Fats are one of the most important organic substances that all living things need. In this article we will consider the structure and functions of lipids. They are diverse in structure and function.
The structure of lipids (biology)
Lipid is a complex organic chemical compound. It consists of several components. Let's look at the structure of lipids in more detail.
The structure of lipids of this group provides for the presence of two components: alcohol and fatty acids. Usually the chemical composition of such substances includes only three elements: carbon, hydrogen and oxygen.
Varieties of simple lipids
They are divided into three groups:
- Alkyl acylates (waxes). These are esters of higher fatty acids and mono- or dihydric alcohols.
- Triacylglycerols (fats and oils). The structure of lipids of this type provides for the presence of glycerol (triatomic alcohol) and residues of higher fatty acids.
- Ceramides. Esters of sphingosine and fatty acids.
Substances of this group consist of not three elements. In addition to them, they include in their composition more often sulfur, nitrogen and phosphorus.
Classification of complex lipids
They can also be divided into three groups:
- Phospholipids. The structure of the lipids of this group provides, in addition to the residues of polyhydric alcohols and higher fatty acids, the presence of phosphoric acid residues to which additional groups of various elements are attached.
- Glycolipids. These are chemicals that are formed as a result of the connection of lipids with carbohydrates.
- Sphingolipids. These are derivatives of aliphatic aminoalcohols.
The first two types of lipids, in turn, are divided into subgroups.
For example, phosphoglycerol lipids (containing glycerin, residues of two fatty acids, phosphoric acid and amino alcohol), cardiolipins, plasmalogens (contain an unsaturated monohydric higher alcohol, phosphoric acid and amino alcohol) and sphingomyelins (substances that comprise From sphingosine, fatty acid, phosphoric acid and choline amino alcohol).
Types of glycolipids include cerebrosides (except for sphingosine and fatty acid, contain galactose or glucose), gangliosides (contain oligosaccharide from hexoses and sialic acids) and sulfatides (sulfuric acid is attached to hexose).
The role of lipids in the body
The structure and functions of lipids are interrelated. Due to the fact that polar and nonpolar structural fragments are simultaneously present in their molecules, these substances can function at the interface of phases.
Lipids have eight basic functions:
- Energy. Due to the oxidation of these substances, the body receives more than 30 percent of all the energy it needs.
- Structural. The peculiarities of the structure of lipids allow them to be an important component of the membranes. They are part of the membrane, lining various organs, form membranes of nerve tissues.
- Inventory. These substances are a form of saving the body with fatty acids.
- Antioxidant. The structure of lipids allows them to perform such a role in the body.
- Regulatory. Some lipids mediate hormones in cells. In addition, some hormones are formed from lipids, as well as substances that stimulate immunogenesis.
- Protective. The subcutaneous fat layer provides thermal and mechanical protection of the animal's body. As for plants, a protective shell on the surface of leaves and fruits is formed from waxes.
- Informational. Lipids gangliosides provide contact between cells.
- Digestive. Of the lipid cholesterol formed bile acids involved in the process of digesting food.
Synthesis of lipids in the body
Most substances of this class are synthesized in a cell from the same starting material, acetic acid. Regulate the metabolism of fats such hormones as insulin, adrenaline and pituitary hormones.
There are also lipids, which the body can not produce on its own. They must necessarily enter the human body with food. They are contained mainly in vegetables, fruits, herbs, nuts, cereals, sunflower and olive oils and other products of plant origin.
Some vitamins are chemically related to the class of lipids. They are vitamins A, D, E and K. They must enter the human body with food.
|Vitamin A (retinol)||Participates in the growth and development of epithelial tissue. It is part of the rhodopsin - the visual pigment.||Dryness and flaking of the skin. Visual impairment in poor light.||Liver, spinach, carrots, parsley, red pepper, apricots.|
|Vitamin K (phylloquinone)||Participates in the exchange of calcium. Activates proteins responsible for blood clotting, takes part in the formation of bone tissue.||Ossification of cartilage, disruption of blood clotting, deposition of salts on the walls of blood vessels, deformation of bones. Vitamin K deficiency happens very rarely.||It is synthesized by bacteria of the intestine. Also found in leaves of lettuce, nettle, spinach, cabbage.|
|Vitamin D (calciferol)||It takes part in the exchange of calcium, the formation of bone tissue and enamel of teeth.||Rickets||Fish oil, yolk of eggs, milk, butter. It is synthesized in the skin under the influence of ultraviolet.|
|Vitamin E (tocopherol)||Stimulates immunity. Participates in the regeneration of tissues. Protects cell membranes from damage.||Increase the permeability of cell membranes, decrease immunity.||Vegetables, vegetable oils.|
So we examined the structure and properties of lipids. Now you know what these substances are, what are the differences of different groups, what role do lipids play in the human body.
Lipids are complex organic substances that are divided into simple and complex. They perform eight functions in the body: energy, storing, structural, antioxidant, protective, regulatory, digestive and information. In addition, there are lipid-vitamins. They perform many biological functions.