Characteristics of lipids Lipids are a combined group of organic compounds that do not have a single chemical characteristic. They are united by the fact that they are all derivatives of higher fatty acids, insoluble in water, but highly soluble in organic solvents (ether, chloroform, gasoline). Lipids are found in all cells of animals and plants. The content of lipids in cells is 1 - 5% of dry mass, but in adipose tissue it can sometimes reach 90%.
Characteristics of lipids Depending on the structural features of the molecules, there are: Simple lipids, which are two-component substances that are esters of higher fatty acids and any alcohol. Complex lipids having multicomponent molecules: phospholipids, lipoproteins, glycolipids. Lipoids, which include steroids - polycyclic alcohol cholesterol and its derivatives.
Characterization of lipids Simple lipids. 1. Fats. Fats are widely distributed in nature. They are part of the human body, animals, plants, microbes, some viruses. The content of fats in biological objects, tissues and organs can reach 90%. Fats are esters of higher fatty acids and the trihydric alcohol glycerol. In chemistry, this group of organic compounds is called triglycerides. Triglycerides are the most abundant lipids in nature.
Characterization of lipids Usually, all three hydroxyl groups of glycerol react, so the reaction product is called a triglyceride. Physical properties depend on the composition of their molecules. If saturated fatty acids predominate in triglycerides, then they are solid (fats), if unsaturated liquid (oils). The density of fats is lower than that of water, so they float in water and are on the surface.
Characteristics of lipids Complex lipids: Phospholipids, glycolipids, lipoproteins, lipoids 1. Phospholipids. As a rule, a phospholipid molecule has two higher fatty acid residues and one phosphoric acid residue. Phospholipids are found in both animals and plants. Phospholipids are present in all cells of living beings, participating mainly in the formation of cell membranes.
Characteristics of lipids 2. Lipoproteins are derivatives of lipids with various proteins. Some proteins penetrate the membrane - integral proteins, others are immersed in the membrane to different depths - semi-integral proteins, and others are located on the outer or inner surface of the membrane - peripheral proteins. 3. Glycolipids are carbohydrate derivatives of lipids. The composition of their molecules, along with phospholipids, also includes carbohydrates. 4. Lipoids are fat-like substances. These include sex hormones, some pigments (chlorophyll), some vitamins (A, D, E, K).
Functions of lipids 1. The main function of lipids is energy. Lipids are higher in calories than carbohydrates. During the breakdown of 1 g of fat to CO 2 and H 2 O, 38.9 kJ are released. 2. Structural. Lipids take part in the formation of cell membranes. The membranes contain phospholipids, glycolipids, lipoproteins. 3. Spare. This is especially important for animals that hibernate during the cold season or make long transitions through areas where there are no food sources. The seeds of many plants contain the fat needed to provide energy to the developing plant.
4. Thermoregulatory. Fats are good thermal insulators due to poor thermal conductivity. They are deposited under the skin, forming thick layers in some animals. For example, in whales, the layer of subcutaneous fat reaches a thickness of 1 m. 5. Protective-mechanical. Accumulating in the subcutaneous layer, fats protect the body from mechanical influences. Functions of lipids
6.Catalytic. This function is associated with fat-soluble vitamins (A, D, E, K). By themselves, vitamins do not have catalytic activity. But they are coenzymes; without them, enzymes cannot perform their functions. 7. Source of metabolic water. One of the products of fat oxidation is water. This metabolic water is very important for desert dwellers. So, the fat with which the camel's hump is filled is primarily not a source of energy, but a source of water (when 1 kg of fat is oxidized, 1.1 kg of water is released). 8. Increasing buoyancy. Fat reserves increase the buoyancy of aquatic animals. Functions of lipids
Test 1. With the complete combustion of 1 g of the substance, 38.9 kJ of energy was released. This substance refers to: 1. Carbohydrates. 2. To fats. 3. Or to carbohydrates, or to lipids. 4. To proteins. Test 2. The basis of cell membranes is formed by: 1. Fats. 2. Phospholipids. 3.Wax. 4. Lipids. Test 3. Statement: "Phospholipids esters of glycerol (glycerol) and fatty acids": Correct. Wrong. Repetition:
**Test 4. Lipids perform the following functions in the body: 1.Structural.5. Some are enzymes. 2. Energy.6. Source of metabolic water 3. Heat-insulating.7. Reserve. 4.Some are hormones.8. These include vitamins A, D, E, K. ** Test 5. A fat molecule consists of residues: 1. Amino acids. 2.Nucleotides. 3.Glycerin. 4.Fatty acids. Test 6. Glycoproteins are a complex: 1. Proteins and carbohydrates. 2.Nucleotides and proteins. 3.Glycerin and fatty acids. 4.Carbohydrates and lipids. Repetition:
Grade 10
Lipids
INORGANIC COMPOUNDS
ORGANIC COMPOUNDS
Water 75-85%
Proteins 10-20%
Inorganic substances 1-1.5%
Fats 1-5%
Carbohydrates 0.2-2%
Nucleic acids 1-2%
Low molecular weight organic compounds - 0.1-0.5%
Lipids - a combined group of organic compounds that do not have a single chemical characteristic. They are united by the fact that they are all derivatives of higher fatty acids, insoluble in water, but highly soluble in organic solvents (gasoline, ether, chloroform).
Lipid classification
COMPLEX LIPIDS
(multicomponent molecules)
SIMPLE LIPIDS
(two-component substances that are esters of higher fatty acids and any alcohol)
Simple lipids
Fats are widely distributed in nature. They are part of the human body, animals, plants, microbes, some viruses. The content of fats in biological objects, tissues and organs can reach 90%.
Fats - These are esters of higher fatty acids and a trihydric alcohol - glycerol. In chemistry, this group of organic compounds is called triglycerides. Triglycerides are the most abundant lipids in nature.
Fatty acid
More than 500 fatty acids have been found in the composition of triglycerides, the molecules of which have a similar structure. Like amino acids, fatty acids have the same grouping for all acids - a carboxyl group (–COOH) and a radical by which they differ from each other. Therefore, the general formula of fatty acids is R-COOH. The carboxyl group forms the head of the fatty acid. It is polar and therefore hydrophilic. The radical is a hydrocarbon tail, which differs in different fatty acids in the number of –CH2 groups. It is non-polar and therefore hydrophobic. Most fatty acids contain an even number of carbon atoms in the "tail", from 14 to 22 (most often 16 or 18). In addition, the hydrocarbon tail may contain varying amounts of double bonds. By the presence or absence of double bonds in the hydrocarbon tail, there are:
saturated fatty acids, not containing double bonds in the hydrocarbon tail;
unsaturated fatty acids having double bonds between carbon atoms (-CH=CH-).
Formation of a triglyceride molecule
When a triglyceride molecule is formed, each of the three hydroxyl (-OH) groups of glycerol reacts
condensation with fatty acid (Fig. 268). During the reaction, three ester bonds are formed, so the resulting compound is called an ester. Usually, all three hydroxyl groups of glycerol enter into the reaction, so the reaction product is called triglyceride.
Rice. 268. Formation of a triglyceride molecule.
Properties of triglycerides
Physical properties depend on the composition of their molecules. If saturated fatty acids predominate in triglycerides, then they are solid (fats), if unsaturated fatty acids are liquid (oils).
The density of fats is lower than that of water, so they float in water and are on the surface.
Waxes- a group of simple lipids, which are esters of higher fatty acids and higher high-molecular alcohols.
Waxes are found in both the animal and vegetable kingdoms, where they perform mainly protective functions. In plants, for example, they cover leaves, stems and fruits with a thin layer, protecting them from wetting with water and the penetration of microorganisms. The shelf life of fruits depends on the quality of the wax coating. Honey is stored under the cover of beeswax and larvae develop. Other types of animal wax (lanolin) protect hair and skin from water.
Complex lipids
Phospholipids
Phospholipids- esters of polyhydric alcohols with higher fatty acids containing
Rice. 269. Phospholipid.
phosphoric acid residue (Fig. 269). Sometimes additional groupings (nitrogenous bases, amino acids, glycerol, etc.) can be associated with it.
As a rule, in a phospholipid molecule there are two residues of higher fatty and
one residue of phosphoric acid.
Phospholipids are found in both animals and plants. Especially a lot of them in the nervous tissue of humans and vertebrates, a lot of phospholipids in the seeds of plants, the heart and liver of animals, eggs of birds.
Phospholipids are present in all cells of living beings, participating mainly in the formation of cell membranes.
Glycolipids
Glycolipids are carbohydrate derivatives of lipids. The composition of their molecules, along with polyhydric alcohol and higher fatty acids, also includes carbohydrates (usually glucose or galactose). They are localized predominantly on the outer surface of the plasma membrane, where their carbohydrate components are among other cell surface carbohydrates.
Lipoids- fat-like substances. These include steroids (cholesterol, estradiol and testosterone, which are widely distributed in animal tissues, respectively, female and male sex hormones), terpenes (essential oils on which the smell of plants depends), gibberellins (plant growth substances), some pigments (chlorophyll, bilirubin) , part of vitamins (A, D, E, K), etc.
Functions of lipids
Energy
The main function of lipids is energy. Lipids are higher in calories than carbohydrates. During the breakdown of 1 g of fat to CO2 and H2O, 38.9 kJ are released. The only food of newborn mammals is milk, the energy content of which is determined mainly by its fat content.
Structural
Lipids take part in the formation of cell membranes. The membranes contain phospholipids, glycolipids, lipoproteins.
Reserve
Fats are the reserve substance of animals and plants. This is especially important for animals that hibernate during the cold season or make long transitions through areas where there are no food sources (camels in the desert). The seeds of many plants contain the fat needed to provide energy to the developing plant.
Thermoregulatory
Fats are good thermal insulators due to poor thermal conductivity. They are deposited under the skin, forming thick layers in some animals. For example, in whales, the layer of subcutaneous fat reaches a thickness of 1 m. This allows a warm-blooded animal to live in cold water. The adipose tissue of many mammals plays the role of a thermoregulator.
Protective mechanical
Accumulating in the subcutaneous layer, fats not only prevent heat loss, but also protect the body from mechanical influences. Fat capsules of the internal organs, the fat layer of the abdominal cavity provide fixation of the anatomical position of the internal organs and protect them from concussion, injury from external influences.
catalytic
This function is associated with fat-soluble vitamins (A, D, E, K). By themselves, vitamins do not have catalytic activity. But they are cofactors of enzymes; without them, enzymes cannot perform their functions.
Metabolic water source
One of the products of fat oxidation is water. This metabolic water is very important for desert dwellers. So, the fat with which the camel's hump is filled is primarily not a source of energy, but a source of water (when 1 kg of fat is oxidized, 1.1 kg of water is released).
Increase in buoyancy
Fat reserves increase the buoyancy of aquatic animals.
Lipid classification
Simple lipids
Complex lipids
Fats (triglycerides)
Wax
Lipid classification
Simple lipids
Complex lipids
Phospholipids– (glycerol + phosphoric acid + fatty acid)
Fats (triglycerides)- esters of high molecular weight fats. acids and the trihydric alcohol glycerol
Glycolipids(lipid + carbohydrate)
Wax- esters of higher fatty acids. acids and alcohols
Lipoproteins(lipid + protein)
FATS (triglycerides)
Fats are widely distributed in nature. They are part of the human body, animals, plants, microbes, some viruses. The content of fats in biological objects, tissues and organs can reach 90%.
GENERAL FATS FORMULA:
The density of fats is lower than that of water, so they float in water and are on the surface.
triglycerides
FATS
OILS
are of animal origin
are of plant origin
solid
liquid
contains saturated fatty acids
Contains unsaturated fatty acids
WAXES
This is a group of simple lipids, which are esters of higher fatty acids and higher high molecular weight alcohols.
Bees build honeycombs from wax.
STRUCTURE OF A PHOSPHOLIPIDE MOLECULE
(hydrophilic, consists of glycerol and a phosphoric acid residue)
head
(hydrophobic, composed of residues of fatty acids)
tails
phospholipids
Phospholipids are found in both animals and plants.
Phospholipids are present in all cells of living beings, participating mainly in the formation of cell membranes.
GLYCOLIPIDS
Glycolipids are found in the myelin sheath of nerve fibers and on the surface of neurons, and are also components of chloroplast membranes.
The structure of the nerve fiber
Chloroplast
LIPOPROTEINS
In the form of lipoproteins, lipids are carried in the blood and lymph.
For example, cholesterol is carried by blood through the vessels as part of the so-called lipoproteins - complex complexes consisting of fats and proteins, and having several varieties.
FUNCTIONS OF LIPID
Function
Characteristic
Example
FUNCTIONS OF LIPID
Function
Characteristic
1. Energy
Example
2 O + CO 2 + 38.9 kJ
FUNCTIONS OF LIPID
Function
Characteristic
1. Energy
Example
When 1 g of fat is oxidized, H 2 O + CO 2 + 38.9 kJ
a) before 40% of energy the body receives from lipid oxidation;
b) every hour, 25 g of fat goes into the general bloodstream, which goes to the formation of energy.
FUNCTIONS OF LIPID
Function
Characteristic
2. Storage
Example
a) subcutaneous fat
STORAGE FUNCTION OF LIPID
This is especially important for animals that hibernate during the cold season or make long transitions through areas where there are no food sources.
Brown bear
Pink salmon
FUNCTIONS OF LIPID
Function
Characteristic
2. Storage
Example
Spare source E, because fats - "energy canned food"
b) a drop of fat inside the cell
fatty
drops
Core
The seeds and fruits of plants contain the fat necessary to provide energy to the developing plant.
FUNCTIONS OF LIPID
Function
Characteristic
Example
a) phospholipids are part of cell membranes
FUNCTIONS OF LIPID
Function
Characteristic
3. Structural (plastic)
Example
b) glycolipids are part of the myelin sheaths of nerve cells
FUNCTIONS OF LIPID
Function
Characteristic
4. Thermoregulatory
Example
Subcutaneous fat protects animals from hypothermia
a) in whales, the subcutaneous layer of fat reaches 1 m, which allows a warm-blooded animal to live in the cold water of the polar ocean
FUNCTIONS OF LIPID
Function
Characteristic
5. Protective
Example
a) a layer of fat (omentum) protects the delicate organs from shock and shock
(eg, perirenal capsule, fat pad near the eyes)
FUNCTIONS OF LIPID
Function
Characteristic
5. Protective
Example
Fats protect against mechanical stress
b) wax covers the leaves of plants with a thin layer, preventing them from getting wet during heavy rains, as well as feathers and wool
FUNCTIONS OF LIPID
Function
Characteristic
6. Source of endogenous (metabolic)
Example
Czech) water
Jerboa
Gerbil
FUNCTIONS OF LIPID
Function
Characteristic
6. Source of endogenous water
Example
When 100 g of fat is oxidized, 107 ml of water is released
a) Thanks to such water, many deserts exist. animals (e.g. jerboas, gerbils, camels)
A camel may not drink for 10-12 days.
FUNCTIONS OF LIPID
Function
Characteristic
7. Regulator
Example
Many fats are components of vitamins and hormones
a) fat-soluble vitamins - D, E, K, A
FUNCTIONS OF LIPID
Function
Characteristic
8. Solvents for hydrophobic compounds
Example
Allows fat-soluble substances to enter the body
a) vitamins E, D, A
Repetition:
Test 1. With the complete combustion of 1 g of the substance, 38.9 kJ of energy was released. This substance is:
- To carbohydrates.
- To fats.
- Or to carbohydrates, or to lipids.
- To squirrels.
Test 2. The basis of cell membranes is formed by:
- Fats.
- Phospholipids.
- Wax.
- Lipids.
Test 3. Statement: "Phospholipids are esters of glycerol (glycerol) and fatty acids":
Wrong.
Repetition:
** Test 4. Lipids perform the following functions in the body:
- Structural. 5. Some are enzymes.
- Energy. 6. Source of metabolic water
- Heat insulating. 7. Reserve.
- Some are hormones. 8. These include vitamins A, D, E, K.
**Test 5. A fat molecule consists of residues:
- Amino acids.
- Nucleotides.
- Glycerin.
- fatty acids.
Test 6. Glycoproteins are a complex:
- Proteins and carbohydrates.
- Nucleotides and proteins.
- Glycerin and fatty acids.
- Carbohydrates and lipids.
* * Lipids Cholesterol Groups lipid Functions Vitamins * * Lipids are a complex mixture of organic compounds found in plants, animals and microorganisms. Their common features are: insolubility in water (hydrophobicity) and good solubility in organic solvents (gasoline, diethyl ether, chloroform, etc.). *Lipids are often divided into two groups: Simple lipids These are lipids, the molecule of which does not contain nitrogen, phosphorus, sulfur atoms. Simple lipids include: higher carboxylic acids; waxes; triol and diol lipids; glycolipids. Complex lipids These are lipids, the molecule of which contains nitrogen and/or phosphorus atoms, as well as sulfur. * The main function of lipids is energy. Lipids are higher in calories than carbohydrates. During the breakdown of 1 g of fat, 38.9 kJ are released. Reserve. This is especially important for animals that hibernate during the cold season or make long transitions through areas where there are no food sources. Structural. Lipids take part in the formation of cell membranes. * Thermoregulatory. Fats are good thermal insulators due to poor heat conduction. They are deposited under the skin, forming thick layers in some animals. For example, in whales, the layer of subcutaneous fat reaches a thickness of 1 m. Protective-mechanical. Accumulating in the subcutaneous layer, fats protect the body from mechanical influences. * Source of metabolic water. One of the products of fat oxidation is water. This metabolic water is very important for desert dwellers. So, the fat with which the camel's hump is filled is primarily not a source of energy, but a source of water. * Increased buoyancy. Fat reserves increase the buoyancy of aquatic animals. For example, thanks to subcutaneous fat, the body of walruses weighs about the same as the water it displaces. *Lipids (fats) are very important in nutrition, because they contain a number of vitamins - A, O, E, K and fatty acids important for the body, which synthesize various hormones. They are also part of the tissue and, in particular, the nervous system. Certain lipids are directly responsible for increasing blood cholesterol levels. Consider: 1. Fats that raise cholesterol These are saturated fats found in meat, cheese, lard, butter, dairy and smoked products, and palm oil. 2. Fats that contribute little to the formation of cholesterol. They are found in oysters, eggs, and skinless poultry. 3. Fats that lower cholesterol. These are vegetable oils: olive, rapeseed, sunflower, corn and others. Fish oil plays no role in cholesterol metabolism, but prevents cardiovascular disease. Therefore, the following varieties of fish (the most fatty) are recommended: chum and salmon, tuna, mackerel, herring, sardines.
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Slides captions:
Lipids are a complex mixture of organic compounds found in plants, animals and microorganisms. Their common features are: insolubility in water (hydrophobicity) and good solubility in organic solvents (gasoline, diethyl ether, chloroform, etc.).
Lipids are often divided into two groups: Simple lipids Complex lipids These are lipids, the molecule of which does not contain nitrogen, phosphorus, sulfur atoms. Simple lipids include: higher carboxylic acids; waxes; triol and diol lipids; glycolipids. These are lipids, the molecule of which contains nitrogen and/or phosphorus, as well as sulfur atoms.
The main function of lipids is energy. Lipids are higher in calories than carbohydrates. During the breakdown of 1 g of fat, 38.9 kJ are released. Structural. Lipids take part in the formation of cell membranes. Reserve. This is especially important for animals that hibernate during the cold season or make long transitions through areas where there are no food sources.
Thermoregulatory. Fats are good thermal insulators due to poor heat conduction. They are deposited under the skin, forming thick layers in some animals. For example, in whales, the layer of subcutaneous fat reaches a thickness of 1 m. Protective-mechanical. Accumulating in the subcutaneous layer, fats protect the body from mechanical influences.
Source of metabolic water. One of the products of fat oxidation is water. This metabolic water is very important for desert dwellers. So, the fat with which the camel's hump is filled is primarily not a source of energy, but a source of water.
Increased buoyancy. Fat reserves increase the buoyancy of aquatic animals. For example, thanks to subcutaneous fat, the body of walruses weighs about the same as the water it displaces.
Lipids (fats) are very important in nutrition, because they contain a number of vitamins - A, O, E, K and fatty acids important for the body, which synthesize various hormones. They are also part of the tissue and, in particular, the nervous system.
Certain lipids are directly responsible for increasing blood cholesterol levels. Consider: 1. Fats that raise cholesterol These are saturated fats found in meat, cheese, lard, butter, dairy and smoked products, and palm oil. 2. Fats that contribute little to the formation of cholesterol. They are found in oysters, eggs, and skinless poultry. 3. Fats that lower cholesterol. These are vegetable oils: olive, rapeseed, sunflower, corn and others. Fish oil plays no role in cholesterol metabolism, but prevents cardiovascular disease. Therefore, the following varieties of fish (the most fatty) are recommended: chum and salmon, tuna, mackerel, herring, sardines.
