Lipids - what is it? Translated from Greek, the word "lipids" means "small particles of fat." They are a group of compounds of natural organics of an extensive nature, including directly fats, as well as fat-like substances. They are part of all living cells without exception and are divided into simple and complex categories. The composition of simple lipids includes alcohol and fatty acids, and complex ones contain high molecular weight components. Both are associated with biological membranes, have an effect on active enzymes, and also participate in the formation of nerve impulses that stimulate muscle contraction.
Fats and hydrophobia
One of the functions of lipids is to create an energy reserve of the body and provide water-repellent properties of the skin, coupled with thermal insulation protection. Some fatty substances that do not have fatty acids are also classified as lipids, for example, sterols and terpenes. Lipids are not susceptible to the effects of the aquatic environment, but are easily soluble in organic liquids such as chloroform, benzene, acetone.
Lipids, the presentation of which is periodically held at international seminars in connection with new discoveries, are an inexhaustible topic for research and scientific research. The question "Lipids - what is it?" never loses its relevance. However, scientific progress does not stand still. Recently, several new fatty acids have been identified that are in biosynthetic relationship with lipids. The classification of organic compounds can be difficult due to the similarity in certain characteristics, but with significant differences in other parameters. Most often, a separate group is created, after which the overall picture of the harmonious interaction of related substances is restored.
Cell membranes
Lipids - what is it in terms of functional purpose? First of all, they are an essential component of living cells and tissues of vertebrates. Most processes in the body occur with the participation of lipids, the formation of cell membranes, the interconnection and signal exchange in the intercellular medium are not complete without fatty acids.
Lipids - what is it when viewed from the perspective of spontaneously arising steroid hormones, phosphoinositides and prostaglandins? This is, first of all, the presence in the blood plasma of saturated fatty acids, which, by definition, are separate components of lipid structures. Due to the hydrophobic properties of the latter, the body is forced to develop complex systems for their transportation. Lipid fatty acids are mainly transported in combination with albumin, and water-soluble lipoproteins are transported in the usual manner.
Lipid classification
The distribution of compounds of biological nature into categories is a process associated with some problems of a controversial nature. Lipids in connection with biochemical and structural properties can be assigned equally to different categories. The main classes of lipids include simple and complex compounds.
The simple ones include:
- Glycerides - esters of glycerol alcohol and fatty acids of the highest category.
- Waxes - ester of higher fatty acid and 2-atomic alcohol.
Complex lipids:
- Phospholipid compounds - with the inclusion of nitrogenous components, glycerophospholipids, ofingolipids.
- Glycolipids - located in the external biological layers of the body.
- Steroids are highly active substances in the animal spectrum.
- Complex fats - sterols, lipoproteins, sulfolipids, aminolipids, glycerol, hydrocarbons.
Functioning
Lipid fats act as a material for cell membranes. Participate in the transportation of various substances on the periphery of the body. Fat layers based on lipid structures help protect the body from hypothermia. They have the function of energy storage "in reserve".
Fat reserves are concentrated in the cytoplasm of cells in the form of drops. Vertebrate animals, including humans, have special cells - adipocytes, which are capable of containing a lot of fat. The placement of fat accumulations in adipocytes occurs due to lipoid enzymes.
Biological functions
Fat is not only a reliable source of energy, it also has heat-insulating properties, which biology contributes to. In this case, lipids can achieve several useful functions, such as natural cooling of the body or, conversely, its thermal insulation. In the northern regions, characterized by low temperatures, all animals accumulate fat, which is deposited throughout the body evenly, and thus creates a natural protective layer that performs the function of thermal protection. This is especially important for large marine animals: whales, walruses, seals.
Animals living in hot countries also accumulate body fat, but in them they are not distributed throughout the body, but are concentrated in certain places. For example, in camels, fat is collected in the humps, in desert animals - in thick, short tails. Nature carefully monitors the proper placement of both fat and water in living organisms.
The structural function of lipids
All processes associated with the life of the body are subject to certain laws. Phospholipids are the basis of the biological layer of cell membranes, and cholesterol regulates the fluidity of these membranes. Thus, most living cells are surrounded by double-lipid plasma membranes. This concentration is necessary for normal cellular activity. One microparticle of a biomembrane contains more than a million lipid molecules that have double characteristics: they are both hydrophobic and hydrophilic. As a rule, these mutually exclusive properties are nonequilibrium in nature, and therefore their functional purpose looks quite logical. Lipids in the cell are an effective natural regulator. The hydrophobic layer usually dominates and protects the cell membrane from the penetration of harmful ions.
Glycerophospholipids, phosphatidylethanolamine, phosphatidylcholine, cholesterol also contribute to cell impermeability. Other membrane lipids are located in tissue structures, these are sphingomyelin and sphingoglycolipid. Each substance performs a specific function.
Lipids in the human diet
Triglycerides - neutral fats , are an effective source of energy. Saturated fatty acids have meat and dairy products. And fatty acids, but unsaturated, are found in nuts, sunflower and olive oil, seeds and grains of corn. To ensure that the level of cholesterol does not increase in the body, it is recommended that the daily rate of animal fats be limited to 10 percent.
Lipids and carbohydrates
Many organisms of animal origin “put” fats at certain points, subcutaneous tissue, in the folds of the skin, and other places. The lipid oxidation of such fat deposits occurs slowly, and therefore the process of their transition to carbon dioxide and water allows you to get a significant amount of energy, almost two times more than carbohydrates can give. In addition, the hydrophobic properties of fats eliminate the need to use large amounts of water to stimulate hydration. The transition of fats to the energy phase occurs "dry." However, fats act much more slowly in terms of energy release, and are more suitable for animals in hibernation. Lipids and carbohydrates seem to complement each other during the life of the body.