The composition of lipids in biology. What is lipid metabolism. Impact on the reproductive system.
Question 1. What substances are lipids?
Lipids are a broad group of organic compounds, including fats and fat-like substances. They are sparingly soluble in water, but readily soluble in ether, gasoline, chloroform, and some other solvents. Most lipids are composed of macromolecular acids and the trihydric alcohol glycerol.
As a result of this arrangement, bilayer lipids or small lipid spheres can be formed, which can be formed as a single layer with a non-polar central core or a double layer enclosing the polar phase in the center. Despite their similarities in terms of solubility, in terms of chemical structure, lipids are very different because they include esters and hydrocarbons and at the same time can be acyclic, cyclic or polycyclic.
Lipid complex Lipipid complex Lipipid lipids. . Neutral fat, which is in a liquid state, takes the name of oil. Waxes: they are made up of esters fatty acids with special alcohol. Based on this classification, lipids are classified into 8 classes.
Question 2. What is the structure of most lipids?
Differentiate between simple and complex lipids. Molecules of simple lipids consist of residues of fatty acids and alcohols. This group includes fats.
Complexes of lipids with molecules of other substances, such as proteins and carbohydrates, are classified as complex lipids.
Question 3. What are the functions of lipids?
Fatty acids glycerolipids glycerophospholipids sphingolipids glycolipids and polyketides sterols and foams. Polycytes are an important class of natural lipids, including antibiotics, hypocholesterolemics, immunosuppressants, and pigments produced by plants and microorganisms, polyuchet disynthetase.
Lipids can also be distinguished between saponified and non-saponified based on the property of soap formation for alkaline hydrolysis of ester bonds. Alkali metal salts of fatty acids are well known soaps. Saponification is associated with the presence of at least one fatty acid radical in the lipid molecule and is associated with the hydrolysis of the external bond between the fatty acid and the alcohol. In the presence of sodium or potassium hydroxide, saponifiable lipids undergo hydrolysis and release the corresponding alcohol and sodium or potassium salt of a fatty acid, that is, soap.
Energy function. It lies in the fact that fats, as the most common lipids, serve as a valuable source of energy. When they are broken down, energy is released twice as much as when the same amount of glucose is broken down.
protective function. In animals and humans adipose tissue protects internal organs body from damage from falls and bumps. And since adipose tissue does not conduct heat well, lipids protect the body from hypothermia, which is especially important for inhabitants of areas with a cold climate.
structural function. In a cell, lipids perform a structural (building) function: they are part of cell membranes - thin dense films that “dress” all cells and most intracellular organelles.
regulatory function. Many hormones are derivatives of lipids.
storage function. fat stores in subcutaneous tissue mammals allow them to survive unfavorable periods associated with a lack of food and water.
Sodium soaps are called "hard" and are used in solid form, while potassium salts are called "soft" and are used in liquid or paste form. Fatty acids are classified according to the length of the carbon chain. Along their length, they take a different route of blood circulation.
Short chain fatty acids from 1 to 6 carbons Medium chain fatty acids from 6 to 6 carbons Long chain fatty acids from 13 to 13 carbons Very long chain fat from 22 years of age.
Fatty acids based on the absence or presence of double bonds in the carbon chain, which also depend on the melting point of the fatty acids themselves, can be classified as. Saturated fatty acids, consisting of a saturated carbon chain consisting exclusively of single C-C connections in the carbon chain. There are many forms of saturated fatty acids in nature, which differ in the number of carbon atoms. Saturated fats are usually of animal origin and are found in animal tissue, although they can also be of plant origin, such as oil. Coconut oil, cottonseed oil and palm oil.
Animals living in deserts receive a significant part of the water necessary for life through the breakdown of fats in the body.
Question 4. What cells and tissues are richest in lipids?
The cells of adipose tissue in animals are richest in lipids.
The concentration of lipids is high in the seeds of some plants, such as sunflower, flax, and peanuts. And at certain types Plant lipids are found in large quantities in fruits. The fruits of the tropical avocado plant are especially rich in fats.
Unsaturated fatty acids, if there are double bonds in the carbon chain. They can take a cis or trans conformation depending on the conformational geometry of the molecule. Fat families include omega-3, omega-6, and omega-9. Table 2 - Monounsaturated fatty acids.
Specific types of fatty acids. Some fatty acids are trans-saturated fatty acids, branched or non-natural isomers, produced by bacterial fermentation in the rumen and during the hydrogenation of unsaturated acids. Table 3 - Polyunsaturated fatty acids.
This page searched for:
- what substances are lipids
- what are the functions of lipids
- which cells and tissues are richest in lipids
- What is the structure of most lipids?
- What substances are lipids?
Lipids (from the Greek lipos - ether) are a complex mixture of ether-like organic compounds with loved ones physical and chemical properties. Lipids are widely used in the production of many food products, they are important components food products, largely determining their nutritional and biological usefulness and taste.
Essential unsaturated fatty acids. Because some unsaturated fatty acids are considered essential, they can also be classified according to their association with certain metabolic processes. Table 4 - Examples of omega-3, omega-6 and omega-9 unsaturated fatty acids.
Glycerides are either saponifiable fats formed by a glycerol molecule and 1 to 3 fatty acid molecules. Glycerides are called monoglycerides, diglycerides or triglycerides depending on the presence of 1, 2 or 3 fatty acid molecules. Triglycerides are most commonly found in animal and vegetable fats. They have a predominantly energetic function. Mono- and glycerides play a role in intermediate metabolism, while triglycerides are the main body fat in connective tissue.
In plants, lipids accumulate mainly in seeds and fruits and vary from a few percent in cereals and cereals to tens of percent in oilseeds. In animals and fish, lipids are concentrated in the subcutaneous, brain, and nervous tissues. The lipid content in fish varies from 8 to 25%, in carcasses of terrestrial animals it varies greatly: 33% (pork), 9.8% (beef). in milk various kinds animal lipid content ranges from 1.7% in mare's milk to 34.5% in the milk of female reindeer.
Lipids are ternary organic compounds that are insoluble in water and soluble in non-polar solvents such as ether and benzene. In terms of nutrition, they are divided into. From a chemical point of view, they are divided into. It is called a carboxy functional group of an organic molecule, consisting of an oxygen atom bonded in a double bond to a carbon atom, which is also bonded to a hydroxyl group.
Fatty acids, the main components of lipids, are molecules made up of a chain of carbon atoms, called an aliphatic chain, with one carboxyl group at one end. The aliphatic chain that forms them tends to be linear and only in rare cases is it presented in a branched or cyclic form. The length of this chain is extremely important as it affects the physicochemical characteristics of the fatty acid. The hand that is stretched, the water solubility decreases and increases, reflecting the melting point.
Lipids are insoluble in water (hydrophobic*), readily soluble in organic solvents (gasoline, diethyl ether, chloroform, etc.).
By chemical structure lipids are derivatives of fatty acids, alcohols, aldehydes built using ester, ether, phosphoester, glycosidic bonds. Lipids are divided into two main groups: simple and complex lipids. Simple neutral lipids include derivatives of higher fatty acids and alcohols: glycerolipids, waxes, cholesterol esters, glycolipids and other compounds. Molecules of complex lipids contain in their composition not only the remains of high-molecular carboxylic acids, but also phosphoric, sulfuric acids or nitrogen.
Fatty acids usually have an equal number of carbon atoms, although some foods, such as vegetable oils, we find the minimum percentages with odd numbers. Depending on the presence or absence of one or more double bonds in the aliphatic chain, fatty acids are defined as.
Saturated when their chemical structure does not contain double bonds, unsaturated when they have one or more double bonds. Depending on the position of the hydrogen atoms bonded to the double bonded carbon atoms, a fatty acid can exist in nature in two forms: cis and trans.
The most important and widespread group of simple neutral lipids are acylglycerols (or glycerides). These are esters of glycerol and higher carboxylic acids. They make up the bulk of lipids (sometimes up to 95%) and, in fact, they are called fats or oils. The composition of fats includes mainly triacylglycerols (I), less often diacylglycerols (II) and monoacylglycerols (III):
The presence of a double bond in the aliphatic chain suggests the existence of two conformations. The cis form lowers the melting point of the fatty acid and increases its fluidity. In nature, cis and fatty acids predominate over trans, which are mainly formed by certain artificial treatments. For example, during the grinding process necessary to ensure their nutritional suitability, seed oils are enriched with trans fatty acids. A similar speech for the production of margarine, which occurs in the process of hydrogenation of vegetable oils.
The most important representatives of complex lipids are phospholipids- mandatory components of plants (0.3-1.7%). Their molecules are built from residues of alcohols (glycerol, sphingosine), fatty acids, phosphoric acid (H3PO4), and also contain nitrogenous bases, amino acid residues and some other compounds.
The molecules of most phospholipids are built according to general principle. They include, on the one hand, hydrophobic, characterized by low affinity for water, on the other hand, hydrophilic groups (residues of phosphoric acid and nitrogenous base). They are called "polar heads". Due to this property (amphiphilicity), phospholipids often form an interface (membrane) between water and the hydrophobic phase in living organism systems and foods.
Two identical fatty acids, but having a cis-compatible and transforming bond, have different names. The figure shows a fatty acid with eight carbon atoms, with unsaturation in the ninth position and cis conformation; its trans isomer, present in very low percentages, takes on a different name.
The Importance of Double Bonding Stereoisomerism
We see the image, on the left - a saturated fatty acid, we notice a perfectly linear aliphatic chain. FROM right side we see the same fatty acid with a trans type. The chain undergoes a slight reduction but remains a linear structure similar to that of a saturated fatty acid.
Lipids perform not only an energy function (free lipids), but also perform a structural function: together with proteins and carbohydrates, they are part of cell membranes and cellular structures. In terms of mass, structural lipids make up a much smaller group of lipids (3-5% in oilseeds). These are hard-to-remove "bound" and "strongly bound" lipids.
Even better, we can evaluate the bending of the chain caused by the presence of a double cis bond. Finally, on the far right, there is strong folding associated with the presence of two cis double unsaturated bonds. Today food industry can use alternative hydrogenation technologies to produce a vegetable fat without dangerous trans fatty acids, but with the same organoleptic characteristics.
However, they are artificially managed, unnatural, and possibly low quality or low quality oils. Also, they still have a high saturated fatty acid content just because they are semi-solid at room temperature.