans when restoring normal weight after fasting, after long-term illnesses, as well as in animals during fattening). The DC increases to 2 with intense work and hyperventilation of the lungs, when additional CO2, which was in a bound state, is released from the body. DC reaches even greater values in anaerobes, in which most of the released CO2 is formed by oxygen-free oxidation (fermentation). DK below 0.7 occurs in diseases associated with metabolic disorders, after heavy physical work.
In plants, DK depends on the chemical nature of the respiratory substrate, the content of CO2 and O2 in the atmosphere and other factors, thus characterizing the specifics and conditions of respiration. When the cell uses carbohydrates for respiration (cereal seedlings), the DC is approximately 1, fats and proteins (germinating oilseeds and legumes) ≈ 0.4≈0.7. With a lack of O2 and difficult access (seeds with a hard shell), the DC is 2≈3 or more; high DC is also characteristic of growth point cells.
(DC) is the ratio of the volume of carbon dioxide released during respiration to the volume of oxygen absorbed.
The value of the plant respiratory coefficient
DC value indicates both the nature of the material oxidized during respiration and the type of respiration; it can be equal to, greater than, or less than one. During the oxidation of carbohydrates, the volumes of exchanged gases, carbon dioxide and oxygen, are equal and the ratio C0 2: 0 2 is equal to unity. In this case, the oxygen consumed during respiration is used only for the oxidation of carbon to carbon dioxide, because the ratio of hydrogen and oxygen in the glucose molecule is such that for the oxidation of hydrogen to water, there is enough oxygen in the sugar molecule itself. When a number of organic acids are oxidized, the respiratory coefficient of plants is greater than one. Thus, oxalic acid is a compound richer in oxygen than carbohydrates. The oxygen present in the molecule is not only sufficient for the oxidation of hydrogen to water, but part of it remains for the oxidation of carbon; therefore, for the complete oxidation of two molecules of oxalic acid, one molecule of oxygen is sufficient: 2C 2 H 2 O 4 + O 2 → 4CO 2 + 2H 2 O, DC (4CO 2: O 2) in this case is equal to 4. In cases where the plant respires due to proteins or fats, the molecule of which contains a lot of hydrogen and carbon and little oxygen; DC is less than one, since in order to oxidize all the carbon and hydrogen found in these compounds, it is necessary to absorb a large amount of oxygen. When stearic acid is oxidized, the oxidation reaction will proceed as follows: C 18 H 26 O 2 + 26 O 2 → 18 CO 2 + 18 H 2 O. DC (18 CO 2: 26 O 2) is 0.69. Thus, in the case of the oxidation of carbohydrates, DC is equal to one, organic acids - more than one, proteins and fats - less than one.
Thermal effect during plant respiration
Thermal effect will have the opposite value of DC: the maximum thermal effect will be during the oxidation of fats, because they are the most reduced compounds. The dependence of the DC value on the nature of the respiratory material is observed only when there is enough oxygen in the environment and plant tissues. However, during the oxidation of the same respiratory material, but with a lack of oxygen in the environment and plant tissues, the DC values can also change. If there is little oxygen, then oxidation does not proceed to completion and, in addition to carbon dioxide and water, organic acids are formed, which are more oxidized than carbohydrates. In this case, DC will be less than one, since part of the absorbed oxygen will remain in the molecules of the formed organic acids, while less carbon dioxide will be released. Less energy will be released, since some of it will be stored in organic acids.1. What process ensures the release of energy in the body? What is its essence?
Dissimilation (catabolism), i.e., the breakdown of cellular structures and compounds of the body with the release of energy and decay products.
2. What nutrients provide energy in the body?
Carbohydrates, fats and proteins.
3. Name the main methods for determining the amount of energy in a sample of a product.
Physical calorimetry; physicochemical methods for determining the amount of nutrients in a sample with subsequent calculation of the energy contained in it; according to tables.
4. Describe the essence of the method of physical calorimetry.
A sample of the product is burned in the calorimeter, and then the released energy is calculated based on the degree of heating of the water and the calorimeter material.
5. Write a formula for calculating the amount of heat released during combustion of a product in a calorimeter. Decipher its symbols.
Q = MvSv (t 2 - t 1) + MkSk (t 2 - t 1) - Qо,
where Q is the amount of heat, M is the mass (w - water, k - calorimeter), (t 2 - t 1) is the temperature difference between water and calorimeter after and before combustion of the sample, C is the specific heat capacity, Qo is the amount of heat generated by the oxidizer .
6. What are the physical and physiological caloric coefficients of a nutrient?
The amount of heat released during the combustion of 1 g of a substance in a calorimeter and in the body, respectively.
7. How much heat is released when 1 g of proteins, fats and carbohydrates are burned in a calorimeter?
1g protein – 5.85 kcal (24.6 kJ), 1g fat – 9.3 kcal (38.9 kJ), 1g carbohydrates – 4.1 kcal (17.2 kJ).
8. Formulate Hess’s law of thermodynamics, on the basis of which the energy entering the body is calculated based on the amount of digested proteins, fats and carbohydrates.
The thermodynamic effect depends only on the heat content of the initial and final reaction products and does not depend on the intermediate transformations of these substances.
9. How much heat is released during the oxidation of 1 g of proteins, 1 g of fats and 1 g of carbohydrates in the body?
1 g of proteins – 4.1 kcal (17.2 kJ), 1 g of fats – 9.3 kcal (38.9 kJ), 1 g of carbohydrates – 4.1 kcal (17.2 kJ).
10. Explain the reason for the difference between the physical and physiological caloric coefficients for proteins. In which case is it greater?
In the calorimeter (physical coefficient), the protein decomposes to the final products - CO 2, H 2 O and NH 3 with the release of all the energy contained in them. In the body (physiological coefficient), proteins break down into CO 2, H 2 O, urea and other substances of protein metabolism, which contain energy and are excreted in the urine.
The content of proteins, fats and carbohydrates in food products is determined, their amount is multiplied by the corresponding physiological caloric coefficients, summed up and 10% is subtracted from the sum, which is not absorbed in the digestive tract (losses in feces).
12. Calculate (in kcal and kJ) the energy intake when 10 g of proteins, fats and carbohydrates are taken into the body with food.
Q = 4.110 + 9.310 + 4.110 = 175 kcal. (175 kcal - 17.5 kcal) x 4.2 kJ, where 17.5 kcal is the energy of undigested nutrients (losses in feces - about 10%). Total: 157.5 kcal (661.5 kJ).
Calorimetry: direct (Atwater-Benedict method); indirect, or indirect (methods of Krogh, Shaternikov, Douglas - Holden).
14. What is the principle of direct calorimetry based on?
On direct measurement of the amount of heat generated by the body.
15. Briefly describe the design and operating principle of the Atwater-Benedict camera.
The chamber in which the subject is placed is thermally isolated from the environment; its walls do not absorb heat; inside they are radiators through which water flows. Based on the degree of heating of a certain mass of water, the amount of heat consumed by the body is calculated.
16. What is the principle of indirect (indirect) calorimetry based on?
By calculating the amount of energy released according to gas exchange data (absorbed O 2 and released CO 2 per day).
17. Why can the amount of energy released by the body be calculated based on gas exchange rates?
Because the amount of O 2 consumed by the body and CO 2 released corresponds exactly to the amount of oxidized proteins, fats and carbohydrates, and therefore the energy consumed by the body.
18. What coefficients are used to calculate energy consumption by indirect calorimetry?
Respiratory coefficient and caloric equivalent of oxygen.
19. What is called the respiratory coefficient?
The ratio of the volume of carbon dioxide released by the body to the volume of oxygen consumed during the same time.
20. Calculate the respiratory coefficient (RC) if it is known that the inhaled air contains 17% oxygen and 4% carbon dioxide.
Since atmospheric air contains 21% O 2, the percentage of absorbed oxygen is 21% - 17%, i.e. 4%. CO 2 in exhaled air is also 4%. From here
21. What does the respiratory coefficient depend on?
22. What is the respiratory coefficient during the oxidation in the body to the final products of proteins, fats and carbohydrates?
During the oxidation of proteins – 0.8, fats – 0.7, carbohydrates – 1.0.
23. Why is the respiratory quotient lower for fats and proteins than for carbohydrates?
More O 2 is consumed for the oxidation of proteins and fats, since they contain less intramolecular oxygen than carbohydrates.
24. What value does a person’s respiratory quotient approach at the beginning of intense physical work? Why?
To one, because the source of energy in this case is mainly carbohydrates.
25. Why is a person’s respiratory coefficient greater than one in the first minutes after intense and prolonged physical work?
Because more CO 2 is released than O 2 is consumed, since lactic acid accumulated in the muscles enters the blood and displaces CO 2 from bicarbonates.
26. What is called the caloric equivalent of oxygen?
The amount of heat released by the body when consuming 1 liter of O 2.
27. What does the caloric equivalent of oxygen depend on?
From the ratio of proteins, fats and carbohydrates oxidized in the body.
28. What is the caloric equivalent of oxygen during the oxidation in the body (in the process of dissimilation) of proteins, fats and carbohydrates?
For proteins – 4.48 kcal (18.8 kJ), for fats – 4.69 kcal (19.6 kJ), for carbohydrates – 5.05 kcal (21.1 kJ).
29. Briefly describe the process of determining energy consumption using the Douglas-Holden method (full gas analysis).
Within a few minutes, the subject inhales atmospheric air, and the exhaled air is collected in a special bag, its quantity is measured and gas analysis is carried out to determine the volume of oxygen consumed and CO 2 released. The respiratory coefficient is calculated, with the help of which the corresponding caloric equivalent of O 2 is found from the table, which is then multiplied by the volume of O 2 consumed over a given period of time.
30. Briefly describe M. N. Shaternikov’s method for determining energy expenditure in animals in an experiment.
The animal is placed in a chamber into which oxygen is supplied as it is consumed. CO 2 released during respiration is absorbed by alkali. The energy released is calculated based on the amount of O2 consumed and the average caloric equivalent of O2: 4.9 kcal (20.6 kJ).
31. Calculate energy consumption in 1 minute if it is known that the subject consumed 300 ml of O 2. The respiratory coefficient is 1.0.
DK = 1.0, it corresponds to the caloric equivalent of oxygen equal to 5.05 kcal (21.12 kJ). Therefore, energy consumption per minute = 5.05 kcal x 0.3 = 1.5 kcal (6.3 kJ).
32. Briefly describe the process of determining energy consumption using the Krogh method in humans (incomplete gas analysis).
The subject inhales oxygen from the metabolimeter bag, the exhaled air returns to the same bag, having previously passed through a CO 2 absorber. Based on the readings of the metabolimeter, the O2 consumption is determined and multiplied by the caloric equivalent of oxygen 4.86 kcal (20.36 kJ).
33. Name the main differences in calculating energy consumption using the Douglas-Holden and Krogh methods.
The Douglas–Holden method involves calculating energy consumption based on data from a complete gas analysis; Krogh's method - only by the volume of oxygen consumed using the caloric equivalent of oxygen characteristic of basal metabolic conditions.
34. What is called the basal metabolism?
Minimum energy consumption that ensures homeostasis under standard conditions: while awake, with maximum muscular and emotional rest, on an empty stomach (12 - 16 hours without food), at a comfortable temperature (18 - 20C).
35. Why is basal metabolism determined under standard conditions: maximum muscular and emotional rest, on an empty stomach, at a comfortable temperature?
Because physical activity, emotional stress, food intake and changes in ambient temperature increase the intensity of metabolic processes in the body (energy consumption).
36. What processes consume basal metabolic energy in the body?
To ensure the vital functions of all organs and tissues of the body, cellular synthesis, and to maintain body temperature.
37. What factors determine the value of the proper (average) basal metabolic rate of a healthy person?
Gender, age, height and body mass (weight).
38. What factors, besides gender, weight, height and age, determine the value of the true (real) basal metabolic rate of a healthy person?
Living conditions to which the body is adapted: permanent residence in a cold climate zone increases basal metabolism; long-term vegetarian diet – reduces.
39. List the ways to determine the amount of proper basal metabolism in a person. What method is used to determine the value of a person’s true basal metabolic rate in practical medicine?
According to tables, according to formulas, according to nomograms. Krogh method (incomplete gas analysis).
40. What is the value of basal metabolism in men and women per day, as well as per 1 kg of body weight per day?
For men, 1500 – 1700 kcal (6300 – 7140 kJ), or 21 – 24 kcal (88 – 101 kJ)/kg/day. Women have approximately 10% less than this value.
41. Is the basal metabolic rate calculated per 1 m 2 of body surface and per 1 kg of body weight the same in warm-blooded animals and humans?
When calculated per 1 m2 of body surface in warm-blooded animals of different species and humans, the indicators are approximately equal, when calculated per 1 kg of mass they are very different.
42. What is called a working exchange?
The combination of basal metabolism and additional energy expenditure that ensures the functioning of the body in various conditions.
43. List the factors that increase energy consumption by the body. What is called the specific dynamic effect of food?
Physical and mental stress, emotional stress, changes in temperature and other environmental conditions, specific dynamic effects of food (increased energy consumption after eating).
44. By what percentage does the body’s energy consumption increase after eating protein and mixed foods, fats and carbohydrates?
After eating protein foods - by 20 - 30%, mixed foods - by 10 - 12%.
45. How does ambient temperature affect the body’s energy expenditure?
Temperature changes in the range of 15 – 30C do not significantly affect the body’s energy consumption. At temperatures below 15C and above 30C, energy consumption increases.
46. How does metabolism change at ambient temperatures below 15? What does it matter?
Increasing. This prevents the body from cooling down.
47. What is called the body’s efficiency during muscular work?
Expressed as a percentage, the ratio of the energy equivalent to useful mechanical work to the total energy expended in performing that work.
48. Give a formula for calculating the coefficient of performance (efficiency) in a person during muscular work, indicate its average value, decipher the elements of the formula.
where A is energy equivalent to useful work, C is total energy consumption, e is energy consumption for the same period of time at rest. The efficiency is 20%.
49. What animals are called poikilothermic and homeothermic?Poikilothermic animals (cold-blooded) - with an unstable body temperature, depending on the ambient temperature; homeothermic (warm-blooded) - animals with a constant body temperature that does not depend on the ambient temperature.
50. What is the importance of constancy of body temperature for the body? In which organs does the process of heat formation occur most intensively?
Provides a high level of vital activity relatively regardless of ambient temperature. In muscles, lungs, liver, kidneys.
51. Name the types of thermoregulation. Formulate the essence of each of them.
Chemical thermoregulation - regulation of body temperature by changing the intensity of heat production; physical thermoregulation - by changing the intensity of heat transfer.
52. What processes provide heat transfer?
Heat radiation (radiation), heat evaporation, heat conduction, convection.
53. How does the lumen of skin blood vessels change when the ambient temperature decreases and increases? What is the biological significance of this phenomenon?
When the temperature drops, the blood vessels in the skin narrow. As the ambient temperature rises, the blood vessels in the skin dilate. The fact is that changing the width of the lumen of blood vessels, regulating heat transfer, helps maintain a constant body temperature.
54. How and why does heat production and heat transfer change with strong stimulation of the sympathoadrenal system?
Heat production will increase due to stimulation of oxidative processes, and heat transfer will decrease as a result of narrowing of skin vessels.
55. List the areas of localization of thermoreceptors.
Skin, cutaneous and subcutaneous vessels, internal organs, central nervous system.
56. In what parts and structures of the central nervous system are thermoreceptors located?
In the hypothalamus, reticular formation of the midbrain, in the spinal cord.
57. In which parts of the central nervous system are thermoregulation centers located? Which structure of the central nervous system is the highest center of thermoregulation?
In the hypothalamus and spinal cord. Hypothalamus.
58. What changes will occur in the body with a long-term absence of fats and carbohydrates in the diet, but with an optimal intake of protein from food (80 - 100 g per day)? Why?
There will be an excess of nitrogen consumption by the body over intake, and weight loss, since energy costs will be covered mainly by proteins and fat reserves that are not replenished.
59. In what quantity and in what ratio should proteins, fats and carbohydrates be contained in the diet of an adult (average version)?
Proteins – 90 g, fats – 110 g, carbohydrates – 410 g. Ratio 1: 1, 2: 4, 6.
60. How does the state of the body change with excess fat intake?
Obesity and atherosclerosis develop (prematurely). Obesity is a risk factor for the development of cardiovascular diseases and their complications (myocardial infarction, stroke, etc.), and reduced life expectancy.
1. What is the ratio of basal metabolic values in children of the first 3–4 years of life, during puberty, at the age of 18–20 years and adults (kcal/kg/day)?
Up to 3–4 years of age, children have approximately 2 times more, during puberty – 1.5 times more than adults. At 18–20 years old it corresponds to the adult norm.
2. Draw a graph of changes in basal metabolic rate in boys with age (in girls, basal metabolic rate is 5% lower).
3. What explains the high intensity of oxidative processes in a child?
A higher level of metabolism of young tissues, a relatively large surface area of the body and, naturally, greater energy expenditure to maintain a constant body temperature, increased secretion of thyroid hormones and norepinephrine.
4. How do energy costs for growth change depending on the age of the child: up to 3 months of life, before the onset of puberty, during puberty?
They increase in the first 3 months after birth, then gradually decrease, and increase again during puberty.
5. What does the total energy expenditure of a 1-year-old child consist of and how is it distributed as a percentage compared to an adult?
In a child: 70% falls on the basal metabolism, 20% on movement and maintaining muscle tone, 10% on the specific dynamic effect of food. In an adult: 50 – 40 – 10%, respectively.
6. Do adults or children 3–5 years of age expend more energy when performing muscular work to achieve the same useful result, by how many times and why?
Children, 3 to 5 times, since they have less perfect coordination, which leads to excessive movements, resulting in significantly less useful work for children.
7. How does energy expenditure change when a child cries, by what percentage, and as a result of what?
Increases by 100–200% due to increased heat production as a result of emotional arousal and increased muscle activity.
8. What part (in percentage) of an infant’s energy expenditure is provided by proteins, fats, and carbohydrates? (compare with the adult norm).
Due to proteins - 10%, due to fats - 50%, due to carbohydrates - 40%. In adults – 20 – 30 – 50%, respectively.
9. Why do children, especially in infancy, quickly overheat when the ambient temperature rises? Do children tolerate increases or decreases in ambient temperature more easily?
Because children have increased heat production, insufficient sweating and, consequently, heat evaporation, an immature thermoregulation center. Demotion.
10. Name the immediate cause and explain the mechanism of rapid cooling of children (especially infants) when the ambient temperature drops.
Increased heat transfer in children due to a relatively large body surface, abundant blood supply to the skin, insufficient thermal insulation (thin skin, lack of subcutaneous fat) and immaturity of the thermoregulation center; insufficient vasoconstriction.
11. At what age does a child begin to experience daily temperature fluctuations, how do they differ from those in adults, and at what age do they reach adult norms?
At the end of 1 month of life; they are insignificant and reach the adult norm by five years.
12. What is a child’s temperature “comfort zone”, what temperature is it within, what is this indicator for adults?
The external temperature at which individual fluctuations in the temperature of a child’s skin are least pronounced is in the range of 21 – 22 o C, in an adult – 18 – 20 o C.
13. Which thermoregulation mechanisms are most ready to function at the time of birth? Under what conditions can the mechanisms of trembling thermogenesis be activated in newborns?
Increased heat generation, predominantly of non-shivering origin (high metabolism), sweating. Under conditions of extreme cold exposure.
14. In what ratio should proteins, fats and carbohydrates be contained in the diet of children aged three and six months, 1 year, over one year and adults?
Up to 3 months – 1: 3: 6; at 6 months – 1: 2: 4. At the age of 1 year and older – 1: 1, 2: 4, 6, i.e., the same as in adults.
15. Name the features of the metabolism of mineral salts in children. What is this connected with?
There is retention of salts in the body, especially increased need for calcium, phosphorus and iron, which is associated with the growth of the body.
11 Energy exchange
An indispensable condition for maintaining life is that organisms receive energy from the external environment, and although the primary source of energy for all living things is the Sun, only plants are capable of directly using its radiation. Through photosynthesis, they convert the energy of sunlight into the energy of chemical bonds. Animals and humans get the energy they need by eating plant foods. (For carnivores and partly for omnivores, other animals - herbivores - serve as a source of energy.)
Animals can also directly receive energy from the sun's rays; for example, poikilothermic animals maintain their body temperature in this way. However, heat (received from the external environment and generated in the body itself) cannot be converted into any other type of energy. Living organisms, unlike technical devices, are fundamentally incapable of this. A machine that uses the energy of chemical bonds (for example, an internal combustion engine) first converts it into heat and only then into work: the chemical energy of the fuel → warm → work (expansion of gas in the cylinder and movement of the piston). In living organisms, only this scheme is possible: chemical energy → Job.
So, the energy of chemical bonds in the molecules of food substances is practically the only source of energy for an animal organism, and thermal energy can only be used by it to maintain its body temperature. In addition, heat, due to rapid dissipation in the environment, cannot be stored in the body for a long period. If excess heat occurs in the body, then for homeothermic animals this becomes a serious problem and sometimes even threatens their life (see Section 11.3).
11.1. Sources of energy and ways of its transformation in the body
A living organism is an open energy system: it receives energy from the environment (almost exclusively in the form of chemical bonds), converts it into heat or work, and in this form returns it to the environment.
Components of nutrients that enter the blood from the gastrointestinal tract (for example, glucose, fatty acids or amino acids) are not themselves capable of directly transferring the energy of their chemical bonds to its consumers, for example, the potassium-sodium pump or muscle actin and myosin. There is a universal intermediary between food “energy carriers” and “consumers” of energy - adenosine triphosphate (ATP). He is the one direct source energy for any processes in living things
body. The ATP molecule is a combination of adenine, ribose and three phosphate groups (Fig. 11.1).
The bonds between acid residues (phosphates) contain a significant amount of energy. By splitting off the terminal phosphate under the action of the enzyme ATPase, ATP is converted into adenosine diphosphate (ADP). This releases 7.3 kcal/mol of energy. The energy of chemical bonds in food molecules is used for the resynthesis of ATP from ADP. Let's consider this process using glucose as an example (Fig. 11.2).
The first stage of glucose utilization is glycolysis During this process, a glucose molecule is first converted into pyruvic acid (pyruvat), while providing energy for ATP resynthesis. Pyruvate is then converted to acetyl coenzyme A - initial product for the next stage of recycling - Krebs cycle. The multiple transformations of substances that make up the essence of this cycle provide additional energy for the resynthesis of ATP and end with the release of hydrogen ions. The third stage begins with the transfer of these ions into the respiratory chain - oxidative phosphorylation, as a result of which ATP is also formed.
Taken together, all three stages of recycling (glycolysis, Krebs cycle and oxidative phosphorylation) constitute the process tissue respiration. It is fundamentally important that the first stage (glycolysis) takes place without the use of oxygen (anaerobic respiration) and leads to the formation of only two ATP molecules. The two subsequent stages (Krebs cycle and oxidative phosphorylation) can only occur in an oxygen environment (aerobic respiration). Complete utilization of one glucose molecule results in the appearance of 38 ATP molecules.
There are organisms that not only do not require oxygen, but also die in an oxygen (or air) environment - obligate anaerobes. These, for example, include bacteria that cause gas gangrene (Clostridium perfringes), tetanus (C. tetani), botulism (C. botulinum), etc.
In animals, anaerobic processes are an auxiliary type of respiration. For example, with intense and frequent muscle contractions (or with static contractions), the delivery of oxygen by the blood lags behind the needs of the muscle cells. At this time, ATP formation occurs anaerobically with the accumulation of pyruvate, which is converted into lactic acid (lactate). Growing oxygen debt. The cessation or weakening of muscle work eliminates the discrepancy between the tissue's need for oxygen and the possibilities of its delivery; lactate is converted into pyruvate, the latter either through the stage of acetyl coenzyme A is oxidized in the Krebs cycle to carbon dioxide, or through gluconeogenesis it turns into glucose.
According to the second law of thermodynamics, any transformation of energy from one type to another occurs with the obligatory formation of a significant amount of heat, which is then dissipated in the surrounding space. Therefore, the synthesis of ATP and the transfer of energy from ATP to the actual “energy consumers” occur with the loss of approximately half of it in the form of heat. Simplifying, we can represent these processes as follows (Fig. 11.3).
Approximately half of the chemical energy contained in food is immediately converted into heat and dissipated in space, the other half goes to the formation of ATP. With the subsequent breakdown of ATP, half of the released energy is again converted into heat. As a result, an animal and a person can spend no more than 1/4 of all energy consumed in the form of food to perform external work (for example, running or moving any objects in space). Thus, the efficiency of higher animals and humans (about 25%) is several times higher than, for example, the efficiency of a steam engine.
All internal work (except for the processes of growth and fat accumulation) quickly turns into heat. Examples: (a) the energy produced by the heart is converted into heat due to the resistance of blood vessels to the flow of blood; (b) the stomach does the work of secreting hydrochloric acid, the pancreas secretes bicarbonate ions, in the small intestine these substances interact, and the energy stored in them is converted into heat.
The results of external (useful) work performed by an animal or a person also ultimately turn into heat: the movement of bodies in space warms the air, erected structures collapse, giving up the energy embedded in them to the earth and air in the form of heat. The Egyptian pyramids are a rare example of how the energy of muscle contraction, expended almost 5,000 years ago, is still waiting for the inevitable transformation into heat.
Energy balance equation:
E = A + H + S,
Where E - the total amount of energy received by the body from food; A - external (useful) work; N - heat transfer; S- stored energy.
Energy losses through urine, sebum and other secretions are extremely small and can be neglected.
The respiratory coefficient is 18.10:24.70 = 0.73.[...]
The respiratory coefficient does not remain constant during normal fruit ripening. In the premenopausal stage it is approximately 1 and as it matures it reaches values of 1.2... 1.5. With deviations of ±0.25 from one, metabolic abnormalities are not yet observed in the fruits, and only with large deviations can physiological disorders be assumed. The intensity of respiration of individual layers of tissue of any fetus is not the same. In accordance with the greater activity of enzymes in the skin, respiration rates are many times greater in it than in parenchymal tissue (Hulme and Rhodes, 1939). With a decrease in oxygen content and an increase in the concentration of carbon dioxide in parenchyma cells, the intensity of respiration decreases with distance from the skin to the core of the fruit.[...]
Instrument for determining the respiratory coefficient, tweezers, strips of filter paper, hourglass for 2 minutes, glass cups, pipettes, glass rods, 250 ml conical flasks.[...]
The device for determining the respiratory coefficient consists of a large test tube with a tightly fitting rubber stopper, into which a measuring tube bent at a right angle with a graph paper scale is inserted.[...]
Oxygen consumption and its utilization coefficient were constant when p02 was reduced to 60 and 20% of the original (depending on the flow rate). At oxygen concentrations slightly above the critical level, the maximum volume of ventilation was maintained for a long time (for several hours). The volume of ventilation increased by 5.5 times, but unlike carp, it decreased starting from 22% of the level of water saturation with oxygen. The authors believe that a decrease in the volume of ventilation in fish under extreme hypoxia is a consequence of oxygen deficiency of the respiratory muscles. The ratio of respiratory rate and heart rate was 1.4 normally and 4.2 with oxygen deficiency. [...]
Introductory explanations. Advantages of the method: high sensitivity, which allows you to work with small samples of experimental material; the ability to observe the dynamics of gas exchange and simultaneously take into account the gas exchange of 02 and C02, which allows you to set the respiratory coefficient.[...]
Therefore, the pH value in the oxyteik decreases to almost 6.0, while in the aeration tank pH>7D. At maximum load, the power consumption for the oxytank, including the power of the oxygen production equipment is 1.3 m3/ (hp-h) and power aerator (Fig. 26.9), should be less than the power of the aerator for the aeration tank. This is explained by the high concentration of oxygen (above 60%) in all stages of the oxygen tank.[...]
Dynamics of carbon dioxide release (С?СО2), oxygen absorption ([...]
Marine and freshwater fish under these experimental conditions had approximately the same respiratory coefficient (RQ). The disadvantage of these data is that the author took a goldfish for comparison, which generally consumes little oxygen and can hardly serve as a standard of comparison.[...]
With regard to the gas exchange of hibernating insects, it should be said that the respiratory coefficient also decreases1. For example, Dreyer (1932) found that in the active state of the ant Formica ulkei Emery the respiratory coefficient was 0.874; when the ants became inactive before hibernation, the respiratory coefficient decreased to 0.782, and during the hibernation period the decrease reached 0.509-0.504. The Colorado potato beetle Leptinotarsa decemlineata Say. during the wintering period, the respiratory coefficient decreases to 0.492-0.596, while in the summer it is 0.819-0.822 (Ushatinskaya, 1957). This is explained by the fact that in the active state insects live mainly on protein and carbohydrate foods, while in hibernation they mainly consume fat, which requires less oxygen for oxidation. [...]
In sealed containers designed for pressure in the GP RK. d = 1962 Pa (200 mm water column), with high turnover rates, the duration of idle time for the tank with the “dead” residue before filling begins can be so short that the breathing valve does not have time to open for “exhalation”. Then there are no losses from “reverse exhalation”.[...]
To understand the biochemical processes occurring in the body, the value of the respiratory coefficient is of great importance. Respiratory coefficient (RC) is the ratio of exhaled carbonic acid to consumed oxygen.[...]
To judge the influence of temperature on any process, they usually operate on the value of the temperature coefficient. The temperature coefficient (t>ω) of the respiration process depends on the type of plant and on temperature gradations. Thus, with an increase in temperature from 5 to 15 ° C, 0 ω can increase to 3, while an increase in temperature from 30 to 40 ° C increases the respiration intensity less significantly (ω about 1.5). The phase of plant development is of great importance. According to B., A. Rubin, at each phase of plant development, the most favorable temperatures for the respiration process are those against the background of which this phase usually takes place. The change in optimal temperatures during plant respiration depending on the phase of their development is due to the fact that in the process of ontogenesis they change respiratory exchange pathways. Meanwhile, different temperatures are most favorable for different enzyme systems. In this regard, it is interesting that in later phases of plant development, cases are observed when flavin dehydrogenases act as final oxidases, transferring hydrogen directly to air oxygen.[...]
All studied fish in captivity consume less oxygen than in natural conditions. A slight increase in the respiratory coefficient in fish kept in aquariums indicates a change in the qualitative side of metabolism towards a greater participation of carbohydrates and proteins in it. The author explains this by the worse oxygen regime of the aquarium compared to natural conditions; In addition, the fish in the aquarium are inactive.[...]
To reduce the emission of vapors of harmful substances, reflector disks are also used, installed under the mounting pipe of the breathing valve. With a high turnover rate of atmospheric tanks, the efficiency of reflector disks can reach 20-30%.[...]
Resaturation of the gas chamber can occur after filling if the gas space was not completely saturated with vapor. In this case, the breathing valve does not close after filling the container and additional exhalation immediately begins. This phenomenon occurs in tanks that have a high turnover ratio or are partially filled, not to the maximum filling height, as well as in tanks with slow saturation processes of the hydraulic fluid (tanks with pontoons and recessed ones). GP saturation is especially typical for tanks that are filled for the first time after cleaning and ventilation. This type of loss is sometimes called losses from saturation or saturation of the GP.[...]
For known u0 Acjcs can also be determined from graphs similar to those shown in Fig. 14. The methods for calculating losses provide similar graphs for typical RVS tanks, various types of breathing valves and their quantities. The value Ac/cs means the increase in concentration in the gas station during the total time of downtime (tp) and filling of the reservoir (te), i.e. t = t„ + t3; it is determined approximately from the graphs (see Fig. 3). When using formula (!9), it is necessary to keep in mind that with full saturation of the GP ccp/cs = 1 and that the time for complete saturation of the GP of ground-based reservoirs is limited to 2-4 days (depending on weather conditions and other conditions), and the graph on " Fig. 3 approximate. Therefore, having obtained the values ccp/cs>l from formula (19), which means the onset of complete saturation of the gas supply before the end of the downtime or the end of filling the tank, it is necessary to substitute ccp/cs = 1.[ . ..]
Let us evaluate the quantitative relationships between these two gas flows. Firstly, the ratio of the volume of carbon dioxide released to the volume of oxygen consumed (respiratory coefficient) for most wastewater and activated sludge is less than one. Secondly, the volumetric mass transfer coefficients for oxygen and carbon dioxide are close to each other. Thirdly, the phase equilibrium constant of carbon dioxide is almost 30 times less than that of oxygen. Fourthly, carbon dioxide is not only present in the sludge mixture in a dissolved state, but also enters into a chemical interaction with water.[...]
When comparing both types of respiration, the unequal ratio of oxygen absorption to carbon dioxide release is striking. The CO2/O2 ratio is designated as the respiratory coefficient KO.[...]
If during respiration organic substances with a relatively higher oxygen content than in carbohydrates are oxidized, for example organic acids - oxalic, tartaric and their salts, then the respiratory coefficient will be significantly greater than 1. It will also be greater than 1 in the case when part of the oxygen, used for microbial respiration, taken from carbohydrates; or during the respiration of those yeasts in which alcoholic fermentation occurs simultaneously with aerobic respiration. If, along with aerobic respiration, other processes occur in which additional oxygen is used, then the respiratory coefficient will be less than 1. It will also be less than 1 when substances with a relatively low oxygen content, such as proteins, hydrocarbons, etc., are oxidized during the respiration process. Consequently, , knowing the value of the respiratory coefficient, you can determine which substances are oxidized during respiration.[...]
The most general indicator of the rate of oxidation is the rate of respiration, which can be judged by the absorption of oxygen, the release of carbon dioxide and the oxidation of organic matter. Other indicators of respiratory metabolism: the value of the respiratory coefficient, the ratio of the glycolytic and pentose phosphate pathways of sugar breakdown, the activity of redox enzymes. The energy efficiency of respiration can be judged by the intensity of oxidative phosphorylation of mitochondria.[...]
The trends shown for Cox Orange apples regarding the influence of oxygen and carbon dioxide concentrations in the chamber air are valid for all other apple varieties, except for cases where the respiratory coefficient increases more strongly with decreasing temperature. [...]
The value of DC depends on other reasons. In some tissues, due to the difficult access of oxygen, along with aerobic respiration, anaerobic respiration occurs, which is not accompanied by oxygen absorption, which leads to an increase in the DC value. The value of the coefficient is also determined by the completeness of oxidation of the respiratory substrate. If, in addition to the final products, less oxidized compounds (organic acids) accumulate in the tissues, then DC[...]
Quantitative determinations of the dependence of gas exchange in fish on temperature have been carried out by many researchers. In most cases, the study of this issue was limited primarily to the quantitative side of respiration - the magnitude of the respiratory rhythm, the amount of oxygen consumption and then the calculation of temperature coefficients at different temperatures.[...]
To reduce losses due to evaporation and air pollution, gasoline tanks are equipped with a gas piping connecting the air spaces of the tanks in which products of the same brand are stored, and a common breathing valve is installed. The “large and small breathing” described above, ventilation of the gas space, also cause air pollution during the storage of petroleum products at agricultural facilities, since with a tank farm turnover ratio of 4-6, the fuel inventory turnover ratio is 10-20, which means a decrease in the ratio use of tanks 0.4-0.6. In order to prevent air pollution, oil depots are equipped with cleaning devices and gasoline-oil traps.[...]
The data obtained to date show that extreme temperatures cause inhibition of the physiological system, in particular the transport of gases in fish. At the same time, bradycardia develops, arrhythmia increases, oxygen consumption and its utilization rate decrease. Following these changes in the functioning of the cardiorespiratory apparatus, ventilation of the gills gradually ceases and, last of all, the myocardium ceases to function. Apparently, anoxia of the respiratory muscles and general oxygen deficiency are one of the reasons for the death of fish due to overheating. An increase in temperature leads to an acceleration of oxygen utilization and, as a consequence, to a drop in its tension in the dorsal aorta, which, in turn, serves as a signal for increased ventilation of the gills.[...]
Before using the model, its kinetic parameters should be checked. Validation of a pure oxygen system model for the treatment of domestic and industrial wastewater was done by Muller et al. (1) Model validation for domestic wastewater treatment used a respiratory coefficient R.C of 1.0, while for industrial wastewater it is 0.85 and even 0.60. Additional verification of chemical interactions was made quite recently when studying wastewater from a pulp and paper mill (Fig. 26.6). To evaluate the data obtained, the respiratory coefficient was assumed to be 0.90. there was not so much nitrogen, and a lower requirement for it for the growth of microorganisms was noted than traditionally observed in biological systems. [...]
To solve the question of the essence of the effect of temperature on the metabolism of fish, it is necessary to know not only the degree of increase or decrease in metabolism with a change in temperature, but also qualitative changes in the individual links that make up the metabolism. The qualitative side of metabolism can to some extent be characterized by such coefficients as respiratory and ammonia (the ratio of released ammonia as the final product of nitrogen metabolism to consumed oxygen) (Fig. 89).[...]
From the above equation (4) it follows that the ratio of the constants for 02 and CO2 is equal to 1.15, i.e., the use of the CO2 balance measurement technique would seem to allow observations to be made at slightly higher values of 2 and correspondingly higher flow velocities. But this apparent advantage disappears if we assume that the respiratory coefficient is less than 1. In addition, as Talling showed 32], the accuracy of determining CO2 in natural waters cannot be better than ± 1 µmol/l (0.044 mg/l), and oxygen - ±0.3 µmol/l (0.01 mg/l). Consequently, even if we take the respiratory coefficient equal to 1, the accuracy of the balance method, based on taking into account the balance of oxygen, turns out to be at least three times higher than when determining carbon dioxide.[...]
The morpho-physiological method was used in our studies with some additions. This made it possible to determine with sufficient accuracy (±3.5%) the amount of absorbed oxygen, released carbon dioxide and respiratory coefficient (RQ) on whole seedlings 10-12 days old and leaves of plants from field experiments. The principle of this technique is that plants placed in a closed vessel (specially designed gas pipette) with atmospheric air change the composition of the air as a result of respiration. Thus, knowing the volume of the vessel and determining the percentage composition of air at the beginning and end of the experiment, it is not difficult to calculate the amount of CO2 absorbed and released by plants. [...]
Various plant organs and tissues vary greatly in the conditions for supplying them with oxygen. In a leaf, oxygen flows freely to almost every cell. Juicy fruits, roots, tubers are very poorly ventilated; they are poorly permeable to gases, not only to oxygen, but also to carbon dioxide. Naturally, in these organs the respiration process shifts to the anaerobic side, and the respiratory coefficient increases. An increase in the respiratory coefficient and a shift in the respiration process to the anaerobic side are observed in meristematic tissues. Thus, different organs are characterized not only by different intensity, but also by unequal quality of the respiratory process.[...]
The question of substances used in the process of respiration has long been an issue for physiologists. Even in the works of I.P. Borodin, it was shown that the intensity of the respiration process is directly proportional to the content of carbohydrates in plant tissues. This gave reason to assume that carbohydrates are the main substance consumed during respiration. In clarifying this issue, determining the respiratory coefficient is of great importance. The respiratory coefficient is the volumetric or molar ratio of CO2 released during respiration to the CO2 absorbed during the same period of time. With normal access to oxygen, the value of the respiratory coefficient depends on the substrate of respiration. If carbohydrates are used in the breathing process, then the process proceeds according to the equation CeH) 2O5 + 6O2 = 6CO2 + 6H2O, in this case the respiratory coefficient is equal to one! = 1. However, if more oxidized compounds, such as organic acids, undergo decomposition during respiration, oxygen absorption decreases, and the respiratory coefficient becomes greater than unity. When more reduced compounds, such as fats or proteins, are oxidized during respiration, more oxygen is required and the respiratory coefficient becomes less than unity.[...]
So, the simplest process of aerobic respiration is represented in the following form. Molecular oxygen consumed during respiration is used mainly to bind hydrogen generated during the oxidation of the substrate. Hydrogen from the substrate is transferred to oxygen through a series of intermediate reactions that occur sequentially with the participation of enzymes and carriers. The so-called respiratory coefficient gives a certain idea of the nature of the breathing process. This is understood as the ratio of the volume of carbon dioxide released to the volume of oxygen absorbed during respiration (C02:02).[...]
The efficiency of the cardiorespiratory apparatus of fish, its reserve capabilities, and the lability of frequency and amplitude parameters depend on the species and ecological characteristics of the fish. When the temperature increased by the same amount (from 5 to 20°C), the respiratory rate of pike perch increased from 25 to 50 per minute, for pike from 46 to 75, and for ide from 63 to 112 per minute. Oxygen consumption increases in parallel with increasing frequency, but not depth of breathing. The largest number of respiratory movements to pump a unit volume of water is produced by the mobile ide, and the least by the less active oxyphilic pike perch, which positively correlates with the intensity of gas exchange in the studied species. According to the authors, the ratio of the maximum volume of ventilation and the corresponding oxygen utilization coefficient determines the maximum energy capabilities of the body. At rest, the highest intensity of gas exchange and volume of ventilation were in oxyphilic pike perch, and during functional load (motor activity, hypoxia) - in ide. At low temperatures, the increase in ventilation volume in ide in response to hypoxia was greater than at high temperatures, namely: 20-fold at 5°C and 8-fold at 20°C. In Orthologus thioglossy, under hypoxia (40% saturation), the volume of water pumped through the gills changes to a lesser extent: at 12°C it increases by 5 times, and at 28°C by 4.3 times.[...]
The indicators of carbohydrate metabolism during adaptive exogenous hypoxia, i.e., during mild to moderate oxygen deficiency in the environment, have been much less fully studied. However, the limited experimental data available show that in this case, there is an increased use of glycogen in the muscles, an increase in lactic acid and blood sugar. As would be expected, the level of water oxygen saturation at which these shifts occur varies across species. For example, in the lamprey, hyperglycemia was observed when the oxygen content decreased by only 20% of the initial level, and in 1 abeo karepvk the blood sugar concentration remained constantly low even at 40% oxygen saturation of the water, and only a further decrease in saturation led to a rapid increase in blood sugar levels. An increase in blood sugar and lactic acid has been noted during hypoxia in tench. A similar reaction to hypoxia was noted in channel catfish. In the first of these studies, at 50% saturation of water with oxygen, an increase in the content of lactic acid was detected in fish, which continued in the first hour of normoxia, i.e., after the fish returned to normal oxygen conditions. The restoration of biochemical parameters to normal occurred within 2-6 hours, and an increase in lactate content and respiratory coefficient from 0.8 to 2.0 indicated an increase in anaerobic glycolysis.
The respiratory quotient (RC) is the ratio of the volume of carbon dioxide released to the volume of oxygen absorbed over a certain time. If during the metabolic process only carbohydrates are oxidized in the body, then the respiratory coefficient will be equal to 1. This can be seen from the following formula:
Consequently, to form one molecule of CO 2 during the metabolism of carbohydrates, one molecule of O 2 is required. Since, according to the Avogadro-Gerard law, equal numbers of molecules at the same temperature and pressure occupy equal volumes. Therefore, the respiratory coefficient during the oxidation of carbohydrates will be equal to 1:
For fats it will be:
The oxidation of one molecule of fat requires 81.5 molecules of oxygen, and the oxidation of 1 gram molecule of fat requires 81.5 x 22.4 liters of oxygen, that is, 1825.6 liters of O 2, where 22.4 is the volume of one gram molecule in liters. A gram molecule of fat is equal to 890 g, then 1 liter of oxygen oxidizes 
487 g fat. 1 g of fat, upon complete oxidation, releases 38.945 kJ (9.3 kcal)*, and 0.487 gives 18.551 kJ. Therefore, the caloric equivalent of 1 liter of oxygen with a respiratory coefficient of 0.7 will be equal to 18.551 kJ. Under normal conditions, the respiratory coefficient lies between 1 and 0.7. With a DC of 0.7, fats are oxidized in the body and the caloric equivalent, or the caloric value of 1 liter of oxygen, is 18.551 kJ, and with a DC of 1 it is 21.135.
