The main sources of energy for the body are carbohydrates, proteins, mineral s alts, 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, promote the growth and reproduction of new cells that appear in place of dying ones. In the form in which they are eaten, they cannot be absorbed and used by the body. Only water, as well as vitamins and mineral s alts, are digested and absorbed in the form in which they come.
The main sources of energy for the body are proteins, carbohydrates, fats. In the digestive tract, they are subjected not only to physical influences (grind 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 that is the basis of life. This compound is a protein. Protein bodies were discovered by the biochemist Gerard Mulder in 1838. It was he who formulated the theory of protein. The word "protein" from the Greek language means "in first place." Approximately half of the dry weight of any organism is made up of proteins. In viruses, this content ranges from 45-95 percent.
When talking about what is the main source of energy in the body, one cannot ignore protein molecules. They occupy a special place in biological functions and significance.
Functions and location in the body
About 30% of protein compounds are located in the muscles, about 20% are found in tendons and bones, and 10% are found in the skin. The most important for organisms are enzymes that control metabolic chemical processes: digestion of food, activity of the endocrine glands, brain function, and 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 transformation of proteins in the body
Hittingin 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. When the temperature rises, the protein molecule coagulates. Molecules are known that can dissolve in water only when heated. For example, gelatin has such properties.
After absorption, food first enters the oral cavity, then it moves through the esophagus, enters the stomach. It contains an acid reaction of the environment, which is provided by hydrochloric acid. Gastric juice contains the enzyme pepsin, which breaks down protein molecules into albumoses and peptones. This substance is active only in an acidic environment. The food that has entered the stomach is able to stay in it for 3-10 hours, depending on its state of aggregation and nature. Pancreatic juice has an alkaline reaction, it contains enzymes that can break down fats, carbohydrates, proteins.
Among its main enzymes, trypsin is isolated, which is located in the pancreatic juice in the form of trypsinogen. It is not able to break down proteins, but upon contact with intestinal juice, it turns into an active substance - enterokinase. Trypsin breaks down proteins into amino acids. The processing of food in the small intestine ends. If in the duodenum and in the stomach fats, carbohydrates, proteins are almost completely decomposed, then in the small intestine there is a complete breakdown of nutrients, the absorption of reaction products into the blood. The process is carried out through capillaries, each of whichapproaches 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 bloodstream. It also contains a small amount of polypeptides. From the amino acid residues in the body of a living being, a specific protein is synthesized that a person or animal needs. The process of formation of new protein molecules proceeds continuously in a living organism, since dying cells of the skin, blood, intestines, and mucous membranes are removed, and young cells are formed in their place.
In order for proteins to be synthesized, it is necessary that they enter the digestive tract with food. If the polypeptide is introduced into the blood, bypassing the digestive tract, the human body is unable to use it. Such a process can negatively affect the state of the human body, cause numerous complications: fever, respiratory paralysis, cardiac failure, general convulsions.
Proteins cannot be replaced by other food substances, since 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
Let's start with the fact that carbohydrates are the body's main source of energy. They are one of the main groups of organic compounds that ourorganism. 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 energy sources of living organisms are monosaccharides: glucose, fructose, ribose.
Carbohydrates contain oxygen, hydrogen, carbon atoms. For example, glucose - a source of energy in the body, has the formula C6H12O6. There is a division of all carbohydrates (by structure) into simple and complex compounds: mono- and polysaccharides. According to the number of carbon atoms, monosaccharides are divided into several groups:
- trios;
- tetroses;
- pentoses;
- hexoses;
- heptoses.
Monosaccharides that have five or more carbon atoms can form a ring structure when dissolved in water.
The main source of energy in the body is glucose. Deoxyribose and ribose are carbohydrates of particular importance for nucleic acids and ATP.
Glucose is the main source of energy in the body. The processes of transformation of monosaccharides are directly related to the biosynthesis of many organic compounds, as well as the process of removing toxic compounds from it, which come from outside or are formed as a result of the breakdown of protein molecules.
Distinctive features of disaccharides
Monosaccharide and disaccharide is the main source of energy for the body. When combinedmonosaccharides are split off, and the product of the interaction is a disaccharide.
Sucrose (cane sugar), m altose (m alt sugar), lactose (milk sugar) are typical representatives of this group.
Such a source of energy for the body as disaccharides deserves detailed study. They are highly soluble in water and have a sweet taste. Excessive consumption of sucrose leads to serious malfunctions in the body, which is why 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 energy is released, used by a living cell.
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, do not have a chemical and osmotic effect on the cell. Such properties allow them to persist 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 a source of energy for the body is able to resist pathogenic bacteria that enter the body with food. If necessary, during hydrolysis, the transformation of sparepolysaccharides into simple sugars.
Carb exchange
How does the body's main source of energy behave? Carbohydrates are supplied 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, thanks to several intermediate reactions, it is broken down into carbon dioxide and water. After the final oxidation, energy is released, which the body uses.
The process of splitting m alt sugar and starch takes place directly in the oral cavity, the enzyme ptyalin acts as a catalyst for the reaction. In the small intestine, carbohydrates break down into monosaccharides. They are absorbed into the blood mainly in the form of glucose. The process takes place in the upper intestines, but there are almost no carbohydrates in the lower ones. Together with the 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 circulation.
It is necessary to maintain a constant amount of sugar in the blood near 0.1%. With excessive ingestion of saccharides into the blood, the 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 itscontent in the blood. This process is called alimentary or nutritional hyperglycemia. Excess sugar is excreted by the kidneys, so urine contains glucose.
The kidneys begin to remove sugar from the body if its level in the blood reaches the range of 0.15-0.18%. A similar phenomenon occurs with a one-time use of a significant amount of sugar, passes quickly enough, without leading to serious violations of metabolic processes in the body.
If the intrasecretory work of the pancreas is disturbed, 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, 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 required in the implementation of chemical reactions that occur during muscle contractions.
On the importance of glucose
The value of glucose for a living organism is not limited to the energy function. The need for glucose increases with heavy physical work. This need is met by the breakdown of glycogen in the liver into glucose, which enters the bloodstream.
This monosaccharide is also found in the protoplasm of cells, therefore it is required for the formation of new cells, glucose is especially relevant during growth. This monosaccharide is of particular importance for the full functioning of the central nervous system. As soon as the concentration of sugar in the blood drops to 0.04%,convulsions occur, the person loses consciousness. This is a direct confirmation that a decrease in blood sugar causes an instant disruption of the activity of the central nervous system. If the patient is injected with glucose into the blood or is offered sweet food, all disorders disappear. With a prolonged decrease in blood sugar, hypoglycemia develops. It leads to serious disruption of the body, which can cause death.
Fat in brief
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, they are compounds of the polyhydric alcohol glycerol and fatty carboxylic acids.
During the digestive process, fat is broken down into its component parts from which it was derived. It is fats that are an integral part of protoplasm, are contained in tissues, organs, cells of a living organism. They are rightfully considered an excellent source of energy. The breakdown of these organic compounds begins in the stomach. Gastric juice contains lipase, which converts fat molecules into glycerol 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 lipase on fat increases up to 15-20 times. From the stomach, food moves to the duodenum, where, under the action of juice, it is further broken down into products that can be absorbed into the lymph and blood.
Next food gruelmoves through the digestive tract, enters the small intestine. Here it is completely broken down under the influence of intestinal juice, as well as absorption. Unlike the breakdown products of proteins and carbohydrates, substances obtained from the hydrolysis of fats are absorbed into the lymph. Glycerin and soap, after passing through the cells of the intestinal mucosa, combine again to form fat.
Summing up, we note that the main sources of energy for the human body and animals are proteins, fats, carbohydrates. It is thanks to carbohydrate, protein metabolism, accompanied by the formation of additional energy, that a living organism functions. Therefore, you should not go on diets for a long time, limiting yourself in any particular trace element or substance, otherwise it may adversely affect he alth and well-being.
