What do plants need CO2 for? How to prove the need for CO2? The gas composition of the air and its effect on the animal organism

The art of breathing is to barely exhale carbon dioxide and lose it as little as possible. As an example, the reaction of plant biosynthesis is the absorption of carbon dioxide, the utilization of carbon and the release of oxygen, and it was at that time that there was a very lush vegetation on the planet. Carbon dioxide CO2 is constantly being formed in the cells of the body.

Breathing is an exchange of gases, on the one hand, between blood and external environment(external respiration), on the other hand, the exchange of gases between blood and tissue cells (internal or tissue respiration).

Why does a person need carbon dioxide?

Oxygen is involved in the metabolism. Therefore, the cessation of oxygen supply leads to the death of tissues and the body. The main part of the respiratory system of the human body is the lungs, which perform the main function of respiration - the exchange of oxygen and carbon dioxide between the body and the external environment. This exchange is possible due to a combination of ventilation, diffusion of gases through the alveolar-capillary membrane and pulmonary circulation.

How is carbon dioxide distributed in the Earth's atmosphere?

In the process of external respiration, oxygen from the external environment is delivered to the alveoli of the lungs. The process of external respiration begins with the upper respiratory tract, which cleanses, warms and moisturizes the inhaled air. Ventilation of the lungs depends on respiratory metabolism and respiratory rate. Oxygen diffusion is carried out through the acinus - a structural unit of the lung, which consists of the respiratory bronchiole and alveoli.

Organisms need oxygen to breathe. The lack of oxygen in the air affects the life of living organisms. If the amount of oxygen in the air decreases to 1/3 of it, then the person loses consciousness, and if it decreases to 1/4 of it, breathing stops and death occurs.

It is blown into blast furnaces to speed up the smelting of metals. Carbon dioxide is formed during combustion (firewood, peat, coal, oil). A lot of it is released into the air during breathing by organisms, including humans. Heavier than air, carbon dioxide in more is located in the lower layers of the atmosphere, accumulates in the depressions of the Earth (caves, mines, gorges).

Man makes extensive use of carbon dioxide to carbonate fruit and mineral water when bottled. Carbon dioxide, like oxygen, under strong compression and low temperature changes from a gaseous state to a liquid and solid state. Carbon dioxide in solid form is called dry ice. It is used in refrigeration chambers while preserving ice cream, meat and other products.

Carbon dioxide does not support combustion, is heavier than air, and therefore is used to extinguish fires. Why can't people and other living organisms live without oxygen? What is the reason for the constant presence of oxygen in the air? How is liquid oxygen obtained and where is it used?

Where are the bubbles (carbon dioxide) in the soda?

Air is a mixture of natural gases - nitrogen, oxygen, argon, carbon dioxide, water and hydrogen. It is the primary source of energy for all organisms and the key to healthy growth and long life. Thanks to the air, the process of metabolism and development takes place in organisms. The basic components required for plant growth and life are oxygen, carbon dioxide, water vapor and soil air. Oxygen is needed for breathing, and carbon dioxide for carbon nourishment.

This element is needed by the roots and leaves, and the stems of plants. Carbon dioxide enters the plant by introducing through its stomata into the leaf medium, entering the cells. The higher the concentration of carbon dioxide, the better plant life becomes. Air also plays a special role in the formation of mechanical tissues in terrestrial plants.

Age, gender, size and physical activity directly related to the consumed amount of air. The body of animals is very sensitive to a lack of oxygen. This leads to an accumulation of harmful toxic substances in organism. Oxygen is necessary to saturate the blood and tissues of a living being. Therefore, with a lack of this element in animals, respiration becomes more frequent, blood flow accelerates, oxidative processes in the body decrease, and the animal becomes restless.

Carbon dioxide is not to blame for global warming

Air is a vital factor for humans. It is carried by the blood throughout the body, saturating every organ and every cell of the body. It is in the air that the heat exchange of the human body with the environment takes place. The essence of this exchange is the convective return of heat and the evaporation of moisture from their human lungs. With the help of breathing, a person saturates the body with energy. The reason for this is human production and man-made activities.

An adult, being at rest, makes an average of 14 respiratory movements per minute, but the respiratory rate can undergo significant fluctuations (from 10 to 18 per minute). An adult takes 15-17 breaths per minute, and a newborn baby takes 1 breath per second. The usual calm exhalation is largely passive, while the internal intercostal muscles and some abdominal muscles are actively working.

Distinguish between upper and lower respiratory tract. The symbolic transition of the upper respiratory tract to the lower is carried out at the intersection of the digestive and respiratory systems in the upper part of the larynx. Inhalation and exhalation are carried out by changing the size of the chest with the help of the respiratory muscles. During one breath (at rest), 400-500 ml of air enters the lungs. This volume of air is called the tidal volume (TO). The same amount of air enters the atmosphere from the lungs during a calm exhalation.

After the maximum expiration in the lungs, air remains in the amount of about 1,500 ml, called the residual volume of the lungs. Breathing is one of the few bodily functions that can be controlled consciously and unconsciously. Types of breathing: deep and shallow, frequent and rare, upper, middle (chest) and lower (abdominal).

The lungs (Latin pulmo, ancient Greek πνεύμων) are located in the chest cavity, surrounded by the bones and muscles of the chest. Besides, respiratory system participates in such important functions as thermoregulation, voice formation, smell, humidification of the inhaled air.

When the temperature drops environment gas exchange in warm-blooded animals (especially in small ones) increases as a result of an increase in heat production. In humans, when working at moderate power, it increases after 3-6 minutes. after its beginning reaches a certain level and then it is held at this level throughout the entire time of work. Studies of changes in gas exchange during standard physical work are used in the physiology of labor and sports, in the clinic to assess the functional state of the systems involved in gas exchange.

What is the use of oxygen in industry? It turned out that carbon dioxide, up to a certain limit, promotes a more complete assimilation of oxygen by the body. Carbon dioxide also participates in the biosynthesis of animal protein, in this some scientists see possible reason the existence of giant animals and plants many millions of years ago.

All life on Earth exists due to solar heat and energy reaching the surface of our planet. All animals and humans have adapted to extract energy from synthesized plants organic matter... To use the energy of the Sun, contained in the molecules of organic substances, it must be released by oxidizing these substances. Most often, air oxygen is used as an oxidizing agent, since it makes up almost a quarter of the volume of the surrounding atmosphere.

Single-celled protozoa, coelenterates, free-living flat and round worms breathe whole body surface. Special bodies breathing - cirrus gills appear in marine annelids and in aquatic arthropods. The respiratory organs of arthropods are trachea, gills, leaf-shaped lungs located in the recesses of the body integument. The respiratory system of the lancelet is presented gill slits penetrating the wall of the anterior intestine - the pharynx. In fish, under the gill covers are located gills, abundantly penetrated by the smallest blood vessels. In terrestrial vertebrates, the respiratory organs are lungs... The evolution of respiration in vertebrates followed the path of increasing the area of ​​the pulmonary partitions involved in gas exchange, improving the transport systems for delivering oxygen to the cells located inside the body, and developing systems that provide ventilation of the respiratory organs.

The structure and function of the respiratory system

A necessary condition for the vital activity of an organism is a constant gas exchange between the organism and the environment. The organs through which the inhaled and exhaled air circulate are combined into a breathing apparatus. The respiratory system is formed nasal cavity, pharynx, larynx, trachea, bronchi and lungs. Most of them are airways and serve to carry air into the lungs. In the lungs, gas exchange processes take place. When breathing, the body receives oxygen from the air, which is carried by the blood throughout the body. Oxygen participates in complex oxidative processes of organic substances, in which the energy necessary for the body is released. The end products of decay - carbon dioxide and partially water - are excreted from the body into the environment through the respiratory system.

Respiratory system functions

• Providing body cells with oxygen O 2.
• Removal from the body of carbon dioxide CO 2, as well as some end products metabolism (water vapor, ammonia, hydrogen sulfide).

Nasal cavity

Airways start with nasal cavity, which connects with the environment through the nostrils. From the nostrils, air passes through the nasal passages, lined with mucous, ciliated and sensitive epithelium. The external nose consists of bone and cartilaginous formations and has the shape of an irregular pyramid, which changes depending on the characteristics of a person's structure. The skeleton of the external nose includes the nasal bones and the nasal part of the frontal bone. The cartilaginous skeleton is an extension of the bone skeleton and consists of hyaline cartilage of various shapes... The nasal cavity has a lower, upper and two side walls... The lower wall is formed by the hard palate, the upper wall is formed by the ethmoid plate of the ethmoid bone, the lateral wall is formed by the upper jaw, the lacrimal bone, the orbital plate of the ethmoid bone, the palatine bone and the sphenoid bone. The nasal septum is divided into the right and left parts. The septum of the nose is formed by a vomer perpendicular to the plate of the ethmoid bone and is supplemented in front by the quadrangular cartilage of the nasal septum.

On the side walls of the nasal cavity there are nasal conchas - three on each side, which increases the inner surface of the nose, with which the inhaled air comes into contact.

The nasal cavity is formed by two narrow and sinuous nasal passages... Here the air is warmed up, humidified and freed from dust particles and microbes. The membrane lining the nasal passages is made up of mucus-secreting cells and ciliated epithelial cells. By the movement of the cilia, mucus, together with dust and microbes, is directed from the nasal passages outward.

The inner surface of the nasal passages is richly supplied with blood vessels. Inhaled air enters the nasal cavity, is heated, humidified, cleaned of dust and partially rendered harmless. From the nasal cavity, it enters the nasopharynx. Then air from the nasal cavity enters the pharynx, and from it into the larynx.

Larynx

Larynx- one of the divisions of the airways. Air enters here from the nasal passages through the pharynx. In the wall of the larynx there are several cartilages: thyroid, arytenoid, etc. At the moment of swallowing food, the muscles of the neck raise the larynx, and the epiglottis cartilage descends and the larynx closes. Therefore, food only enters the esophagus and does not enter the trachea.

In the narrow part of the larynx are located vocal cords, in the middle between them is the glottis. As air passes through, the vocal cords vibrate to produce sound. The formation of sound occurs on exhalation during the movement of air controlled by a person. The formation of speech involves: the nasal cavity, lips, tongue, soft palate, facial muscles.

Trachea

The larynx goes into trachea(windpipe), which has the shape of a tube about 12 cm long, in the walls of which there are cartilaginous half rings that do not allow it to fall off. Its back wall is formed by a connective tissue membrane. The tracheal cavity, like the cavity of other airways, is lined with ciliated epithelium, which prevents dust and other foreign bodies from entering the lungs. The trachea occupies a middle position, behind it is adjacent to the esophagus, and on the sides of it are the neurovascular bundles. In front, the cervical trachea is covered by muscles, and at the top it is also covered by the thyroid gland. The thoracic trachea is covered in front by the handle of the sternum, the remains of the thymus gland and blood vessels. From the inside, the trachea is covered with a mucous membrane containing a large number of lymphoid tissue and mucous glands. When breathing, small dust particles adhere to the moist mucous membrane of the trachea, and the cilia of the ciliated epithelium move them back to the exit from the respiratory tract.

The lower end of the trachea is divided into two bronchi, which then branch many times, enter the right and left lungs, forming a "bronchial tree" in the lungs.

Bronchi

In the chest cavity, the trachea is divided into two bronchus- left and right. Each bronchus enters the lung and there it is divided into bronchi of a smaller diameter, which branch out into the smallest air tubes - bronchioles. The bronchioles, as a result of further branching, turn into extensions - alveolar passages, on the walls of which there are microscopic protrusions called pulmonary vesicles, or alveoli.

The walls of the alveoli are built of a special thin unilamellar epithelium and are densely braided with capillaries. The total thickness of the wall of the alveoli and the wall of the capillary is 0.004 mm. Gas exchange takes place through this thinnest wall: oxygen enters the blood from the alveoli, and carbon dioxide enters the blood. The lungs contain several hundred million alveoli. Their total surface in an adult is 60–150 m 2. due to this, a sufficient amount of oxygen enters the blood (up to 500 liters per day).

Lungs

Lungs occupy almost the entire cavity of the chest cavity and are elastic spongy organs. In the central part of the lung, the gate is located, which includes the bronchus, pulmonary artery, nerves, and the pulmonary veins exit. The right lung is divided by grooves into three lobes, the left into two. Outside, the lungs are covered with a thin connective tissue film - pulmonary pleura, which passes to the inner surface of the chest cavity wall and forms a wall pleura. Between these two films, there is a pleural slit filled with fluid that reduces friction during breathing.

On the lung, three surfaces are distinguished: the outer, or costal, medial, facing the other lung, and the lower, or diaphragmatic. In addition, in each lung, two edges are distinguished: anterior and lower, separating the diaphragmatic and medial surfaces from the costal ones. Behind the costal surface, without a sharp border, passes into the medial one. Front edge the left lung has a cardiac notch. On the medial surface of the lung, its gate is located. The gate of each lung includes the main bronchus, the pulmonary artery, which carries venous blood into the lung, and the nerves that innervate the lung. From the gates of each lung, two pulmonary veins exit, which carry arterial blood and lymphatic vessels to the heart.

The lungs have deep grooves dividing them into lobes - upper, middle and lower, and in the left two - upper and lower. The lungs are not the same size. The right lung is slightly larger than the left, while it is shorter and wider, which corresponds to the higher standing of the right dome of the diaphragm due to the right-sided location of the liver. Normal lung color in childhood pale pink, and in adults they acquire a dark gray color with a bluish tint - a consequence of the deposition of dust particles that enter with the air. The lung tissue is soft, delicate and porous.

Gas exchange of the lungs

In the complex process of gas exchange, three main phases are distinguished: external respiration, gas transport by blood, and internal, or tissue, respiration. External respiration unites all processes in the lung. It is carried out by a breathing apparatus, which includes rib cage with the muscles that set it in motion, the diaphragm and the lungs with the airways.

The air that enters the lungs during inhalation changes its composition. The air in the lungs gives up some of the oxygen and is enriched with carbon dioxide. The content of carbon dioxide in venous blood is higher than in the air in the alveoli. Therefore, carbon dioxide leaves the blood in the alveoli and its content is less than in the air. First, oxygen dissolves in the blood plasma, then binds to hemoglobin, and new portions of oxygen enter the plasma.

The transition of oxygen and carbon dioxide from one medium to another takes place due to diffusion from a higher concentration to a lower one. Although diffusion proceeds slowly, the surface of contact of blood with air in the lungs is so large that it fully ensures the necessary gas exchange. It has been calculated that complete gas exchange between blood and alveolar air can take place in a time that is three times shorter than the time that blood remains in the capillaries (i.e., the body has significant reserves of oxygen supply to tissues).

Venous blood, once in the lungs, gives off carbon dioxide, is enriched with oxygen and turns into arterial blood. In a large circle, this blood flows through the capillaries into all tissues and gives oxygen to the cells of the body, which constantly consume it. There is more carbon dioxide released by cells as a result of their vital activity than in the blood, and it diffuses from the tissues into the blood. Thus, arterial blood, having passed through the capillaries of the systemic circulation, becomes venous and the right half of the heart is sent to the lungs, here it is again saturated with oxygen and gives off carbon dioxide.

In the body, respiration is carried out using additional mechanisms. Liquid media that make up the blood (its plasma) have a low solubility of gases in them. Therefore, in order for a person to exist, he would need to have a heart 25 times more powerful, lungs 20 times more powerful, and in one minute pump more than 100 liters of liquid (and not five liters of blood). Nature has found a way to overcome this difficulty by adapting a special substance, hemoglobin, to carry oxygen. Thanks to hemoglobin, blood is able to bind oxygen 70 times, and carbon dioxide - 20 times more than the liquid part of blood - its plasma.

Alveolus- a thin-walled bubble with a diameter of 0.2 mm, filled with air. The wall of the alveoli is formed by one layer of flat epithelial cells, along the outer surface of which a network of capillaries branches. Thus, gas exchange occurs through a very thin septum formed by two layers of cells: the walls of the capillary and the walls of the alveoli.

Gas exchange in tissues (tissue respiration)

The exchange of gases in tissues is carried out in capillaries according to the same principle as in the lungs. Oxygen from tissue capillaries, where its concentration is high, passes into tissue fluid with a lower oxygen concentration. From the tissue fluid, it enters the cells and immediately enters into oxidation reactions, therefore, there is practically no free oxygen in the cells.

Carbon dioxide according to the same laws comes from cells, through tissue fluid, into capillaries. The emitted carbon dioxide promotes the dissociation of oxyhemoglobin and itself enters into a compound with hemoglobin, forming carboxyhemoglobin, is transported into the lungs and released into the atmosphere. In the venous blood flowing from the organs, carbon dioxide is both in a bound and in a dissolved state in the form of carbonic acid, which in the capillaries of the lungs easily decomposes into water and carbon dioxide. Carbonic acid can also combine with plasma salts to form bicarbonates.

In the lungs, where venous blood enters, oxygen again saturates the blood, and carbon dioxide from the zone of high concentration (pulmonary capillaries) goes into the zone of low concentration (alveoli). For normal gas exchange, the air in the lungs is constantly replaced, which is achieved by rhythmic attacks of inhalation and exhalation, due to the movements of the intercostal muscles and the diaphragm.

Oxygen transport in the body

The meaning of breathing.

Breath is a set of physiological processes that ensure gas exchange between the body and the external environment ( external respiration), and oxidative processes in cells, as a result of which energy is released ( internal breathing). The exchange of gases between blood and atmospheric air ( gas exchange) - carried out by the respiratory organs.

Nutrients are the source of energy in the body. The main process that releases the energy of these substances is the oxidation process. It is accompanied by the binding of oxygen and the formation of carbon dioxide. Given that the human body does not have oxygen reserves, a continuous supply of oxygen is vital. Cessation of oxygen access to the cells of the body leads to their death. On the other hand, carbon dioxide formed in the process of oxidation of substances must be removed from the body, since the accumulation of a significant amount of it is life-threatening. The absorption of oxygen from the air and the release of carbon dioxide is carried out through the respiratory system.

The biological significance of respiration is:

• providing the body with oxygen;
• removing carbon dioxide from the body;
• oxidation organic compounds BZHU with the release of energy necessary for a person to live;
• removal of end products of metabolism ( vapors of water, ammonia, hydrogen sulfide, etc.).

Goals:

• To study the material about the importance of air for living organisms, about the change in the composition of the air, the connection between the processes taking place in living organisms and the world around them.
• Develop the ability to work with handouts, observe, draw conclusions; contribute to the formation of communicative competencies.
• To form students' ecological culture, the foundations of the worldview, to instill the foundations healthy way life.

DURING THE CLASSES

I. Organizational moment(1 minute.)

II. Knowledge check(5-7 min.)

1. Perform verification work. Give a choice (1 of 3)

Complete one of three tasks.

A. Test.

Choose the correct answers.

1. Choose the correct statements characterizing the properties of air:

a. squeeze and elastic
b. they can't breathe
v. poor heat conduction

2. A device for performing underwater work is called:

a. caisson
b. barometer
v. pressure gauge

3. The gas supporting combustion and breathing is called:

a. carbonic
b. oxygen
v. nitrogen

4. Gas making up the largest part of the air:

a. nitrogen
b. oxygen
v. neon

5. The air shell of the Earth is called:

a. lithosphere
b. hydrosphere
v. atmosphere

6. Gas that protects all life from solar radiation:

a. nitrogen
b. ozone
v. oxygen.

Answers: 1 - a, b; 2 - a; 3 - b; 4 - a; 5 - c; 6 - b.

B. Choose the correct statements

1. Air is compressed and resilient.
2. You can't breathe air.
3. Air is a mixture of gases.
4. Nitrogen in the air is 21%.
5. Carbon monoxide is essential for breathing.
6. Ozone protects living organisms from radiation.

2. Fill in the diagram and diagram "Air composition"

Answers. Scheme: nitrogen / oxygen / carbon dioxide / inert gases / water vapor, dust, soot.

Diagram: 78%, 21%, 1%.

3. Mutual verification(Answers are written on the chalkboard.) Voice the answers.

Physical education

Please stand by your desks.
The one who wrote on "5" will raise his hands up.
The one who wrote in "4" will raise his hands to his shoulders.
The one who wrote in "3" stands with lowered hands.

III. Learning new material. 20-25 minutes

1. Problem : Is it possible to live and not breathe?
………………..

- Let's do a simple experiment. Hold your breath, note the start time of the experiment, and then the time when you breathed in again. Count how many seconds you could not breathe?

Choice:

1) work independently, by the hour;
2) work under the guidance of a teacher.

So, agree - not a lot! A person can live without food for several weeks, since the cells have a supply of nutrients. You can live several days without water - its supply in the body is enough for almost a week.

• Why do we have to breathe constantly, even when we sleep?
• Probably, the body consumes the air necessary for life, and its supply must be constantly replenished.
• Guess what the lesson will be about today?

2. Topic of the lesson: “The importance of air for living organisms. Change in air composition. Combustion. Breath".

- Guys, what are you talking about? already know? What would you wanted to know?(Subjective experience)

3. Purpose of today's lesson to find out what value air has for living organisms, how the composition of air changes during respiration, how the processes occurring in living organisms and their environment are connected.

4. Motivation

- Guys, why do we need to study these questions?
- Knowledge of these issues will help in the study of physics, chemistry, biology, ecology; will help maintain your health, the health of others; to treat the nature around us correctly.

5. Learning new material using handouts

A. Change in air composition

Is the inhaled air different from the exhaled air?
To check this, you can run an experience. Lime water is poured into two test tubes, which will change in the presence of carbon dioxide. The air we breathe also has it, but there is not much of it. The device is designed so that the inhaled air enters the test tube No. 1, and the exhaled air enters the test tube No. 2. The more carbon dioxide in the air, the more the color of lime water changes. A person breathes into a tube: inhale - exhale, inhale - exhale.
The liquid in test tube # 2 will turn white, and in test tube # 1 it will turn slightly cloudy.

Write the output: in the exhaled air of carbon dioxide became ... than it was in the inhaled.

Detection of carbon dioxide in exhaled air.

B. Significance of air for living organisms

1) The body uses up oxygen and produces carbon dioxide. Oxygen constantly enters the living organism, and carbon dioxide is removed from it. This exchange process gases called gas exchange... It occurs in every living organism.

2) If the body consists of one cell, then the cell absorbs oxygen directly from the environment. Amoeba, for example, gets it from water, and releases carbon dioxide from the body into the water.

In living organisms, consisting of one cell, gas exchange with the environment occurs through the cell surface.

3 ) It is much more difficult to provide oxygen to each cell an organism consisting of many different cells, most of which are not on the surface, but inside the body. We need "helpers" who will provide each cell with oxygen and remove carbon dioxide from it. Respiratory organs and blood are such assistants in animals and humans.
Through the respiratory organs, oxygen enters the body from the environment, and the blood carries it throughout the body, to every living cell. In the same way, but in the opposite direction, accumulated carbon dioxide is removed from each cell, and then from the whole organism.

4) Different animals adapt in different ways to get the oxygen they need for life. This is due to the fact that some animals receive oxygen dissolved in water, others from atmospheric air.

A fish takes oxygen from the water using gills. Through them, carbon dioxide is removed into the environment.
Swimming beetle lives in water, but breathes atmospheric air. For breathing, he exposes the end of the abdomen from the water and receives oxygen through the respiratory openings and releases carbon dioxide.
At the frog gas exchange occurs through moist skin and lungs.
Seal can stay under water for up to 15 minutes. When diving, significant changes occur in the respiratory and circulatory systems of the animal: the vessels narrow, and some are completely compressed. Only the most important organs for life are supplied with blood: the heart and brain. Oxygen is consumed sparingly, which allows the animal to stay under water for a long time.

5) How do plants breathe?

Each living cell of the root, leaf, stem breathes, receiving oxygen from the environment and emitting carbon dioxide. Root cells receive oxygen from the soil. In the leaves of most plants, gas exchange occurs through the stomata (cracks
between special cells), and at the stem - through the lenticels (small tubercles with holes in the bark). Air is in the space between cells - in the intercellular spaces.

So, all living organisms in one way or another receive oxygen for life. Why is it so necessary? (For the breath of each cell.)
But we have not clarified one very important question: where does the oxygen disappear? After all, it enters the body constantly. Probably, some changes take place with it and instead of oxygen, carbon dioxide appears inside each cell.
What's going on? Do we accidentally eat several times a day and breathe constantly? Is there some connection between the constant consumption of nutrients and the consumption of oxygen?

Scientists are also interested in this issue. Here's what they found out.

• Each cell receives nutrients(a and b), since every living cell must feed.
• From these substances a and b, the cell forms its substance AB for life.
• Oxygen is supplied to every cell.
• Oxygen acts on the substance AB, while energy is released from it.

a, b, AB - substances necessary for the vital activity of the cell (nutrients);
c, d - substances harmful to the cell (decay products);
O is the energy contained in various substances.

For billions of years, all living things absorb oxygen and release carbon dioxide into the environment. The plant itself needs oxygen to breathe. So what happens? One and the same plant both absorbs oxygen and releases it.
How is the supply of oxygen on Earth replenished?
What happens in plant leaves in the light?

Write down: organic matter is formed in plants. This releases oxygen into the environment.
The plant breathes day and night. More oxygen is produced than is spent on breathing.

C. Complete the assignment in writing

Complete the sentence.

1). Every living organism receives ... , but stands out. ... This gas exchange process is called ....
2) Entering each cell, oxygen is consumed to obtain the necessary energy. Therefore, while running, when energy is needed, people and animals breathe ... than at rest.
3) Oxygen acts on ... substances in the cell, as a result of which the body receives the necessary for life ....
4) The more energy is spent, the more the body needs ... and nutrients.
5) A person who leads an active lifestyle needs more ... substances and ....
6) Oxygen and nutrients for life all living organisms get from ... Wednesday.
7) Air, food and water pollution can kill ... .
8) Plants provide all living organisms ... and ... .

Self-test.

• Oxygen, carbon dioxide, gas exchange.
• More often.
• Organic matter, energy.
• Oxygen.
• Nutrients and oxygen.
• Environment.
• Living organisms.
• Nutrients and oxygen.

G. Additionally: Explain the drawing. Assign the numbers and letters, determine the time of day.

1 2 3

a. The plant absorbs oxygen, emits carbon dioxide, that is, breathes
b. The plant absorbs ... , highlights …, forming organic matter in the light for nutrition.
v. The plant absorbs oxygen, releases … , that is, breathes.

Answer: 1a in the afternoon; 2b absorbs carbon dioxide during the day, releases oxygen; 3c emits carbon dioxide at night.

IV. Anchoring(5 minutes.)

1. Discuss with your deskmates what you need to do to make you feel comfortable in the office.

2. Make a checklist “Actions to improve the environmental situation in the classroom”.

3. Select from the following:

1. Ventilate the classroom more often.
2. Avoid burning activities.
3. Start required amount plants.
4. Play chips more often.
5. Change nothing.
6. Your own version.

V. Homework(3 min.)

1. Solve one problem on choice.

• It is known that nitrogen dissolves in water worse than oxygen. What is the difference between air dissolved in water and atmospheric air?
• Calculate the volume of oxygen in a liter bottle.

2. Explain the phrase "We need it like air"

Vi. Reflection

In the lesson, I learned ...

Air is a mixture of natural gases - nitrogen, oxygen, argon, carbon dioxide, water and hydrogen. It is the primary source of energy for all organisms and the key to healthy growth and long life. Thanks to the air, the process of metabolism and development takes place in organisms.

Air in plant and animal life

Air plays a huge role in plant life. The basic components required for plant growth and life are oxygen, carbon dioxide, water vapor and soil air. Oxygen is needed for breathing, and carbon dioxide for carbon nourishment.

Oxygen is vital for all living things. Plants cannot germinate without oxygenation. This element is needed by the roots and leaves, and the stems of plants.

Carbon dioxide enters the plant by introducing through its stomata into the leaf medium, entering the cells. The higher the concentration of carbon dioxide, the better plant life becomes.

Air promotes exercise microbiological processes occurring in the soil. Thanks to these processes, elements necessary for the nutrition, growth and life of plants are formed in the soil - nitrogen, phosphorus, potassium and others.

Air also plays a special role in the formation of mechanical tissues in terrestrial plants. It serves as an environment for them, protecting them from exposure to ultraviolet rays.

Air movement is important for the favorable growth of plants. The horizontal movement of air dries up the plants. And the vertical one promotes the spread of fingers, seeds, and also regulates the thermal regime in various territories.

Animals, like plants, need air. Age, gender, size and physical activity are directly related to the amount of air consumed.

The body of animals is very sensitive to a lack of oxygen. Due to the reduced oxygen concentration in animals, the consumed proteins, fats and carbohydrates cease to be oxidized. This leads to the accumulation of harmful toxic substances in the body.

Oxygen is necessary to saturate the blood and tissues of a living being. Therefore, with a lack of this element in animals, respiration becomes more frequent, blood flow accelerates, oxidative processes in the body decrease, and the animal becomes restless. Prolonged lack of oxygen saturation causes: muscle fatigue, lack of pain factor, a decrease in body temperature and death.

Air in a person's life

Air is a vital factor for humans. It is carried by the blood throughout the body, saturating every organ and every cell of the body.

It is in the air that the heat exchange of the human body with the environment takes place. The essence of this exchange is the convective return of heat and the evaporation of moisture from their human lungs.

Air also performs a protective function for the body: it dilutes chemical pollutants to a safe concentration. This helps to reduce the risk of poisoning the body with chemicals.

With the help of breathing, a person saturates the body with energy. Atmospheric air is composed of many elements, but its composition can vary. The reason for this is human production and man-made activities.

During exhalation, a person returns a quarter less oxygen inhaled and a hundred times more carbon dioxide. A person needs to inhale 13-14 m3 of air daily. The oxygen content in the body of a healthy person practically does not change. But if this element is not enough, then failures occur in the body, the pulse quickens.

Carbon dioxide is also important for the body, but in certain quantities. An increase in gas concentration causes headache or tinnitus.

Oxygen helps rid the human body of carbon dioxide, in which poisons and toxins are accumulated. If a person rarely goes out into the fresh air, breathes superficially, or the air contains a low concentration of oxygen, human body suffers poisoning, leading to various diseases.

Environmental pollution of the atmosphere

There is in the world great amount substances that pollute the atmosphere. These substances are produced both by humans and by nature itself. Sources of air pollution are: thermal power plants and heating plants, motor transport, non-ferrous and ferrous metallurgy, chemical production and others.

Human activities contribute to the emission of ash, soot, dust. Mineral acids and organic solvents also enter the atmosphere.

Natural disasters also emit various substances into the atmosphere. Volcanic eruptions, dust storms and forest fires emit: dust, sulfur dioxide, nitrogen and carbon oxides.

Traditionally, it is believed that oxygen is necessary for the life of living organisms. Therefore, it was quite surprising to read the title of the article "CO2 is necessary for plants for ...". See below for the answer to this riddle.

and its properties

Carbon dioxide, carbonic anhydrite - these are all names for the same substance. This is the well-known carbon dioxide. Under normal conditions, this substance is in a gaseous state, while it is colorless and odorless. When the air temperature drops, carbon dioxide hardens and acquires White color... In this modification, it is called It is quite chemical active substance... Carbon dioxide reacts with metals, oxides and alkalis. It is able to form an unstable compound with blood hemoglobin, like oxygen. This is how gas exchange is carried out using the circulatory system. It is not a poisonous substance, but at a high concentration it is classified as a toxic gas.

In nature, it is formed as a result of the respiration of living organisms, decay and combustion. In its gaseous state, carbon dioxide dissolves in water. That is why it is possible to talk about CO2 supply systems in aquariums with plants and their necessity for the normal life of algae. Has carbon dioxide and industrial value. It is widely used in the food industry as a baking powder and preservative. In a liquefied state, it is filled with fire extinguishers and automatic fire extinguishing systems.

What is photosynthesis

First of all, CO2 is necessary for plants for the most important process of planetary importance - photosynthesis. In its course, the carbohydrate glucose is formed from a number of inorganic substances. Plants use it for nutrition, growth, development and other vital processes. In addition, another product of this reaction is oxygen - the main condition for the existence of all living things on the planet, since it is necessary for breathing. Gas exchange in a plant is possible due to the presence of special formations in the integumentary tissue of their leaves - stomata. Each of them has two wings. Under certain conditions, they close and open. Through them, both oxygen and carbon dioxide are supplied.

Conditions for photosynthesis

Photosynthesis occurs only in specialized structures the main and integumentary tissue of the leaf. They are called chloroplasts. Their internal contents are represented by the thylakoids of the gran and stroma, on which the chlorophyll pigment is located. It gives some parts of the plant green color... In choroplasts, photosynthesis occurs only under certain conditions. This is the presence of sunlight, water and carbon dioxide. And the result of this chemical reaction is the formation of organic matter glucose and oxygen gas. The first of them is the source of life of the plants themselves, the second is used by all the others for implementation and has planetary significance.

Carbon dioxide and plants

How to prove the need for CO2? Very simple. Since carbon dioxide is released in nature as a result of respiration, its lack in nature is not observed. However, there is not much of it in aquarium water due to the small species diversity of living organisms. Therefore, if you do not use special installations for supplying carbon dioxide, after a certain time its amount will not be enough for an intensive flow. After all, CO2 is necessary for plants in order to independently produce nutrients. A timely and consistent supply of carbon dioxide to the water will ensure that your aquarium is filled with lush and vibrant algae.

The gas plants need to breathe: the importance of oxygen

It turns out that as a result of their vital activity they do not absorb it. Then the question arises: how do they breathe, and in general do they have a process of oxidation and decomposition of organic substances? Of course, like all other living organisms, they use the same oxygen. It turns out that two practically opposite processes occur simultaneously in plants. This is photosynthesis and respiration. Each of them is necessary for the normal life of plants.

Photosynthesis and respiration: which is more important

The uniqueness of plants lies in the fact that they are the only living creatures that emit both oxygen and carbon dioxide almost simultaneously. But this does not mean at all that they are dangerous and should not be located in residential premises. The thing is that plants emit much more oxygen than carbon dioxide.

In order not to disturb this natural balance, it is necessary to comply with the conditions for the course of these processes. For example, if a room with indoor plants does not penetrate sunlight, photosynthesis does not occur. In this case, the formation of glucose is stopped. But the breathing process continues. Large amounts of carbon dioxide accumulate in the air. And in this case, the plants can become dangerous. In the end, both of these processes are vital. Plants breathe only at the expense of oxygen, and with the help of carbon dioxide they produce glucose and feed.

So, CO2 is necessary for plants to carry out the process of obtaining organic substances - photosynthesis, which has critical importance planetary scale.