The pathway by which oxygen from the outside enters the cell

It should include three steps, the first step is the exchange of gases between the lungs and the outside world, including the entry of oxygen from the outside into the lungs (in the alveoli) and the carbon dioxide in the lungs from the alveoli to the outside world; The second step is the exchange of gases between the lungs and the blood, including of course the oxygen in the alveoli into the blood and the carbon dioxide in the blood into the alveoli; The third step is the exchange of gas between the blood and the tissue cells, including the entry of oxygen from the blood into the tissue cells and the carbon dioxide in the tissue cells into the blood.

The first step is through the body's breathing movements, inhaling, allowing oxygen to enter the lungs (alveoli) through the respiratory tract (i.e., nose, pharynx, larynx, trachea, bronchi).

The second step is for oxygen entering the alveoli to diffuse into the bloodstream through alveolar epithelial cells (only a flat layer of epithelial cells) and a thin layer of capillary wall cells (the alveoli are surrounded by capillaries).

The third step is the diffusion of oxygen from the blood into the tissue cells.

This is how oxygen from the outside enters the cell.

Oxygen, water, CO2, and some fat-soluble substances (which can be understood by similar compatibility in chemistry because the cell membrane skeleton is made up of a phospholipid bilayer) all enter the cell through free diffusion.

And not all small molecules or ions enter the cell through free diffusion, such as potassium ions, sodium ions.

It is not that macromolecules must enter cells by active transport, such as endocytosis and glucose involved in the 2011 national college entrance examination questions to enter intestinal epithelial cells, which rely on "concentration difference potential energy".

Eventually in the mitochondria inside the cell.

Involved in respiration.

The exchange of gases in tissues takes place between the cells of the tissues and the blood, and when the blood flows through the cells of the tissues, the oxygen travels from the blood to the tissues because the oxygen content in the blood is greater than the oxygen concentration in the tissues.

Due to the same principle carbon dioxide.

It spreads and enters the bloodstream, so that the blood flows through the tissue cells and undergoes gas exchange, and the result is that the arterial blood becomes venous blood. Oxygen enters the human body and eventually reaches the mitochondria of tissue cells, where it participates in the oxidative decomposition of organic matter and provides energy for life activities.

Oxygen from the outside air is inhaled through breathing into the lungs and into the alveoli, which are lined with capillaries that contain red blood cells. In the alveoli, oxygen and carbon dioxide.

Oxygen enters the blood through the alveolar and capillary walls of the alveoli and capillaries, binds to red blood cells, and circulates throughout the body, while carbon dioxide is excreted from the body.

Oxygen-carrying red blood cells travel with the blood to the capillary groups and pass through the walls of the blood vessels into the interstitial fluid outside the tissue cells.

and then through the interstitial fluid into the histiocytes, which is also the site of carbon dioxide displacement in the histiocytes.

The process is: nasal throat, trachea, bronchi, alveolar cells, capillary wall, red blood cells, blood circulation.

Capillary network Capillary wall Interstitial fluid Histiocytes.

Through breathing exercises, air containing a large amount of oxygen from the outside is inhaled into the lungs, and the oxygen diffuses through the epithelial cells of the alveoli, then through the capillaries, into the bloodstream, and then into the red blood cells, where it binds to hemoglobin. When it reaches the tissues of the body, oxygen detaches from hemoglobin, crosses the red blood cell membrane, then passes through the capillary wall, enters the interstitial fluid, and then enters the tissue cells. a. In the process of excreting urea molecules from hepatocytes with urine, the structure that does not pass through is the renal vein, which is wrong; b. After the blood with this urea molecule flows through the capillary network of the lungs, it will not change from venous blood to arterial blood, B is wrong; c. After the urea molecule produced by hepatocytes enters the blood, the pathway of blood flow with the blood is:

Capillary in the liver Hepatic vein Inferior vena cava Right atrium Right ventricle Pulmonary artery Pulmonary capillaries Pulmonary veins Left atrium Left ventricle Aora Renal artery Affer arteriole Renal sac lumen Renal tubular Bladder urethra In vitro Therefore the urea molecule reaches the kidneys with the blood and must pass through the heart twice, c correct; d. When blood flows into the glomeruli, in addition to blood cells and macromolecular proteins, other substances such as water, inorganic salts, urea, and glucose will be filtered into the renal sac cavity to form protourine; When the original urine flows through the renal tubules, most of the water, part of the inorganic salts and all the glucose are reabsorbed back into the bloodstream, and the rest such as urea, some inorganic salts and water flow out of the renal tubules to form urine Therefore, when the urea molecule flows through the glomeruli with the blood, it is filtered into the renal sac to form the original urine, d is wrong Therefore, c

The three phases of aerobic respiration:

a. The first stage: in the cytoplasmic matrix, one molecule of glucose is decomposed into two molecules of pyruvate, and 4 [H] enzymes are removed at the same time; A small amount of energy is released during the process of hail lead decomposed by glucose, and part of this energy is used to synthesize ATP, producing a small amount of ATP. Reactive:

C6H12O6 enzyme 2 pyruvate + 4 [H]+ a small amount of energy.

b. The second stage: pyruvate enters the matrix of mitochondria, and the hydrogen in the two molecules of pyruvate and 6 water molecules are all removed, and a total of 20 [h] are removed, and the acetone is oxidized and decomposed into carbon dioxide; A small amount of energy is released in this process, part of which is used to synthesize ATP, producing a small amount of energy. Reactive:

2 pyruvate + 6H2O enzyme 20 [H] + 6CO2 + a small amount of energy.

c. The third stage: on the inner membrane of the chondria, a total of 24 [H] shedding in the first two stages are combined with 6 O2 produced by absorption from the outside or chloroplast photosynthesis to form water; In this process, a large amount of energy is released, and part of this energy is used to synthesize ATP, producing a large amount of energy. Reactive:

24[H]+6O2 enzyme 12H2O+ a lot of energy.

h] is a very simplified representation. This process is actually the conversion of oxidizing coenzyme (NAD+) to reducing coenzyme (NADH).

Aerobic respiration requires the participation of molecular oxygen, whereas anaerobic respiration does not require the participation of molecular oxygen.

The products of aerobic respiration are carbon dioxide and water, and the products of anaerobic respiration are alcohol or lactic acid.

Aerobic respiration releases more energy, while anaerobic respiration releases less energy than achievic respiration.

Aerobic Respiration - Formula:

The first stage of C6H12O6 enzyme cytoplasmic matrix = 2 pyruvate + 4 [H] + energy (2ATP).

Phase 2 pyruvate + 6H2O enzyme mitochondrial matrix = 6CO2 + 20 [H] + energy (2ATP).

The third stage 24[H]+6O2 enzyme inner mitochondrial membrane = 12H2O+ energy (34ATP).

The total reaction formula C6H12O6 + 6H2O + 6O2 enzyme 6CO2 + 12H2O + bulk energy (38ATP).

Oxygen, which cell is ultimately utilized, and where part of the cell is utilized.

Oxygen enters the bloodstream and is finally used in mitochondrial sites in the cell.

When the oxygen in the blood diffuses to the tissue cells, the organic matter in the cell is decomposed into carbon dioxide and water, and at the same time, the energy stored in the organic matter is released for the needs of human life activities, this process occurs in the mitochondria in the cell, which is the site of respiration.

oxygen is ultimately utilized in which cell and where part of the cell is utilized.

It reacts in the mitochondria of the cell and releases energy.

The way oxygen enters the tissue cells from the blood is by free diffusion.

Oxygen enters the tissue cells through 11 layers of membranes: alveolar wall monolayer cells: through 2 layers of cells that need to enter and exit; Capillary blood Zhengmo tube wall monolayer cells:

After 2 layers of cells that need to enter and exit; Oxygen is transported by red blood cells: into the 1st layer of red blood cells; No longer passing through the membrane during transportation; Arrival at destination out of red blood cells: 1 layer; Passing through the capillary wall monolayer of cells:

After 2 layers of cells that need to enter and exit; To enter the histiocytes: take 1 layer of Congqi. At this point, the answer to your question is out:

A total of 9 layers, note that this only says to enter the tissue cells, but if you ask to enter the tissue cells and participate in aerobic respiration, you must also add the mitochondrial membrane bilayer: 2 layers, a total of 11 layers

From the figure, we can see that the oxygen in the outside air finally reaches the tissue cells through the four processes of respiration The tissue cells use the oxygen obtained from the outside world by respiration to decompose organic matter, release energy for the use of cell life activities, and the carbon dioxide produced is also discharged into the outside air through the whole process of respiration

So the answer is: