Fats are one of the most important organic substances needed by all living things. In this article, we will look at the structure and function of lipids. They are diverse both 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.
Simple lipids
The structure of this group of lipids provides for the presence of two components: alcohol and fatty acids. Typically, the chemical composition of such substances includes only three elements: carbon, hydrogen and oxygen.
Varieties of simple lipids
They are divided into three groups:
- Alkylacylates (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 (trihydric alcohol) and residues of higher fatty acids in the composition.
- Ceramides. Esters of sphingosine and fatty acids.
Complex lipids
The substances of this group do not consist of three elements. Apart fromthem, they include in their composition most often sulfur, nitrogen and phosphorus.
Classification of complex lipids
They can also be divided into three groups:
- Phospholipids. The structure of 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 formed by the combination of lipids with carbohydrates.
- Sphingolipids. These are derivatives of aliphatic amino alcohols.
The first two types of lipids, in turn, are divided into subgroups.
Thus, phosphoglycerolipids can be considered as varieties of phospholipids (they contain glycerol, residues of two fatty acids, phosphoric acid and amino alcohol), cardiolipins, plasmalogens (they contain unsaturated monohydric higher alcohol, phosphoric acid and amino alcohol) and sphingomyelins (substances that are composed of sphingosine, fatty acid, phosphoric acid, and the amino alcohol choline).
Types of glycolipids include cerebrosides (except for sphingosine and fatty acid, they 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 function 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 interfacephase section.
Lipids have eight main functions:
- Energy. Due to the oxidation of these substances, the body receives more than 30 percent of all the energy it needs.
- Structural. The structural features of lipids allow them to be an important component of the membranes. They are part of the membranes, line various organs, form membranes of nerve tissues.
- Reserve. These substances are a form of storage of fatty acids by the body.
- Antioxidant. The structure of lipids allows them to perform such a role in the body.
- Regulatory. Some lipids are mediators of hormones in cells. In addition, certain hormones are formed from lipids, as well as substances that stimulate immunogenesis.
- Protective. The subcutaneous layer of fat provides thermal and mechanical protection of the animal's body. As for plants, waxes form a protective shell on the surface of leaves and fruits.
- Informational. Ganglioside lipids provide contacts between cells.
- Digestive. Bile acids are formed from lipid cholesterol, which are involved in the process of digestion of food.
Synthesis of lipids in the body
Most substances of this class are synthesized in the cell from the same starting substance - acetic acid. Fat metabolism is regulated by hormones such as insulin, adrenaline and pituitary hormones.
There are also lipids that the body cannot produce on its own. They must fallinto the human body with food. They are found mainly in vegetables, fruits, herbs, nuts, cereals, sunflower and olive oils and other plant products.
Lipids-vitamins
Some vitamins, by their chemical nature, belong to the class of lipids. These are vitamins A, D, E and K. They must be ingested with food.
| Vitamin | Functions | Manifestation of lack | Sources |
| Vitamin A (retinol) | Participates in the growth and development of epithelial tissue. It is part of rhodopsin, a visual pigment. | Dry and flaky skin. Visual impairment in poor lighting. | Liver, spinach, carrots, parsley, red peppers, apricots. |
| Vitamin K (phylloquinone) | Participates in calcium metabolism. Activates proteins responsible for blood clotting, takes part in the formation of bone tissue. | Ossification of cartilage, impaired blood clotting, s alt deposition on vessel walls, bone deformity. Vitamin K deficiency is very rare. | Synthesized by gut bacteria. Also found in lettuce, nettle, spinach, cabbage. |
| Vitamin D (calciferol) | Takes part in calcium metabolism, formation of bone tissue and tooth enamel. | Rickets | Fish oil, egg yolk, milk, butter. Synthesized in the skin under the influence of ultraviolet radiation. |
| Vitamin E (tocopherol) | Stimulates the immune system. Participates in tissue regeneration. Protects cell membranes from damage. | Increasing the permeability of cell membranes, reducing immunity. | Vegetables, vegetable oils. |
So we looked at the structure and properties of lipids. Now you know what these substances are, what are the differences between different groups, what role do lipids play in the human body.
Conclusion
Lipids are complex organic substances that are divided into simple and complex. They perform eight functions in the body: energy, storage, structural, antioxidant, protective, regulatory, digestive and informational. In addition, there are lipid-vitamins. They perform many biological functions.
