There is a firmly established opinion that human endurance is associated with training the heart muscle, and that for this you need to perform low-intensity work for a long time.
In fact, it's not like that: endurance is inextricably linked to the mitochondria inside muscle fibers. Therefore, endurance training is nothing more than the development of the maximum number of mitochondria within each muscle fiber.
And because Since the maximum number of mitochondria is limited by the space inside the muscle fiber, the development of endurance is limited by the number of muscles that are present in a particular person.
Briefly speaking: The more mitochondria a person has within specific muscle groups, the more endurance those specific muscle groups have.
And the most important: there is no general endurance. There is only local endurance of specific muscle groups.
Mitochondria. What it is
Mitochondria are special organelles (structures) inside the cells of the human body that are responsible for producing energy for muscle contractions. They are sometimes called the energy stations of the cell.
In this case, the process of energy production inside mitochondria occurs in the presence of oxygen. Oxygen makes the process of obtaining energy inside mitochondria as efficient as possible when compared to the process of obtaining energy without oxygen.
The fuel for energy production can be completely different substances: fat, glycogen, glucose, lactate, hydrogen ions.
Mitochondria and endurance. How does this happen
During muscle contraction, a residual product always appears. This is usually lactic acid, a chemical compound made of lactate and hydrogen ions.
As hydrogen ions accumulate inside the muscle fiber (muscle cell), they begin to interfere with the process of producing energy to contract the muscle fiber. And as soon as the concentration of hydrogen ions reaches a critical level, muscle contraction stops. And this moment may indicate the maximum level of endurance of a particular muscle group.
Mitochondria have the ability to absorb hydrogen ions and process them internally.
This results in the following situation. If a large number of mitochondria are present inside the muscle fibers, then they are able to utilize a larger number of hydrogen ions. This means working a specific muscle longer without having to stop the effort.
Ideally, if there are enough mitochondria inside working muscle fibers to utilize the entire amount of hydrogen ions produced, then such a muscle fiber becomes almost tireless and is able to continue working as long as there is a sufficient amount of nutrients for muscle contraction.
Example.
Almost every one of us is capable of walking at a fast pace for a long time, but quite soon we are forced to stop running at a fast pace. Why does this happen?
When walking fast, the so-called oxidative and intermediate muscle fibers. Oxidative muscle fibers are characterized by the maximum possible number of mitochondria, roughly speaking, there are 100% mitochondria there.
In intermediate muscle fibers there are noticeably fewer mitochondria, let it be 50% of the maximum number. As a result, hydrogen ions gradually begin to accumulate inside the intermediate muscle fibers, which should lead to the cessation of muscle fiber contraction.
But this does not happen due to the fact that hydrogen ions penetrate into the oxidative muscle fibers, where mitochondria easily cope with their utilization.
As a result, we are able to continue moving as long as there is enough glycogen in the body, as well as fat reserves inside the working oxidative muscle fibers. Then we will be forced to take a rest to replenish our energy reserves.
In the case of fast running, in addition to the mentioned oxidative and intermediate muscle fibers, the so-called. glycolytic muscle fibers, in which there are almost no mitochondria. Therefore, glycolytic muscle fibers are able to work only for a short time, but extremely intensely. This is how your running speed increases.
Then the total number of hydrogen ions becomes such that the entire number of mitochondria present there is no longer able to utilize them. There is a refusal to perform work of the proposed intensity.
But what would happen if all muscle groups had only oxidative muscle fibers inside them?
In this case, the muscle group with oxidative fibers becomes tireless. Her endurance becomes equal to infinity (provided there is a sufficient amount of nutrients - fats and glycogen).
We draw the following conclusion: For endurance training, the development of mitochondria within working muscle fibers is of primary importance. It is thanks to mitochondria that the endurance of muscle groups is achieved.
There is no general body endurance, because endurance (the ability to perform work of the proposed intensity) is associated with the presence of mitochondria in working muscles. The more mitochondria there are, the more endurance the muscles can show.
- Mitochondria are tiny inclusions in cells that were originally thought to be inherited from bacteria. In most cells there are up to several thousand of them, which is from 15 to 50 percent of the cell volume. They are the source of more than 90 percent of your body's energy.
- Your mitochondria have a huge impact on health, especially cancer, so optimizing mitochondrial metabolism may be at the heart of effective cancer treatment
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From Dr. Mercola
Mitochondria: You May Not Know What They Are, But They Are vital for Your health. Rhonda Patrick, PhD, is a biomedical scientist who has studied the interactions between mitochondrial metabolism, abnormal metabolism, and cancer.
Part of her work involves identifying early biomarkers of disease. For example, DNA damage is an early biomarker of cancer. She then tries to determine which micronutrients help repair this DNA damage.
She also researched mitochondrial function and metabolism, which is something I've recently become interested in. If, after listening to this interview, you want to learn more about this, I recommend starting with Dr. Lee Know's book, Life - The Epic Story of Our Mitochondria.
Mitochondria have a profound impact on health, especially cancer, and I am beginning to believe that optimizing mitochondrial metabolism may lie at the heart of effective cancer treatment.
The importance of optimizing mitochondrial metabolism
Mitochondria are tiny organelles that we were originally thought to have inherited from bacteria. There are almost none in red blood cells and skin cells, but in germ cells there are 100,000 of them, but in most cells there are from one to 2,000. They are the main source of energy for your body.
In order for organs to function properly, they need energy, and this energy is produced by mitochondria.
Since mitochondrial function underlies everything that happens in the body, optimizing mitochondrial function, and preventing mitochondrial dysfunction by getting all the essential nutrients and precursors required by mitochondria, is extremely important for health and disease prevention.
Thus, one of the universal characteristics of cancer cells is a serious impairment of mitochondrial function, in which the number of functional mitochondria is radically reduced.
Dr. Otto Warburg was a physician with a degree in chemistry and a close friend of Albert Einstein. Most experts recognize Warburg as the greatest biochemist of the 20th century.
In 1931, he received the Nobel Prize for his discovery that cancer cells use glucose as a source of energy production. This was called the “Warburg effect” but, unfortunately, this phenomenon is still ignored by almost everyone.
I am convinced that a ketogenic diet, which radically improves mitochondrial health, can help most cancers, especially when combined with a glucose scavenger such as 3-bromopyruvate.
How mitochondria produce energy
To produce energy, mitochondria need oxygen from the air you breathe and fat and glucose from the food you eat.
These two processes - breathing and eating - are coupled to each other in a process called oxidative phosphorylation. It is used by mitochondria to produce energy in the form of ATP.
Mitochondria have a series of electron transport chains through which they transfer electrons from the reduced form of the food you eat to combine with oxygen from the air you breathe to ultimately form water.
This process drives protons across the mitochondrial membrane, recharging ATP (adenosine triphosphate) from ADP (adenosine diphosphate). ATP transports energy throughout the body
But this process produces byproducts such as reactive oxygen species (ROS), which damage cells and mitochondrial DNA, then transferring them to the DNA of the nucleus.
Thus, a compromise occurs. By producing energy, the body getting old due to the destructive aspects of ROS that arise in the process. The rate at which the body ages depends largely on how well the mitochondria function and the amount of damage that can be compensated for by optimizing diet.
The role of mitochondria in cancer
When cancer cells appear, reactive oxygen species produced as a byproduct of ATP production send a signal that triggers the process of cell suicide, also known as apoptosis.
Since cancer cells are formed every day, this is a good thing. By killing damaged cells, the body gets rid of them and replaces them with healthy ones.
Cancer cells, however, are resistant to this suicide protocol—they have built-in defenses against it, as explained by Dr. Warburg and subsequently by Thomas Seyfried, who has deeply researched cancer as a metabolic disease.
As Patrick explains:
“One of the mechanisms of action of chemotherapy drugs is the formation of reactive oxygen species. They create damage, and this is enough to push the cancer cell towards death.
I think the reason for this is that a cancer cell that is not using its mitochondria, that is, no longer producing reactive oxygen species, and suddenly you force it to use mitochondria, and you get a surge of reactive oxygen species (after all, that's what mitochondria do), and - boom, death, because the cancer cell is already ready for this death. She's ready to die."
Why is it good not to eat in the evening?
I've been a fan of intermittent fasting for quite some time now for a variety of reasons, longevity and health concerns of course, but also because it appears to provide powerful cancer prevention and treatment benefits. And the mechanism for this is related to the effect that fasting has on mitochondria.
As mentioned, a major side effect of the electron transfer that mitochondria engage in is that some leak out of the electron transport chain and react with oxygen to form superoxide free radicals.
Superoxide anion (the result of reducing oxygen by one electron), is a precursor to most reactive oxygen species and a mediator of oxidative chain reactions. Oxygen free radicals attack lipids in cell membranes, protein receptors, enzymes and DNA, which can kill mitochondria prematurely.
Some free radicals, in fact, are even beneficial, necessary for the body to regulate cellular functions, but problems arise with excessive formation of free radicals. Unfortunately, this is why the majority of the population develops most diseases, especially cancer. There are two ways to solve this problem:
- Increase antioxidants
- Reduce the production of mitochondrial free radicals
In my opinion, one of the most effective strategies for reducing mitochondrial free radicals is to limit the amount of fuel you put into your body. This is not at all controversial, as calorie restriction has consistently demonstrated many therapeutic benefits. This is one of the reasons intermittent fasting is effective because it limits the period of time in which food is consumed, which automatically reduces the amount of calories consumed.
This is especially effective if you don't eat a few hours before bed because this is your metabolically lowest state.
This may all seem overly complicated to non-experts, but one thing to understand is that since the body uses the fewest calories during sleep, you should avoid eating before bed, because excess fuel at this time will lead to the formation of excess amounts of free radicals that destroy tissue. accelerate aging and contribute to the occurrence of chronic diseases.
How else does fasting help healthy mitochondrial function?
Patrick also notes that part of the mechanism behind the effectiveness of fasting is that the body is forced to obtain energy from lipids and fat stores, which means that cells are forced to use their mitochondria.
Mitochondria are the only mechanism by which the body can create energy from fat. Thus, fasting helps activate mitochondria.
She also believes it plays a huge role in the mechanism by which intermittent fasting and the ketogenic diet kill cancer cells, and explains why some mitochondria-activating drugs can kill cancer cells. Again, this is because a surge of reactive oxygen species is produced, the damage from which decides the outcome of the matter, causing the death of cancer cells.
Nutrition of mitochondria
From a nutritional perspective, Patrick emphasizes the following nutrients and important co-factors necessary for the proper functioning of mitochondrial enzymes:
- Coenzyme Q10 or ubiquinol (reduced form)
- L-carnitine, which transports fatty acids into the mitochondria
- D-ribose, which is the raw material for ATP molecules
- Magnesium
- All B vitamins, including riboflavin, thiamine and B6
- Alpha Lipoic Acid (ALA)
As Patrick notes:
“I prefer to get as many micronutrients as possible from whole foods for a variety of reasons. Firstly, they form a complex with fibers, which facilitates their absorption.
In addition, in this case their correct ratio is ensured. You won't be able to get them in abundance. The ratio is exactly what you need. There are other components that are likely yet to be determined.
You have to be very vigilant in making sure you're eating a wide range of [foods] and getting the right micronutrients. I think taking a B complex supplement is helpful for this reason.
For this reason I accept them. Another reason is that as we age, we no longer absorb B vitamins as easily, mainly due to the increasing rigidity of cell membranes. This changes the way B vitamins are transported into the cell. They are water soluble, so they are not stored in fat. It is impossible to get poisoned by them. In extreme cases, you will urinate a little more. But I am sure that they are very useful."
Exercise can help keep mitochondria young
Exercise also promotes mitochondrial health because it gets your mitochondria working. As mentioned earlier, one of the side effects of increased mitochondrial activity is the creation of reactive oxygen species, which act as signaling molecules.
One of the functions they signal is the formation of more mitochondria. So when you exercise, the body responds by creating more mitochondria to meet increased energy demands.
Aging is inevitable. But your biological age can be very different from your chronological age, and mitochondria have a lot in common with biological aging. Patrick cites recent research that shows how people can age biologically Very at different paces.
The researchers measured more than a dozen different biomarkers, such as telomere length, DNA damage, LDL cholesterol, glucose metabolism and insulin sensitivity, at three points in people's lives: ages 22, 32 and 38.
“We found that someone aged 38 could biologically look 10 years younger or older, based on biological markers. Despite the same age, biological aging occurs at completely different rates.
Interestingly, when these people were photographed and their photographs were shown to passers-by and asked to guess the chronological age of the people depicted, people guessed the biological age, not the chronological age.”
So, regardless of your actual age, how old you look corresponds to your biological biomarkers, which are largely determined by your mitochondrial health. So while aging can't be avoided, you have a lot of control over how you age, and that's a lot of power. And one of the key factors is keeping mitochondria in good working order.
According to Patrick, “youth” is not so much chronological age, but how old you feel and how well your body works:
“I want to know how to optimize my mental performance and my athletic performance. I want to prolong my youth. I want to live to be 90. And when I do, I want to surf in San Diego the same way I did in my 20s. I wish I didn't fade away as quickly as some people. I like to delay this decline and prolong my youth as long as possible, so that I can enjoy life as much as possible.”
The structure and function of mitochondria is a rather complex issue. The presence of an organelle is characteristic of almost all nuclear organisms - both autotrophs (plants capable of photosynthesis) and heterotrophs, which are almost all animals, some plants and fungi.
The main purpose of mitochondria is the oxidation of organic substances and the subsequent use of the energy released as a result of this process. For this reason, organelles also have a second (unofficial) name - the energy stations of the cell. They are sometimes called "catabolism plastids".
What are mitochondria
The term is of Greek origin. Translated, this word means “thread” (mitos), “grain” (chondrion). Mitochondria are permanent organelles that are of great importance for the normal functioning of cells and make the existence of the entire organism possible.
“Stations” have a specific internal structure, which changes depending on the functional state of the mitochondria. Their shape can be of two types - oval or oblong. The latter often has a branching appearance. The number of organelles in one cell ranges from 150 to 1500.
A special case is germ cells. Sperm contain only one spiral organelle, while female gametes contain hundreds of thousands more mitochondria. In a cell, organelles are not fixed in one place, but can move throughout the cytoplasm and combine with each other. Their size is 0.5 microns, their length can reach 60 microns, while the minimum is 7 microns.
Determining the size of one “energy station” is not an easy task. The fact is that when examined under an electron microscope, only part of the organelle gets into the section. It happens that a spiral mitochondrion has several sections that can be mistaken for separate, independent structures.
Only a three-dimensional image will make it possible to find out the exact cellular structure and understand whether we are talking about 2-5 separate organelles or one mitochondria with a complex shape.
Structural features
The mitochondrial shell consists of two layers: outer and inner. The latter includes various outgrowths and folds, which have a leaf-like and tubular shape.
Each membrane has a special chemical composition, a certain amount of certain enzymes and a specific purpose. The outer shell is separated from the inner shell by an intermembrane space 10-20 nm thick.
The structure of the organelle looks very clearly in the figure with captions.
Mitochondria structure diagram
Looking at the structure diagram, we can make the following description. The viscous space inside the mitochondrion is called the matrix. Its composition creates a favorable environment for the necessary chemical processes to occur in it. It contains microscopic granules that promote reactions and biochemical processes (for example, they accumulate glycogen ions and other substances).
The matrix contains DNA, coenzymes, ribosomes, t-RNA, and inorganic ions. ATP synthase and cytochromes are located on the surface of the inner layer of the shell. Enzymes contribute to processes such as the Krebs cycle (TCA cycle), oxidative phosphorylation, etc.
Thus, the main task of the organelle is performed by both the matrix and the inner side of the shell.
Functions of mitochondria
The purpose of “energy stations” can be characterized by two main tasks:
- energy production: oxidative processes are carried out in them with the subsequent release of ATP molecules;
- storage of genetic information;
- participation in the synthesis of hormones, amino acids and other structures.
The process of oxidation and energy production takes place in several stages:
Schematic drawing of ATP synthesis
It is worth noting: As a result of the Krebs cycle (citric acid cycle), ATP molecules are not formed, the molecules are oxidized and carbon dioxide is released. This is an intermediate step between glycolysis and the electron transport chain.
Table “Functions and structure of mitochondria”
What determines the number of mitochondria in a cell?
The prevailing number of organelles accumulates near those areas of the cell where the need for energy resources arises. In particular, a large number of organelles gather in the area where myofibrils are located, which are part of the muscle cells that ensure their contraction.
In male germ cells, the structures are localized around the axis of the flagellum - it is assumed that the need for ATP is due to the constant movement of the gamete tail. The arrangement of mitochondria in protozoa, which use special cilia for movement, looks exactly the same - the organelles accumulate under the membrane at their base.
As for nerve cells, the localization of mitochondria is observed near the synapses through which signals from the nervous system are transmitted. In cells that synthesize proteins, organelles accumulate in zones of ergastoplasm - they supply the energy that powers this process.
Who discovered mitochondria
The cellular structure acquired its name in 1897-1898 thanks to K. Brand. Otto Wagburg was able to prove the connection between the processes of cellular respiration and mitochondria in 1920.
Conclusion
Mitochondria are the most important component of a living cell, acting as an energy station that produces ATP molecules, thereby ensuring cellular life processes.
The work of mitochondria is based on the oxidation of organic compounds, resulting in the generation of energy potential.
Mitochondria are the “powerhouses” of eukaryotes, producing energy for cellular activity. These generate energy by converting it into forms that can be used by the cell. Located in, mitochondria serve as the “base” for cellular respiration. - a process that generates energy for cell activity. Mitochondria are also involved in other cellular processes such as growth and.
Distinctive characteristics
Mitochondria have a characteristic oblong or oval shape and are covered with a double membrane. They are found both in and in. The number of mitochondria within a cell varies depending on the type and function of the cell. Some cells, such as mature red blood cells, do not contain mitochondria at all. The absence of mitochondria and other organelles leaves room for the millions of hemoglobin molecules needed to transport oxygen throughout the body. On the other hand, muscle cells can contain thousands of mitochondria, which generate the energy needed for muscle activity. Mitochondria are also abundant in fat cells and liver cells.
Mitochondrial DNA
Mitochondria have their own DNA (mtDNA) and can synthesize their own proteins. mtDNA encodes proteins involved in electron transfer and oxidative phosphorylation that occur during cellular respiration. Oxidative phosphorylation in the mitochondrial matrix generates energy in the form of ATP. Proteins synthesized from mtDNA are also encoded to produce RNA molecules that transmit RNA and ribosomal RNA.
Mitochondrial DNA differs from the DNA found in , in that it does not possess the DNA repair mechanisms that help prevent mutations in nuclear DNA. As a result, mtDNA has a much higher mutation rate than nuclear DNA. Exposure to reactive oxygen produced by oxidative phosphorylation also damages mtDNA.
The structure of mitochondria
Mitochondria are surrounded by double . Each of these membranes is a phospholipid bilayer with embedded proteins. The outer membrane is smooth, but the inner membrane has many folds. These folds are called cristae. They increase the “productivity” of cellular respiration by increasing the available surface area.
Double membranes divide the mitochondrion into two distinct parts: the intermembrane space and the mitochondrial matrix. The intermembrane space is the narrow part between two membranes, while the mitochondrial matrix is the part enclosed within the membranes.
The mitochondrial matrix contains mtDNA, ribosomes and enzymes. Some of the steps of cellular respiration, including the citric acid cycle and oxidative phosphorylation, occur in the matrix due to the high concentration of enzymes.
Mitochondria are semi-autonomous, as they are only partially dependent on the cell to replicate and grow. They have their own DNA, ribosomes, proteins and control over their synthesis. Like bacteria, mitochondria have circular DNA and replicate by a reproductive process called binary fission. Before replication, mitochondria fuse together in a process called fusion. This is necessary to maintain stability, since without it the mitochondria will shrink as they divide. Reduced mitochondria are not able to produce enough energy necessary for normal cell functioning.
A double-membrane organelle, the mitochondrion, is characteristic of eukaryotic cells. The functioning of the body as a whole depends on the functions of mitochondria.
Structure
Mitochondria consist of three interconnected components:
- outer membrane;
- inner membrane;
- matrix.
The outer smooth membrane consists of lipids, between which there are hydrophilic proteins that form tubules. Molecules pass through these tubules during the transport of substances.
The outer and inner membranes are located at a distance of 10-20 nm. The intermembrane space is filled with enzymes. Unlike lysosome enzymes involved in the breakdown of substances, enzymes in the intermembrane space transfer phosphoric acid residues to the substrate with the consumption of ATP (phosphorylation process).
The inner membrane is packed under the outer membrane in the form of numerous folds - cristae.
They are educated:
- lipids, permeable only to oxygen, carbon dioxide, water;
- enzymatic, transport proteins involved in oxidative processes and transport of substances.
Here, due to the respiratory chain, the second stage of cellular respiration occurs and the formation of 36 ATP molecules.
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Between the folds there is a semi-liquid substance - the matrix.
The matrix includes:
- enzymes (hundreds of different types);
- fatty acid;
- proteins (67% mitochondrial proteins);
- mitochondrial circular DNA;
- mitochondrial ribosomes.
The presence of ribosomes and DNA indicates some autonomy of the organelle.
Rice. 1. The structure of mitochondria.
Enzymatic matrix proteins are involved in the oxidation of pyruvate - pyruvic acid during cellular respiration.
Meaning
The main function of mitochondria in a cell is the synthesis of ATP, i.e. energy generation. As a result of cellular respiration (oxidation), 38 ATP molecules are formed. ATP synthesis occurs based on the oxidation of organic compounds (substrate) and phosphorylation of ADP. The substrate for mitochondria is fatty acids and pyruvate.
Rice. 2. Formation of pyruvate as a result of glycolysis.
A general description of the breathing process is presented in the table.
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Where does it happen? |
Substances |
Processes |
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Cytoplasm |
As a result of glycolysis, it decomposes into two molecules of pyruvic acid, which enter the matrix |
|
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An acetyl group is cleaved, which attaches to coenzyme A (CoA), forming acetyl-coenzyme-A (acetyl-CoA), and a molecule of carbon dioxide is released. Acetyl-CoA can also be formed from fatty acids in the absence of carbohydrate synthesis |
||
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Acetyl-CoA |
Enters the Krebs cycle or the citric acid cycle (tricarboxylic acid cycle). The cycle begins with the formation of citric acid. Next, as a result of seven reactions, two molecules of carbon dioxide are formed, NADH and FADH2 |
|
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NADH and FADH2 |
When oxidized, NADH decomposes into NAD +, two high-energy electrons (e –) and two H + protons. The electrons are transferred to the respiratory chain, containing three enzyme complexes, on the inner membrane. The passage of an electron through the complexes is accompanied by the release of energy. At the same time, protons are released into the intermembrane space. Free protons tend to return to the matrix, which creates an electrical potential. As the voltage increases, H+ rush inward through ATP synthase, a special protein. Proton energy is used to phosphorylate ADP and synthesize ATP. H+ combines with oxygen to form water. |
Rice. 3. The process of cellular respiration.
Mitochondria are organelles on which the functioning of the whole organism depends. Signs of mitochondrial dysfunction are a decrease in the rate of oxygen consumption, an increase in the permeability of the inner membrane, and swelling of the mitochondria. These changes occur due to toxic poisoning, infectious disease, hypoxia. 4.5. Total ratings received: 92.
