Lipids - what is it? Lipids: functions, characteristics

Lipids - what is it? In Greek, the word "lipids" means "small particles of fat." They represent a group of compounds of natural organic substances of a broad 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 contains high-molecular components. Both are related to biological membranes, have an effect on active enzymes, and also participate in the formation of nerve impulses that stimulate muscle contractions.

Fats and hydrophobia

One of the functions of lipids is the creation of an energy reserve of the body and the provision of water-repellent properties of the skin combined with thermal insulation protection. Some fatty substances that do not have fatty acids are also classified as lipids, for example, sterols and terpenes. Lipids can not be influenced by the aqueous environment, but they readily dissolve in organic liquids such as chloroform, benzene, acetone.

Lipids, the presentation of which is periodically held at international seminars in connection with new discoveries, is an inexhaustible topic for research and scientific research. The question "Lipids - what is it?" Never loses its relevance. Nevertheless, scientific progress does not stand still. Recently, several new fatty acids have been identified that are in biosynthetic relationship with lipids. Classification of organic compounds can be difficult due to similarity in certain characteristics, but with a significant difference in other parameters. Most often a separate group is created, after which the general picture of the harmonious interaction of related substances is restored.

Cell Membrane

Lipids - what is this in terms of functional purpose? First of all, they are the most important component of living cells and tissues of vertebrates. Most of the processes in the body occur with the participation of lipids, the formation of cell membranes, the interrelation and exchange of signals in the intercellular environment do not do without fatty acids.

Lipids - what is it, if they are viewed from the standpoint of spontaneously emerging 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. Because of the hydrophobic properties of the latter, the body is forced to produce complex systems for their transportation. Fatty acids of lipids are mainly transferred in a complex with albumins, and lipoproteins soluble in water are transported in the usual way.

Classification of lipids

The distribution of compounds that are of a biological nature, by category, is a process associated with some controversial problems. Lipids in connection with biochemical and structural properties can be attributed equally to different categories. The main classes of lipids include simple and complex compounds.

The simple ones are:

• Glycerides are esters of glycerol alcohol and fatty acids of the highest category.
• Waxes - ester of higher fatty acid and 2-atom alcohol.

Complex lipids:

• Phospholipid compounds - with the inclusion of nitrogenous components, glycerophospholipids, ophitolipids.
• Glycolipids - located in the outer biological layers of the body.
• Steroids are highly active substances in the animal spectrum.
• Complex fats - sterols, lipoproteins, sulfolipids, aminolipids, glycerol, hydrocarbons.

Operation

Lipid fats serve as a material for cell membranes. They participate in the transportation of various substances around the periphery of the body. Fat layers on the basis of lipid structures help to protect the body from hypothermia. Have the function of energy storage "in reserve."

The stores of fats concentrate in the cytoplasm of cells in the form of droplets. Vertebrate animals, including humans, possess special cells - adipocytes, which can contain a lot of fat. The location of fat accumulation in adipocytes is due to lipid enzymes.

Biological functions

Fat is not only a reliable source of energy, it also has heat-insulating properties, which is promoted by biology. Lipids at the same time can achieve several useful functions, such as natural cooling of the body or, conversely, its thermal insulation. In northern regions, characterized by low temperatures, all animals accumulate fat, which is deposited throughout the body evenly, and thus creates a natural protective layer, performing the function of heat protection. This is especially important for large marine animals: whales, walruses, seals.

Animals living in hot countries also accumulate fatty deposits, but they do not distribute them throughout the body, but concentrate in certain places. For example, in camels fat is collected in humps, desert animals have thick, short tails. Nature carefully monitors the proper placement of both fat and water in living organisms.

Structural function of lipids

All processes associated with the life of the organism, 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 plasma membranes with a double layer of lipids. This concentration is necessary for normal cellular activity. In one microparticle of biomembrane contains more than one million lipid molecules, which have dual characteristics: they are both hydrophobic and hydrophilic. As a rule, these mutually exclusive properties are nonequilibrium, and therefore their functional purpose looks quite logical. Lipids in the cell is 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 promote cell impermeability. In the tissue structures are located other membrane lipids, this is sphingomyelin and sphingoglycolipid. Each substance performs a certain function.

Lipids in the human diet

Triglycerides - fats of a neutral nature, are an effective source of energy. Fatty acids are rich in meat and dairy products. And the acids are fatty, but unsaturated, contained in nuts, sunflower and olive oil, seeds and corn kernels. To ensure that the body does not increase cholesterol, it is recommended that the daily limit of animal fats be limited to 10 percent.

Lipids and carbohydrates

Many organisms of animal origin "stack" the fats at certain points, subcutaneous tissue, in folds of the skin, in other places. Oxidation of lipids of such fatty deposits is slow, and therefore the process of their transition into carbon dioxide and water allows to obtain a significant amount of energy, almost twice as much as carbohydrates can give. In addition, the hydrophobic properties of fats relieve the need to use a large amount of water to stimulate hydration. The transition of fats to the energy phase occurs "dry". However, fats are much slower in terms of energy release, and are more suitable for animals in a state of hibernation. Lipids and carbohydrates seem to complement each other in the process of vital activity of the body.