The main sources of energy for the body are carbohydrates, proteins, mineral salts, fats, vitamins. They ensure its normal activity, allow the body to function without any problems. Nutrients are sources of energy in the human body. In addition, they act as a building material, contribute to the growth and reproduction of new cells that appear at the place of dying. In the form in which they are eaten, it is impossible to absorb and use the body. Only water, as well as vitamins and mineral salts are absorbed and absorbed in the form in which they enter.
The main sources of energy for the body are proteins, carbohydrates, fats. In the digestive tract, they are subjected not only to physical influences (rubbed and crushed), but also to chemical transformations that occur under the influence of enzymes that are in the juice of special digestive glands.
Protein structure
In plants and animals there is a certain substance, which is the basis of life. This compound is a protein. The discovered protein bodies were biochemist Gerard Mulder in 1838. It was he who formulated the theory of protein. The word "protein" from the Greek language means "taking first place." About half the dry weight of any organism is made up of proteins. In viruses, this content ranges from 45-95 percent.
Talking about what is the main source of energy in the body, protein molecules cannot be ignored. They occupy a special place in biological functions and significance.
Functions and location in the body
About 30% of the protein compounds are located in the muscles, about 20% are found in the tendons and bones, and 10% is found in the skin. The most significant for organisms are enzymes that control metabolic chemical processes: the digestion of food, the activity of the endocrine glands, the brain, muscle activity. Even small bacteria contain hundreds of enzymes.
Proteins are an essential part of living cells. They contain hydrogen, carbon, nitrogen, sulfur, oxygen, and some also contain phosphorus. An obligatory chemical element contained in protein molecules is nitrogen. That is why these organic substances are called nitrogen-containing compounds.
Properties and conversion of proteins in the body
Once in the digestive tract, they are broken down into amino acids, which are absorbed into the bloodstream and used to synthesize an organism-specific peptide, then oxidized to water and carbon dioxide. As the temperature rises, the protein molecule coagulates. Such molecules are known that can dissolve in water only when heated. For example, gelatin has such properties.
After absorption, the food first appears in the oral cavity, then it moves along the esophagus and enters the stomach. It contains an acidic reaction of the medium, which is provided by hydrochloric acid. In the gastric juice there is the enzyme pepsin, which breaks down protein molecules into albumoses and peptones. This substance is active only in an acidic environment. The food that enters the stomach can linger in it for 3-10 hours, depending on its state of aggregation and nature. Pancreatic juice has an alkaline reaction, it has enzymes that can break down fats, carbohydrates, and proteins.
Among its main enzymes, trypsin is isolated, which in the pancreatic juice is located in the form of trypsinogen. It is not able to break down proteins, but when it comes into contact with intestinal juice it turns into an active substance - enterokinase. Trypsin breaks down protein compounds into amino acids. Processing of food in the small intestine is ending. If fats, carbohydrates, proteins almost completely break down in the duodenum and stomach, then in the small intestine there is a complete breakdown of nutrients, absorption of reaction products into the blood. The process is carried out through capillaries, each of which approaches the villi located on the wall of the small intestine.
Protein metabolism
After the protein is completely broken down into amino acids in the digestive tract, they are absorbed into the blood. Also, a small amount of polypeptides gets into it. From the amino acid residues in the body of a living creature, a specific protein is synthesized, which a person or animal needs. The process of the formation of new protein molecules proceeds continuously in a living organism, since the dying cells of the skin, blood, intestines, mucous membrane are removed, and young cells are formed in their place.
In order for the synthesis of proteins, it is necessary that they, together with food, enter the digestive tract. If a polypeptide is introduced into the blood, bypassing the digestive tract, the human body is not able to use it. A similar process can negatively affect the state of the human body, causing numerous complications: fever, respiratory paralysis, cardiac failure, general cramps.
Proteins cannot be replaced with other nutrients, because amino acids are necessary for their synthesis inside the body. An insufficient amount of these substances leads to a delay or suspension of growth.
Saccharides
To begin with, carbohydrates are the main energy source of the body. They represent one of the main groups of organic compounds that our body needs. This energy source of living organisms is the primary product of photosynthesis. The content of carbohydrates in a living plant cell can fluctuate in the range of 1-2 percent, and in some situations this figure reaches 85-90 percent.
The main sources of energy of living organisms are monosaccharides: glucose, fructose, ribose.
In the composition of carbohydrates there are atoms of oxygen, hydrogen, carbon. For example, glucose - an energy source in the body, has the formula C6H12O6. There is a subdivision of all carbohydrates (by structure) into simple and complex compounds: mono- and polysaccharides. By the number of carbon atoms, monosaccharides are divided into several groups:
- trioses;
- tetrosis;
- pentoses;
- hexoses;
- heptoses.
Monosaccharides, which contain five or more carbon atoms, when dissolved in water, can form a ring structure.
The main source of energy in the body is glucose. Deoxyribose and ribose are carbohydrates of particular importance to nucleic acids and ATP.
Glucose is the main source of energy in the body. The biosynthesis of many organic compounds, as well as the process of removing poisonous compounds from it or that are formed as a result of the breakdown of protein molecules, is directly related to the processes of conversion of monosaccharides.
Distinctive features of disaccharides
Monosaccharide and disaccharide are the main source of energy for the body. When monosaccharides are combined, cleavage occurs, and the disaccharide acts as the interaction product.
Typical representatives of this group include sucrose (cane sugar), maltose (malt sugar), lactose (milk sugar).
A source of energy for the body like disaccharides deserves a detailed study. They are highly soluble in water, have a sweet taste. Excessive use of sucrose leads to serious malfunctions in the body, so it is so important to comply with the rules.
Polysaccharides
An excellent source of energy for the body are substances such as cellulose, glycogen, starch.
First of all, any of them can be considered as a source of energy for the human body. In the case of their enzymatic cleavage and decay, a large amount of the energy used by the living cell is released.
This source of energy for the body performs other important functions. For example, chitin, cellulose are used as a building material. Polysaccharides are excellent for the body as reserve compounds, since they do not dissolve in water and do not have a chemical and osmotic effect on the cell. Such properties allow them to remain for a long time in a living cell. When dehydrated, polysaccharides are able to increase the mass of stored products due to volume savings.
Such an energy source for the body is able to withstand pathogenic bacteria that enter the body with food. If necessary, during hydrolysis, the conversion of storage polysaccharides to simple sugars occurs.
Carbohydrate metabolism
How does the main source of energy in the body behave? Carbohydrates come to a greater extent in the form of polysaccharides, for example, in the form of starch. As a result of hydrolysis, glucose is formed from it. The monosaccharide is absorbed into the blood, due to several intermediate reactions, it is split into carbon dioxide and water. After the final oxidation, the energy that the body uses is released.
The process of splitting malt sugar and starch occurs directly in the oral cavity, the enzyme ptyalin acts as a catalyst for the reaction. In the small intestines, carbohydrates break down to monosaccharides. They are absorbed into the blood mainly in the form of glucose. The process takes place in the upper intestines, but in the lower carbohydrates there is almost no. Together with blood, saccharides enter the portal vein and reach the liver. In the case when the concentration of sugar in human blood is 0.1%, carbohydrates pass through the liver and end up in the general bloodstream.
It is necessary to maintain a constant amount of sugar in the blood of about 0.1%. With excessive ingestion of saccharides in the blood, excess accumulates in the liver. A similar process is accompanied by a sharp drop in blood sugar.
Change in body sugar
If starch is present in food, this does not lead to large-scale changes in blood sugar, since the process of hydrolysis of the polysaccharide takes a long time. If the dose of sugar leaves about 15-200 grams, there is a sharp increase in its content in the blood. This process is called alimentary or food hyperglycemia. Excess sugar is excreted by the kidneys, so urine contains glucose.
Sugars begin to be excreted from the body in the event that its level in the blood reaches a range of 0.15-0.18%. A similar phenomenon occurs with the simultaneous use of a significant amount of sugar, passes quickly enough, without leading to serious metabolic disturbances in the body.
If the intracecretory function of the pancreas is disrupted, a disease such as diabetes mellitus occurs. It is accompanied by a significant increase in the amount of sugar in the blood, which leads to the loss of the ability of the liver to retain glucose by the liver, as a result, sugar is excreted in the urine from the body.
A significant amount of glycogen can be deposited in the muscles, here it is in demand in the implementation of chemical reactions that occur during muscle contractions.
About the importance of glucose
The value of glucose for a living organism is not limited only to energy function. The need for glucose increases with heavy physical work. This need is met by breaking down glycogen in the liver into glucose, which enters the bloodstream.
This monosaccharide is also present in the protoplasm of cells; therefore, it is required for the formation of new cells; glucose during growth is especially relevant. Of particular importance is this monosaccharide for the full activity of the central nervous system. As soon as the blood sugar concentration drops to 0.04%, cramps occur, the person loses consciousness. This is direct confirmation that a decrease in blood sugar causes an instant violation of the central nervous system. If the patient is injected with glucose in the blood or is offered sweet food, all violations disappear. With a prolonged decrease in blood sugar, hypoglycemia develops. It leads to serious disorders of the body that can cause his death.
Briefly about fats
Fats can be considered as another source of energy for a living organism. They contain carbon, oxygen, and hydrogen. Fats have a complex chemical structure, are compounds of polyhydric alcohol glycerol and fatty carboxylic acids.
During digestive processes, fat is broken down into the constituent parts from which it was obtained. It is fats that are an integral part of protoplasm, found in tissues, organs, cells of a living organism. They are considered to be an excellent source of energy. The breakdown of these organic compounds begins in the stomach. Gastric juice contains lipase, which turns fat molecules into glycerin and carboxylic acid.
Glycerin is perfectly absorbed, as it has good solubility in water. Bile is used to dissolve acids. Under its influence, the effectiveness of exposure to lipase fat increases up to 15-20 times. From the stomach, food moves to the duodenum, where, under the action of juice, it further breaks down to products that are able to be absorbed into the lymph and blood.
Further, the food gruel moves along the digestive tract, enters the small intestine. Here it is completely split under the influence of intestinal juice, as well as absorption. Unlike the products of the breakdown of proteins and carbohydrates, substances obtained by hydrolysis of fats are absorbed into the lymph. Glycerin and soaps, after passing through the cells of the intestinal mucosa, combine again, form fat.
Summarizing, we note that the main sources of energy for the human body and animals are proteins, fats, carbohydrates. Thanks to carbohydrate, protein metabolism, accompanied by the formation of additional energy, a living organism functions. Therefore, you should not go on diets for a long time, limiting yourself to a specific microelement or substance, otherwise it can adversely affect health and well-being.