If the erythrocyte is placed in saline. Erythrocytes in hypertonic solution
Article by professional biology tutor T. M. Kulakova
Blood is the intermediate internal environment of the body, is a fluid connective tissue. Blood is made up of plasma and formed elements.
Composition of the blood It is 60% plasma and 40% formed elements.
blood plasma consists of water, organic substances (proteins, glucose, leukocytes, vitamins, hormones), mineral salts and decay products.
Shaped elements are erythrocytes and platelets
blood plasma is the liquid part of the blood. It contains 90% water and 10% dry matter, mainly proteins and salts.
In the blood are metabolic products (urea, uric acid), which must be removed from the body. The concentration of salts in plasma is equal to the content of salts in blood cells. Blood plasma mainly contains 0.9% NaCl. The constancy of the salt composition ensures the normal structure and function of cells.
In USE tests, there are often questions about solutions: physiological (solution, NaCl salt concentration is 0.9%), hypertonic (NaCl salt concentration above 0.9%) and hypotonic (NaCl salt concentration below 0.9%).
For example, this question:
The introduction of large doses of drugs is accompanied by their dilution with saline (0.9% NaCl solution). Explain why.
Recall that if a cell comes into contact with a solution whose water potential is lower than that of its contents (i.e. hypertonic saline), then water will leave the cell due to osmosis through the membrane. Such cells (eg erythrocytes) shrink and settle to the bottom of the tube.
And if you put blood cells in a solution whose water potential is higher than the contents of the cell (i.e., the salt concentration in the solution is below 0.9% NaCl), red blood cells begin to swell because water rushes into the cells. In this case, the erythrocytes swell, and their membrane is torn.
Let's answer the question:
1. The concentration of salts in the blood plasma corresponds to the concentration of a physiological solution of 0.9% NaCl, which does not cause the death of blood cells;
2. The introduction of large doses of drugs without dilution will be accompanied by a change in the salt composition of the blood and cause cell death.
Remember that when writing an answer to a question, other wordings of the answer are allowed that do not distort its meaning.
For erudition: when the shell of erythrocytes is destroyed, hemoglobin enters the blood plasma, which turns red and becomes transparent. Such blood is called varnish blood.
100 ml of healthy human plasma contains about 93 g of water. The rest of the plasma consists of organic and inorganic substances. Plasma contains minerals, proteins (including enzymes), carbohydrates, fats, metabolic products, hormones, and vitamins.
Plasma minerals are represented by salts: chlorides, phosphates, carbonates and sulfates of sodium, potassium, calcium, magnesium. They can be both in the form of ions and in a non-ionized state.
Osmotic pressure of blood plasma
Even minor violations of the salt composition of the plasma can be detrimental to many tissues, and above all to the cells of the blood itself. The total concentration of mineral salts, proteins, glucose, urea and other substances dissolved in plasma creates osmotic pressure.
Osmosis phenomena occur wherever there are two solutions of different concentrations, separated by a semi-permeable membrane, through which the solvent (water) easily passes, but the solute molecules do not. Under these conditions, the solvent moves towards the solution with a higher concentration of the solute. Unilateral diffusion of liquid through a semi-permeable partition is called osmosis (Fig. 4). The force that causes the solvent to move through a semipermeable membrane is osmotic pressure. Using special methods, it was possible to establish that the osmotic pressure of human blood plasma is kept at a constant level and amounts to 7.6 atm (1 atm ≈ 105 N/m2).
Rice. 4. Osmotic pressure: 1 - pure solvent; 2 - salt solution; 3 - semi-permeable membrane dividing the vessel into two parts; the length of the arrows shows the speed of water movement through the membrane; A - osmosis, which began after filling both parts of the vessel with liquid; B - establishment of balance; H-pressure balancing osmosis
The osmotic pressure of plasma is mainly created by inorganic salts, since the concentration of sugar, proteins, urea and other organic substances dissolved in plasma is low.
Due to osmotic pressure, fluid penetrates through the cell membranes, which ensures the exchange of water between the blood and tissues.
The constancy of the osmotic pressure of the blood is important for the vital activity of the cells of the body. The membranes of many cells, including blood cells, are also semi-permeable. Therefore, when blood cells are placed in solutions with different salt concentrations, and, consequently, with different osmotic pressures, serious changes occur in blood cells due to osmotic forces.
A saline solution having the same osmotic pressure as blood plasma is called an isotonic solution. For humans, a 0.9% solution of common salt (NaCl) is isotonic, and for a frog, a 0.6% solution of the same salt.
Salt solution, the osmotic pressure of which is higher than the osmotic pressure of blood plasma, is called hypertonic; if the osmotic pressure of the solution is lower than in blood plasma, then such a solution is called hypotonic.
A hypertonic solution (usually a 10% saline solution) is used in the treatment of purulent wounds. If a bandage with a hypertonic solution is applied to the wound, then the fluid from the wound will come out onto the bandage, since the concentration of salts in it is higher than inside the wound. In this case, the liquid will carry along pus, microbes, dead tissue particles, and as a result, the wound will soon clear and heal.
Since the solvent always moves towards a solution with a higher osmotic pressure, when erythrocytes are immersed in a hypotonic solution, water, according to the laws of osmosis, begins to intensively penetrate into the cells. Erythrocytes swell, their membranes break, and the contents enter the solution. There is hemolysis. The blood, the erythrocytes of which have undergone hemolysis, becomes transparent, or, as is sometimes said, lacquered.
In human blood, hemolysis begins when erythrocytes are placed in a 0.44-0.48% NaCl solution, and in 0.28-0.32% NaCl solutions, almost all erythrocytes are destroyed. If red blood cells enter a hypertonic solution, they shrink. Verify this by doing experiments 4 and 5.
Note. Before carrying out laboratory work on the study of blood, it is necessary to master the technique of taking blood from a finger for analysis.
First, both the subject and the researcher thoroughly wash their hands with soap and water. Then the subject is wiped with alcohol on the ring (IV) finger of the left hand. The skin of the pulp of this finger is pierced with a sharp and pre-sterilized special feather needle. When pressing on the finger near the injection site, blood comes out.
The first drop of blood is removed with dry cotton, and the next one is used for research. It is necessary to ensure that the drop does not spread over the skin of the finger. Blood is drawn into a glass capillary by immersing its end into the base of the drop and placing the capillary in a horizontal position.
After taking blood, the finger is again wiped with a cotton swab moistened with alcohol, and then smeared with iodine.
Experience 4
Place a drop of isotonic (0.9 percent) NaCl solution on one end of the slide and a drop of hypotonic (0.3 percent) NaCl solution on the other. Prick the skin of the finger with a needle in the usual way and transfer a drop of blood to each drop of the solution with a glass rod. Mix the liquids, cover with coverslips and examine under a microscope (preferably at high magnification). Swelling of the majority of erythrocytes in a hypotonic solution is seen. Some of the red blood cells are destroyed. (Compare with erythrocytes in isotonic saline.)
Experience 5
Take another glass slide. Place a drop of 0.9% NaCl solution on one end of it, and a drop of hypertonic (10%) NaCl solution on the other. Add a drop of blood to each drop of solutions and, after mixing, examine them under a microscope. In a hypertonic solution, there is a decrease in the size of erythrocytes, their wrinkling, which is easily detected by their characteristic scalloped edge. In an isotonic solution, the edge of the erythrocytes is smooth.
Despite the fact that different amounts of water and mineral salts can enter the blood, the osmotic pressure of the blood is maintained at a constant level. This is achieved through the activity of the kidneys, sweat glands, through which water, salts and other metabolic products are removed from the body.
Saline
For the normal functioning of the body, it is important not only the quantitative content of salts in the blood plasma, which provides a certain osmotic pressure. The qualitative composition of these salts is also extremely important. An isotonic solution of sodium chloride is not able to maintain the work of the organ washed by it for a long time. The heart, for example, will stop if calcium salts are completely excluded from the fluid flowing through it, the same will happen with an excess of potassium salts.
Solutions that, in terms of their qualitative composition and salt concentration, correspond to the composition of plasma are called physiological solutions. They are different for different animals. In physiology, Ringer and Tyrode fluids are often used (Table 1).
Table 1. Composition of Ringer's and Tyrode's liquids (in g per 100 ml of water)
In addition to salts, glucose is often added to liquids for warm-blooded animals and the solution is saturated with oxygen. Such fluids are used to maintain the vital functions of organs isolated from the body, as well as blood substitutes for blood loss.
Blood reaction
The blood plasma has not only a constant osmotic pressure and a certain qualitative composition of salts, it maintains a constant reaction. In practice, the reaction of the medium is determined by the concentration of hydrogen ions. To characterize the reaction of the medium, the hydrogen indicator, denoted by pH, is used. (Hydrogen index is the logarithm of the concentration of hydrogen ions with the opposite sign.) For distilled water, the pH value is 7.07, an acidic environment is characterized by a pH of less than 7.07, and an alkaline one is more than 7.07. The pH of human blood at a body temperature of 37°C is 7.36. The active reaction of the blood is slightly alkaline. Even slight shifts in blood pH disrupt the body's activity and threaten its life. At the same time, in the process of vital activity, as a result of metabolism in tissues, significant amounts of acidic products are formed, for example, lactic acid during physical work. With increased breathing, when a significant amount of carbonic acid is removed from the blood, the blood can become alkaline. The body usually quickly copes with such deviations in the pH value. This function is carried out by buffer substances in the blood. These include hemoglobin, acid salts of carbonic acid (bicarbonates), salts of phosphoric acid (phosphates) and blood proteins.
The constancy of the reaction of the blood is maintained by the activity of the lungs, through which carbon dioxide is removed from the body; excess substances that have an acidic or alkaline reaction are excreted through the kidneys and sweat glands.
Plasma proteins
Of the organic substances in plasma, proteins are of the greatest importance. They ensure the distribution of water between the blood and tissue fluid, maintaining the water-salt balance in the body. Proteins are involved in the formation of protective immune bodies, bind and neutralize toxic substances that have entered the body. The plasma protein fibrinogen is the main factor in blood coagulation. Proteins give the blood the necessary viscosity, which is important for maintaining a constant level of blood pressure.
sohmet.ru
Practical work No. 3 Human erythrocytes in isotonic, hypotonic and hypertonic solutions
Take three numbered glass slides. Apply a drop of blood to each glass, then add a drop of physiological solution to the drop on the first glass, and 20% solution on the second glass with distilled water. Cover all drops with coverslips. Let the preparations stand for 10-15 minutes, then examine at high magnification of the microscope. In physiological saline, erythrocytes have the usual oval shape. In a hypotonic environment, red blood cells swell and then burst. This phenomenon is called hemolysis. In a hypertonic environment, erythrocytes begin to shrink, shrink, losing water.
Draw erythrocytes in isotonic, hypertonic and hypotonic solutions.
Execution of test tasks.
Samples of test tasks and situational tasks
chemical compounds that are part of the plasma membrane and, having hydrophobicity, serve as the main barrier to the penetration of water and hydrophilic compounds into the cell
polysaccharides
IF HUMAN ERYTHROCYTES ARE PLACED IN 0.5% NaCl SOLUTION, THEN WATER MOLECULES
will move predominantly into the cell
will move predominantly out of the cell
will not move.
will move in equal numbers in both directions: into the cell and out of the cell.
In medicine, gauze dressings moistened with a NaCl solution of a certain concentration are used to cleanse wounds from pus. SOLUTION IS USED FOR THIS PURPOSE
isotonic
hypertensive
hypotonic
neutral
a form of transport of substances across the outer plasma membrane of the cell, which requires the energy of ATP
pinocytosis
diffusion through the channel
facilitated diffusion
simple diffusion
Situational task
In medicine, gauze dressings moistened with a NaCl solution of a certain concentration are used to cleanse wounds from pus. What NaCl solution is used for this purpose and why?
Practice #3
The structure of eukaryotic cells. Cytoplasm and its components
The eukaryotic type of cellular organization with its high orderliness of life processes both in the cells of unicellular and multicellular organisms is due to the compartmentalization of the cell itself, i.e. dividing it into structures (components - the nucleus, plasmolemma and cytoplasm, with its inherent organelles and inclusions), differing in details of the structure, chemical composition and division of functions between them. However, the interaction of various structures with each other also takes place simultaneously.
Thus, the cell is characterized by integrity and discreteness, as one of the properties of living matter, in addition, it has the properties of specialization and integration in a multicellular organism.
The cell is the structural and functional unit of all life on our planet. Knowledge of the structure and functioning of cells is necessary for the study of anatomy, histology, physiology, microbiology and other disciplines.
to continue the formation of general biological concepts about the unity of all life on Earth and the specific features of representatives of various kingdoms, manifested at the cellular level;
to study the features of the organization of eukaryotic cells;
to study the structure and function of the organelles of the cytoplasm;
be able to find the main components of the cell under a light microscope.
To form professional competencies, a student must be able to:
distinguish eukaryotic cells and give their morphophysiological characteristics;
distinguish prokaryotic cells from eukaryotic; animal cells from plant cells;
find the main components of the cell (nucleus, cytoplasm, membrane) under a light microscope and on an electronogram;
to differentiate various organelles and cell inclusions on electron diffraction patterns.
To form professional competencies, a student must know:
features of the organization of eukaryotic cells;
structure and function of cytoplasmic organelles.
studfiles.net
Osmotic pressure of the blood
Osmotic pressure is the force that forces a solvent (for blood, it is water) to pass through a semipermeable membrane from a solution with a lower concentration to a more concentrated solution. Osmotic pressure determines the transport of water from the extracellular environment of the body to the cells and vice versa. It is caused by osmotically active substances soluble in the liquid part of the blood, which include ions, proteins, glucose, urea, etc.
Osmotic pressure is determined by the cryoscopic method, by determining the freezing point of blood. It is expressed in atmospheres (atm.) and millimeters of mercury (mm Hg). It is calculated that the osmotic pressure is 7.6 atm. or 7.6 x 760 = mm Hg. Art.
To characterize plasma as the internal environment of the body, the total concentration of all ions and molecules contained in it, or its osmotic concentration, is of particular importance. The physiological significance of the constancy of the osmotic concentration of the internal environment is to maintain the integrity of the cell membrane and ensure the transport of water and dissolved substances.
Osmotic concentration in modern biology is measured in osmoles (osm) or milliosmoles (mosm) - a thousandth of an osmol.
Osmol - the concentration of one mole of a non-electrolyte (for example, glucose, urea, etc.) dissolved in a liter of water.
The osmotic concentration of the non-electrolyte is less than the osmotic concentration of the electrolyte, since the electrolyte molecules dissociate into ions, as a result of which the concentration of kinetically active particles increases, which determine the osmotic concentration.
The osmotic pressure that a solution containing 1 osmol can develop is 22.4 atm. Therefore, osmotic pressure can be expressed in atmospheres or millimeters of mercury.
The osmotic plasma concentration is 285 - 310 mosm (on average 300 mosm or 0.3 osm), this is one of the most stringent parameters of the internal environment, its constancy is maintained by the osmoregulation system involving hormones and behavioral changes - the emergence of a feeling of thirst and the search for water.
The part of the total osmotic pressure due to proteins is called the colloid osmotic (oncotic) pressure of the blood plasma. Oncotic pressure is 25 - 30 mm Hg. Art. The main physiological role of oncotic pressure is to retain water in the internal environment.
An increase in the osmotic concentration of the internal environment leads to the transfer of water from the cells into the intercellular fluid and blood, the cells shrink and their functions are impaired. A decrease in osmotic concentration leads to the fact that water enters the cells, the cells swell, their membrane is destroyed, plasmolysis occurs. Destruction due to swelling of blood cells is called hemolysis. Hemolysis is the destruction of the shell of the most numerous blood cells - erythrocytes with the release of hemoglobin into plasma, which turns red and becomes transparent (lacquer blood). Hemolysis can be caused not only by a decrease in the osmotic concentration of blood. There are the following types of hemolysis:
1. Osmotic hemolysis - develops with a decrease in osmotic pressure. There is swelling, then destruction of red blood cells.
2. Chemical hemolysis - occurs under the influence of substances that destroy the protein-lipid membrane of erythrocytes (ether, chloroform, alcohol, benzene, bile acids, saponin, etc.).
3. Mechanical hemolysis - occurs with strong mechanical effects on the blood, for example, strong shaking of the ampoule with blood.
4. Thermal hemolysis - caused by freezing and thawing of blood.
5. Biological hemolysis - develops when incompatible blood is transfused, when bitten by some snakes, under the influence of immune hemolysins, etc.
In this section, we will dwell on the mechanism of osmotic hemolysis in more detail. To do this, we clarify such concepts as isotonic, hypotonic and hypertonic solutions. Isotonic solutions have a total ion concentration not exceeding 285-310 mmol. This may be 0.85% sodium chloride solution (often referred to as "physiological" solution, although this does not fully reflect the situation), 1.1% potassium chloride solution, 1.3% sodium bicarbonate solution, 5.5% glucose solution and etc. Hypotonic solutions have a lower concentration of ions - less than 285 mmol. Hypertensive, on the contrary, large - above 310 mmol. Erythrocytes, as is known, do not change their volume in an isotonic solution. In a hypertonic solution, they reduce it, and in a hypotonic solution, they increase their volume in proportion to the degree of hypotension, up to the rupture of an erythrocyte (hemolysis) (Fig. 2).
Rice. 2. The state of erythrocytes in a NaCl solution of various concentrations: in a hypotonic solution - osmotic hemolysis, in a hypertonic solution - plasmolysis.
The phenomenon of osmotic hemolysis of erythrocytes is used in clinical and scientific practice to determine the qualitative characteristics of erythrocytes (a method for determining the osmotic resistance of erythrocytes), the resistance of their membranes to destruction in a schipotonic solution.
Oncotic pressure
The part of the total osmotic pressure due to proteins is called the colloid osmotic (oncotic) pressure of the blood plasma. Oncotic pressure is 25 - 30 mm Hg. Art. This is 2% of the total osmotic pressure.
Oncotic pressure is more dependent on albumins (80% of oncotic pressure is created by albumins), which is associated with their relatively low molecular weight and a large number of molecules in plasma.
Oncotic pressure plays an important role in the regulation of water metabolism. The larger its value, the more water is retained in the vascular bed and the less it passes into the tissues and vice versa. With a decrease in the concentration of protein in the plasma, water ceases to be retained in the vascular bed and passes into the tissues, edema develops.
Blood pH regulation
pH is the concentration of hydrogen ions expressed as the negative logarithm of the molar concentration of hydrogen ions. For example, pH=1 means that the concentration is 101 mol/l; pH=7 - concentration is 107 mol/l, or 100 nmol. The concentration of hydrogen ions significantly affects the enzymatic activity, the physicochemical properties of biomolecules and supramolecular structures. Normal blood pH corresponds to 7.36 (in arterial blood - 7.4; in venous blood - 7.34). The extreme limits of blood pH fluctuations compatible with life are 7.0-7.7, or from 16 to 100 nmol / l.
In the process of metabolism in the body, a huge amount of "acidic products" is formed, which should lead to a shift in pH to the acid side. To a lesser extent, alkalis accumulate in the body during metabolism, which can reduce the hydrogen content and shift the pH of the medium to the alkaline side - alkalosis. However, the reaction of the blood under these conditions practically does not change, which is explained by the presence of buffer systems of the blood and neuro-reflex mechanisms of regulation.
megaobuchalka.ru
Tonicity is... What is Tonicity?
Tonicity (from τόνος - “tension”) is a measure of the osmotic pressure gradient, that is, the difference in the water potential of two solutions separated by a semipermeable membrane. This concept is usually applied to solutions surrounding cells. Osmotic pressure and tonicity can only be affected by solutions of substances that do not penetrate the membrane (electrolyte, protein, etc.). Solutions penetrating the membrane have the same concentration on both sides of the membrane and therefore do not change the tonicity.
Classification
There are three variants of tonicity: one solution in relation to another can be isotonic, hypertonic and hypotonic.
Isotonic solutions
Schematic representation of an erythrocyte in isotonic solutionIsotonia is the equality of osmotic pressure in liquid media and tissues of the body, which is ensured by maintaining osmotically equivalent concentrations of the substances contained in them. Isotonia is one of the most important physiological constants of the body, provided by the mechanisms of self-regulation. Isotonic solution - a solution having an osmotic pressure equal to intracellular. A cell immersed in an isotonic solution is in an equilibrium state - water molecules diffuse through the cell membrane in equal amounts inward and outward, without accumulating or being lost by the cell. The deviation of osmotic pressure from the normal physiological level entails a violation of the metabolic processes between the blood, tissue fluid and cells of the body. A strong deviation can disrupt the structure and integrity of cell membranes.
hypertonic solutions
A hypertonic solution is a solution that has a higher concentration of a substance in relation to the intracellular one. When a cell is immersed in a hypertonic solution, its dehydration occurs - intracellular water comes out, which leads to drying and wrinkling of the cell. Hypertonic solutions are used in osmotherapy for the treatment of intracerebral hemorrhage.
Hypotonic solutions
A hypotonic solution is a solution that has a lower osmotic pressure relative to another, that is, it has a lower concentration of a substance that does not penetrate the membrane. When a cell is immersed in a hypotonic solution, osmotic penetration of water into the cell occurs with the development of its overhydration - swelling, followed by cytolysis. Plant cells in this situation are not always damaged; when immersed in a hypotonic solution, the cell will increase turgor pressure, resuming its normal functioning.
Impact on cells
Epidermal cells of tradescantia are normal and in plasmolysis.
In animal cells, a hypertonic environment causes water to escape from the cell, causing cellular shrinkage (crenation). In plant cells, the effects of hypertonic solutions are more dramatic. The flexible cell membrane extends from the cell wall, but remains attached to it in the region of the plasmodesmata. Plasmolysis develops - cells acquire a "needle" appearance, plasmodesmata practically cease to function due to contraction.
Some organisms have specific mechanisms to overcome environmental hypertonicity. For example, fish living in a hypertonic saline solution maintain intracellular osmotic pressure by actively excreting excess salt they have drunk. This process is called osmoregulation.
In a hypotonic environment, animal cells swell to the point of rupture (cytolysis). To remove excess water in freshwater fish, the process of urination is constantly going on. Plant cells resist the effects of hypotonic solutions well due to a strong cell wall providing efficient osmolality or osmolality.
Some drugs for intramuscular use are preferably administered in the form of a slightly hypotonic solution, which allows them to be better absorbed by the tissues.
see also
- Osmosis
- Isotonic solutions
Classes
Exercise 1. The task includes 60 questions, each of which has 4 possible answers. For each question, choose only one answer that you think is the most complete and correct. Place a "+" sign next to the index of the selected answer. In case of correction, the "+" sign must be duplicated.
- Muscle tissue is made up of:
a) only mononuclear cells;
b) only multinuclear muscle fibers;
c) binuclear fibers tightly adjacent to each other;
d) mononuclear cells or multinuclear muscle fibers. + - Cells of striated striation, which make up fibers and interact with each other at the points of contact, form muscle tissue:
a) smooth;
b) cardiac; +
c) skeletal;
d) smooth and skeletal. - Tendons, through which muscles are connected to bones, are formed by connective tissue:
a) bone;
b) cartilaginous;
c) loose fibrous;
d) dense fibrous. + - The anterior horns of the gray matter of the spinal cord (“butterfly wings”) are formed by:
a) intercalary neurons;
b) bodies of sensitive neurons;
c) axons of sensitive neurons;
d) bodies of motor neurons. + - The anterior roots of the spinal cord are formed by the axons of neurons:
a) motor; +
b) sensitive;
c) only intercalary;
d) insertion and sensitive. - The centers of protective reflexes - coughing, sneezing, vomiting are located in:
a) cerebellum;
c) spinal cord;
c) intermediate part of the brain;
d) medulla oblongata. + - Erythrocytes placed in a physiological saline solution:
a) wrinkle;
b) swell and burst;
c) stick to each other
d) remain unchanged. + - Blood flows faster in vessels whose total lumen is:
a) the largest;
b) the smallest; +
c) average;
d) slightly above average. - The value of the pleural cavity lies in the fact that it:
a) protects the lungs from mechanical damage;
b) prevents overheating of the lungs;
c) participates in the removal of a number of metabolic products from the lungs;
d) reduces the friction of the lungs against the walls of the chest cavity, participates in the mechanism of lung stretching. + - The value of bile produced by the liver and entering the duodenum is that it:
a) breaks down hard-to-digest proteins;
b) breaks down hard-to-digest carbohydrates;
c) breaks down proteins, carbohydrates and fats;
d) increases the activity of enzymes secreted by the pancreas and intestinal glands, facilitates the breakdown of fats. + - Light sensitivity of sticks:
a) not developed;
b) the same as in cones;
c) higher than that of cones; +
d) lower than that of cones. - Jellyfish breed:
a) only sexually;
b) only asexually;
c) sexually and asexually;
d) some species only sexually, others - sexually and asexually. + - Why do children have new signs that are not characteristic of parents:
a) since all the gametes of the parents are of different sorts;
b) since during fertilization, gametes merge by chance;
c) in children, parental genes combine in new combinations; +
d) since the child receives one half of the genes from the father, and the other half from the mother. - The flowering of some plants only during the day is an example:
a) apical dominance;
b) positive phototropism; +
c) negative phototropism;
d) photoperiodism. - The filtration of blood in the kidneys occurs in:
a) pyramids;
b) pelvis;
c) capsules; +
d) the medulla. - When secondary urine is formed, the following return to the bloodstream:
a) water and glucose; +
b) water and salts;
c) water and proteins;
d) all of the above products. - For the first time among vertebrates, glands appear in amphibians:
a) salivary; +
b) sweat;
c) ovaries;
d) sebaceous. - The lactose molecule consists of residues:
a) glucose;
b) galactose;
c) fructose and galactose;
d) galactose and glucose.
- The statement is incorrect:
a) felines - a family of carnivores;
b) hedgehogs - a family of insectivorous order;
c) a hare is a genus of a detachment of rodents; +
d) the tiger is a species of the genus Panthera.
45. Protein synthesis does NOT require:
a) ribosomes;
b) t-RNA;
c) endoplasmic reticulum; +
d) amino acids.
46. The following statement is true for enzymes:
a) enzymes lose some or all of their normal activity if their tertiary structure is destroyed; +
b) enzymes provide the energy needed to stimulate the reaction;
c) enzyme activity does not depend on temperature and pH;
d) enzymes act only once and then are destroyed.
47. The greatest release of energy occurs in the process:
a) photolysis;
b) glycolysis;
c) Krebs cycle; +
d) fermentation.
48. For the Golgi complex, as a cell organoid, the following is most characteristic:
a) increasing the concentration and compaction of intracellular secretion products intended for release from the cell; +
b) participation in cellular respiration;
c) the implementation of photosynthesis;
d) participation in protein synthesis.
49. Cellular organelles that transform energy:
a) chromoplasts and leukoplasts;
b) mitochondria and leukoplasts;
c) mitochondria and chloroplasts; +
d) mitochondria and chromoplasts.
50. The number of chromosomes in tomato cells is 24. Meiosis occurs in a tomato cell. Three of the resulting cells degenerate. The last cell immediately divides by mitosis three times. As a result, in the resulting cells, you can find:
a) 4 nuclei with 12 chromosomes in each;
b) 4 nuclei with 24 chromosomes in each;
c) 8 nuclei with 12 chromosomes in each; +
d) 8 nuclei with 24 chromosomes in each.
51. Arthropod eyes:
a) all are complex;
b) complex only in insects;
c) complex only in crustaceans and insects; +
d) complex in many crustaceans and arachnids.
52. The male gametophyte in the reproduction cycle of pine is formed after:
a) 2 divisions;
b) 4 divisions; +
c) 8 divisions;
d) 16 divisions.
53. The final bud of lime on the shoot is:
a) apical;
b) lateral; +
c) may be subordinate;
d) sleeping.
54. The signal sequence of amino acids necessary for the transport of proteins into chloroplasts is located:
a) at the N-terminus; +
b) at the C-terminus;
c) in the middle of the chain;
d) in different proteins in different ways.
55. Centrioles double in:
a) G 1 -phase;
b) S-phase; +
c) G 2 -phase;
d) mitosis.
56. Of the following bonds, the least rich in energy:
a) the connection of the first phosphate with ribose in ATP; +
b) the bond of an amino acid with tRNA in aminoacyl-tRNA;
c) connection of phosphate with creatine in creatine phosphate;
d) the bond of acetyl with CoA in acetyl-CoA.
57. The phenomenon of heterosis is usually observed when:
a) inbreeding;
b) distant hybridization; +
c) creation of genetically pure lines;
d) self-pollination.
Task 2. The task includes 25 questions, with several answers (from 0 to 5). Place "+" signs next to the indexes of the selected answers. In case of corrections, the "+" sign must be duplicated.
- Furrows and gyrus are characteristic of:
a) diencephalon;
b) medulla oblongata;
c) cerebral hemispheres; +
d) cerebellum; +
e) midbrain. - In the human body, proteins can be directly converted into:
a) nucleic acids;
b) starch;
c) fats; +
d) carbohydrates; +
e) carbon dioxide and water. - The middle ear contains:
a) hammer; +
b) auditory (Eustachian) tube; +
c) semicircular canals;
d) external auditory meatus;
d) stirrup. + - Conditioned reflexes are:
a) species;
b) individual; +
c) permanent;
d) both permanent and temporary; +
e) hereditary.
5. The centers of origin of certain cultivated plants correspond to specific land regions of the Earth. This is because these places:
a) were the most optimal for their growth and development;
b) were not subject to serious natural disasters, which contributed to their preservation;
c) geochemical anomalies with the presence of certain mutagenic factors;
d) are free from specific pests and diseases;
e) were the centers of the most ancient civilizations, where the primary selection and reproduction of the most productive varieties of plants took place. +
6. One population of animals is characterized by:
a) free crossing of individuals; +
b) the possibility of meeting individuals of different sexes; +
c) similarity in genotype;
d) similar living conditions; +
e) balanced polymorphism. +
7. The evolution of organisms leads to:
a) natural selection
b) variety of species; +
c) adaptation to the conditions of existence; +
d) mandatory promotion of the organization;
e) the occurrence of mutations.
8. The surface complex of the cell includes:
a) plasmalemma; +
b) glycocalyx; +
c) the cortical layer of the cytoplasm; +
d) matrix;
e) cytosol.
9. Lipids that make up the cell membranes of Escherichia coli:
a) cholesterol;
b) phosphatidylethanolamine; +
c) cardiolipin; +
d) phosphatidylcholine;
e) sphingomyelin.
- Adventitious buds can form during cell division:
a) pericycle; +
b) cambium; +
c) sclerenchyma;
d) parenchyma; +
e) wound meristem. + - Adventitious roots can form during cell division:
a) traffic jams;
b) crusts;
c) phellogen; +
d) phelloderms; +
e) core rays. + - Substances synthesized from cholesterol:
a) bile acids; +
b) hyaluronic acid;
c) hydrocortisone; +
d) cholecystokinin;
e) estrone. + - Deoxynucleotide triphosphates are required for the process:
a) replication; +
b) transcription;
c) translation;
d) dark repair; +
e) photoreactivation. - The process leading to the transfer of genetic material from one cell to another:
a) transition
b) transversion;
c) translocation;
d) transduction; +
e) transformation. + - Oxygen scavenging organelles:
a) the core;
b) mitochondria; +
c) peroxisomes; +
d) Golgi apparatus;
e) endoplasmic reticulum. + - The inorganic basis of the skeleton of various living organisms can be:
a) CaCO 3 ; +
b) SrSO 4 ; +
c) SiO 2 ; +
d) NaCl;
e) Al 2 O 3. - Polysaccharide nature have:
a) glucose;
b) cellulose; +
c) hemicellulose; +
d) pectin; +
e) lignin. - Proteins containing heme:
a) myoglobin; +
b) FeS, mitochondrial proteins;
c) cytochromes; +
d) DNA polymerase;
e) myeloperoxidase. + - Which of the factors of evolution were first proposed by Ch. Darwin:
a) natural selection; +
b) genetic drift;
c) population waves;
d) isolation;
e) struggle for existence. + - Which of the named signs that have arisen in the course of evolution are examples of idioadaptations:
a) warm-bloodedness;
b) hairline of mammals; +
c) the external skeleton of invertebrates; +
d) external gills of the tadpole;
e) horny beak in birds. + - Which of the following breeding methods appeared in the 20th century:
a) interspecific hybridization;
b) artificial selection;
c) polyploidy; +
d) artificial mutagenesis; +
e) cell hybridization. +
22. Anemophilous plants include:
a) rye, oats; +
b) hazel, dandelion;
c) aspen, linden;
d) nettle, hemp; +
e) birch, alder. +
23. All cartilaginous fish have:
a) arterial cone; +
b) swim bladder;
c) spiral valve in the intestine; +
d) five gill slits;
e) internal fertilization. +
24. Representatives of marsupials live:
a) in Australia +
b) in Africa;
c) in Asia;
d) in North America; +
d) in South America. +
25. The following features are characteristic of amphibians:
a) have only pulmonary respiration;
b) have a bladder;
c) larvae live in water, and adults live on land; +
d) molting is characteristic of adults;
e) there is no chest. +
Task 3. Task for determining the correctness of judgments (Put a "+" sign next to the numbers of correct judgments). (25 judgments)
1. Epithelial tissues are divided into two groups: integumentary and glandular. +
2. In the pancreas, some cells produce digestive enzymes, while others produce hormones that affect carbohydrate metabolism in the body.
3. Physiological, they call a solution of sodium chloride 9% concentration. +
4. During prolonged fasting, with a decrease in blood glucose levels, glycogen disaccharide, which is present in the liver, is cleaved.
5. Ammonia, which is formed during the oxidation of proteins, is converted in the liver into a less toxic substance, urea. +
6. All ferns need water for fertilization. +
7. Under the action of bacteria, milk turns into kefir. +
8. During the dormant period, the vital processes of the seeds stop.
9. Bryophytes are a dead end branch of evolution. +
10. In the main substance of the cytoplasm of plants, polysaccharides predominate. +
11. Living organisms contain almost all the elements of the periodic table. +
12. Pea antennae and cucumber antennae are similar organs. +
13. The disappearance of the tail in frog tadpoles occurs due to the fact that dying cells are digested by lysosomes. +
14. Each natural population is always homogeneous in terms of the genotypes of individuals.
15. All biocenoses necessarily include autotrophic plants.
16. The first terrestrial higher plants were rhinophytes. +
17. All flagellates are characterized by the presence of a green pigment - chlorophyll.
18. In protozoa, each cell is an independent organism. +
19. Infusoria shoe belongs to the type Protozoa.
20. Scallops move in a jet way. +
21. Chromosomes are the leading components of the cell in the regulation of all metabolic processes. +
22. Algae spores can be formed by mitosis. +
23. In all higher plants, the sexual process is oogamous. +
24. Fern spores meiotically form an outgrowth, the cells of which have a haploid set of chromosomes.
25. Ribosomes are formed by self-assembly. +
27. 10 - 11 class
28. Task 1:
29. 1-d, 2-b, 3-d, 4-d, 5-a, 6-d, 7-d, 8-b, 9-d, 10-d, 11-c, 12-d, 13-c, 14-b, 15-c, 16-a, 17-a, 18-d, 19-c, 20-d, 21-a, 22-d, 23-d, 24-b, 25- d, 26-d, 27-b, 28-c, 29-d, 30-d, 31-c, 32-a, 33-b, 34-b, 35-b, 36-a, 37-c, 38–b, 39–c, 40–b, 41–b, 42–d, 43–c, 44–b, 45–c, 46–a, 47–c, 48–a, 49–c, 50– c, 51–c, 52–b, 53–b, 54–a, 55–b, 56–a, 57–b, 58–c, 59–b, 60–b.
30. Task 2:
31. 1 – c, d; 2 – c, d; 3 - a, b, e; 4 – b, d; 5 - d; 6 – a, b, d, e; 7 – b, c; 8 – a, b, c; 9 – b, c; 10 – a, b, d, e; 11 – c, d, e; 12 - a, c, e; 13 – a, d; 14 - d, e; 15 – b, c, e; 16 – a, b, c; 17 – b, c, d; 18 - a, c, e; 19 - a, e; 20 – b, c, e; 21 – c, d, e; 22 – a, d, e; 23 - a, c, e; 24 – a, d, e; 25 - c, d.
32. Task 3:
33. Correct judgments - 1, 3, 5, 6, 7, 9, 10, 11, 12, 13, 16, 18, 20, 21, 22, 23, 25.
constructor Create(aX, aY, aR, aColor, aShapeType)
method change_color (aColor)
method Resize (aR)
method change_location(aX, aY)
method Change_shape_type (aShape_type)
End of description.
Parameter aType_of_figure will receive a value that specifies the drawing method to be attached to the object.
When using delegation, you must ensure that the method header matches the type of pointer used to store the address of the method.
container classes.Containers - they are specially organized objects used to store and manage objects of other classes. To implement containers, special container classes are developed. A container class usually includes a set of methods that allow you to perform certain operations on both a single object and a group of objects.
In the form of containers, as a rule, they implement complex data structures (various types of lists, dynamic arrays, etc.). The developer inherits the class from the element class, into which he adds the information fields he needs, and receives the required structure. If necessary, it can also inherit the class from the container class, adding its own methods to it (Fig. 1.30).
Rice. 1.30. Building classes based on
container class and element class
A container class usually includes methods for creating, adding, and removing elements. In addition, it must provide element-by-element processing (eg, searching, sorting). All methods are programmed for member class objects. Methods for adding and removing elements when performing operations often refer to special fields of the element class used to create the structure (for example, for a singly linked list - to the field that stores the address of the next element).
Methods that implement element-by-element processing must work with data fields defined in descendant classes of the element class.
Element-by-element processing of the implemented structure can be done in two ways. The first way - universal - is to use iterators the second - in the definition of a special method, which contains the address of the processing procedure in the parameter list.
In theory, an iterator should provide the ability to implement cyclic actions of the following form:
<очередной элемент>:=<первый элемент>
cycle-bye<очередной элемент>defined
<выполнить обработку>
<очередной элемент>:=<следующий элемент>
Therefore, it usually consists of three parts: a method that allows organizing data processing from the first element (obtaining the address of the first element of the structure); a method that organizes the transition to the next element, and a method that allows you to check the end of the data. In this case, access to the next portion of data is carried out through a special pointer to the current portion of data (a pointer to an object of the element class).
Example 1.12 Container class with an iterator (List class). Let's develop a container class List that implements a linear singly linked list of objects of the Element class, described as follows:
Class Element:
field Pointer_to_next
End of description.
The List class must include three methods that make up an iterator: method define_first, which should return a pointer to the first element, the method define_next, which should return a pointer to the next element, and the method End of list, which should return "yes" if the list is exhausted.
Class List
implementation
fields Pointer_to_first, Pointer_to_current
interface
method add_before_first(aItem)
method Delete_Last
method define_first
method define_next
method End of list
End of description.
Then element-by-element processing of the list will be programmed as follows:
element:= define_first
cycle-bye not end_of_list
Handle the element, possibly overriding its type
Element: = define _next
When using the second method of element-by-element processing of the implemented structure, the element processing procedure is passed in the parameter list. Such a procedure can be defined if the type of processing is known, for example, the procedure for deriving the values of the information fields of an object. The procedure must be called from a method for each data element. In languages with strong data typing, the procedure type must be declared in advance, and it is often impossible to foresee what additional parameters should be passed to the procedure. In such cases, the first method may be preferable.
Example 1.13 Container class with a procedure for processing all objects (List class). In this case, the List class will be described as follows:
Class List
implementation
fields Pointer_to_first, Pointer_to_current
interface
method add_before_first(aItem)
method Delete_Last
method Execute_for_all(aProcedure_processing)
End of description.
Accordingly, the type of processing procedure must be described in advance, taking into account the fact that it must receive the address of the processed element through parameters, for example:
processing_procedure (aItem)
The use of polymorphic objects when creating containers allows you to create fairly generic classes.
Parameterized classes.Parameterized class(or sample) is a class definition in which some of the used types of class components are defined through parameters. Thus, each the template defines a group of classes, which, despite the difference in types, are characterized by the same behavior. It is impossible to redefine a type during program execution: all type instantiation operations are performed by the compiler (more precisely, by the preprocessor).
Osmosis is the movement of water across a membrane towards a higher concentration of substances.
Fresh water
The concentration of substances in the cytoplasm of any cell is higher than in fresh water, so water constantly enters the cells that come into contact with fresh water.
- erythrocyte in hypotonic solution fills up with water and bursts.
- In freshwater protozoa, to remove excess water, there is contractile vacuole.
- The cell wall prevents the plant cell from bursting. The pressure exerted by a water-filled cell on the cell wall is called turgor.
salty water
AT hypertonic solution water leaves the erythrocyte and it shrinks. If a person drinks sea water, then the salt will enter the plasma of his blood, and the water will leave the cells into the blood (all cells will shrink). This salt will need to be excreted in urine, the amount of which will exceed the amount of sea water drunk.
Plants have plasmolysis(departure of the protoplast from the cell wall).
Isotonic solution
Saline is a 0.9% sodium chloride solution. The plasma of our blood has the same concentration, osmosis does not occur. In hospitals, on the basis of saline, a solution for a dropper is made.