What are lipids? Biochemistry pays special attention to this class of organic compounds. Let us consider in more detail the features of their structure, as well as properties, functions, applications.
Theoretical aspects
Lipids (fats) are low molecular weight organic substances that are partially or completely insoluble in water. They can be extracted from cells of plants, animals, microorganisms using non-polar organic solvents (benzene, ether, chloroform).
How are lipids secreted? The biochemistry of these compounds is based on the features of their chemical composition and structure. They have fatty acids, alcohols, phosphoric acid, heterocyclic nitrogenous bases, carbohydrates. It is difficult to give a single definition of lipids, given how many-sided their chemical structure.
Biological importance
How does lipid metabolism work? Biochemistry is characterized by numerous functions performed by these compounds: reserve, energy, structural, regulatory, protective. Let's analyze them in more detail:
- Structural function. Lipids, together with proteins, are structural components of biological cell membranes, that is, they affect their permeability, take an active part in the transmission of a nerve impulse, in the formation of intercellular interaction.
- Energy function. It is lipids that are called "cellular" energy-intensive fuel. The oxidation of one gram of fat is accompanied by the release of 39 kJ of energy, which is 2 times higher than the oxidation of carbohydrates.
- Reserve function. It consists in the accumulation of additional energy in the cell. Reservation is carried out in fat cells - adipocytes. The body of an adult contains 6-10 kg of lipids.
- Protective function. Fats are characterized by thermal insulation properties, thanks to which they protect the body from physical and mechanical damage. In plants, thanks to the wax coating, protection against infections and water conservation are guaranteed.
- Regulatory function. Lipids are considered precursors of vitamins, hormones (thromboxanes, prostaglandins, leukotrienes). This function also manifests itself depending on the activity of membranes on the properties and composition of lipids.
It's important to know
What is lipid metabolism? Human biochemistry depends on fat metabolism. In case of its violation, various pathological conditions arise: metabolic acidosis, obesity, atherosclerosis, cholelithiasis. How does lipid oxidation occur? Biochemistry of blood - what is it? To find answers to these questions, we turn to theirclassification.
Department
Lipids include LDL, triglycerides, cholesterol, HDL. For the human body, only certain lipid compounds that are in the blood in the maximum amount are important. The rest are not so important, since the concentration of these lipoproteins is minimal. What is the classification of lipids based on? Biochemistry involves the allocation of three groups:
- 1 group. LDL (low density lipoproteins), which are "bad" cholesterol, are dangerous to humans when their concentration in the blood increases. Such fats quickly accumulate on the walls of vascular structures, reducing the lumen. This contributes to a number of cardiovascular diseases (atherosclerosis).
- 2 group. HDL (high density lipoproteins) are "good" cholesterol, help to minimize the accumulation of "bad" fat in the vessels. How are lipids digested? Biochemistry assumes their circulation through the human vascular systems, as a result of which the accumulation of LDL on their walls is prevented.
- 3 group. Triglycerides, which are compounds of several fatty acids, as well as two protein molecules. They are derivatives of glycerol, a source of energy for the functioning of body cells, active participants in biological processes.
Lipid profile
It is unacceptable to change the concentration of triglycerides either in the direction of decrease or increase. These trends indicate the development of pathologicalstate in the body.
Also in the classification of blood lipids, cholesterol esters and phospholipids are distinguished. These indicators are needed for profile research. A lipid profile is a set of blood tests that allows you to identify abnormalities in the metabolism of fats in a particular organism. It can be considered synonymous with lipidogram. Such a study consists in identifying the concentration of fats in the blood. The profile includes a quantitative indicator of basic blood fats ("good" and "bad"), their comparison.
Purpose of the lipid profile
It allows you to identify pathologies of the cardiovascular system, assess the risks of forming an individual predisposition to an increased amount of lipids in the blood. The results of the lipid profile should be analyzed by a professional. For each individual, the concept of “norm” varies, depending on many parameters: lifestyle, hereditary diseases.
Destination option
Lipid tests are essential for diagnosing atherosclerosis. Lipidogram is an optional examination. As part of the basic prevention of certain diseases, it is necessary to carry it out at intervals of 1-2 times a year. Among the specific indications for such an analysis, experts consider the following problems:
- extrahepatic jaundice;
- postponed myocardial infarction;
- diabetes mellitus;
- atherosclerosis;
- oncological lesions of the pancreas;
- intoxicationorganism;
- sepsis;
- obesity of varying degrees;
- kidney failure;
- anorexia.
If a person has at least one of the pathologies listed above, the frequency of lipid analysis is 1 time in 6 months. Lipidogram is considered the most important study to prevent the risks of complications of diseases, to monitor the possibility of their therapy.
How the examination is done
It is necessary to take blood from the cubital vein for analysis in the morning (on an empty stomach). Prior to determining the lipid profile, preliminary correct preparation is necessary in order to avoid distortions in laboratory studies.
Among the basic preparatory measures are: donating blood in the morning, giving up alcohol, smoking, excessive stress, stress (at least a day). The lipidogram is carried out in this way. The diagnostician is talking to the patient. If there are no contraindications, a blood test is performed from a vein or phalanx of the finger. Next, the biomaterial is sent to the laboratory for analysis. Based on the results, a diagnostic sheet is drawn up, which describes in detail the lipid profile of the examined patient. The results are handed over to a person, or redirected to a specialist.
Summarize
Lipids are a group of organic substances that include fats and lipoids (fat-like compounds). Fats, found in all cells, are a natural barrier. They limit cell permeability, are included incomposition of hormones. They are hydrophobic substances that form an emulsion with water. Lipids are highly soluble in organic solvents (alcohols, acetone, benzene). Without fat, the full functioning of the human body is impossible. Lipid metabolism disorders negatively affect the condition, lead to serious diseases.
