Presentation on the topic of lipids in biology. Carbohydrates, lipids
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Carbohydrates, or saccharides, are organic substances that contain carbon, oxygen, and hydrogen. The chemical composition of carbohydrates is characterized by their general formula Cm(H2O)n, where m≥n. The number of hydrogen atoms in carbohydrate molecules is usually twice the number of oxygen atoms (that is, the same as in a water molecule). Hence the name - carbohydrates.
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Properties of monosaccharides: low molecular weight; sweet taste; easily dissolves in water; crystallize; belong to reducing (reducing) sugars.
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Monosaccharide molecules can be in the form of straight chains or cyclic structures.
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Disaccharides (oligosaccharides) The most widespread disaccharides in nature are: maltose, consisting of two glucose residues; lactose – milk sugar (-glucose + galactose); sucrose – beet sugar (-glucose + fructose).
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Disaccharides are formed by the condensation of two monosaccharides (most often hexoses). The bond that occurs between two monosaccharides is called glycosidic. It usually forms between the 1st and 4th carbon atoms of adjacent monosaccharide units (1,4-glycosidic bond).
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Polysaccharides Properties of polysaccharides: high molecular weight (usually hundreds of thousands); do not produce clearly shaped crystals; either insoluble in water or form solutions resembling colloidal ones in properties; sweet taste is not typical;
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Functions of carbohydrates: Energy. One of the main functions of carbohydrates. Carbohydrates are the main sources of energy in the animal body. When 1 g of carbohydrate is broken down, 17.6 kJ is released. С6Н12О6 + О2 = 6СО2 + 6Н2О + 17.6 kJ Reserve. It is expressed in the accumulation of starch in plant cells and glycogen in animal cells. Support and construction. Carbohydrates are part of cell membranes and cell walls (glycocalyx, cellulose, chitin, murein). Combining with lipids and proteins, they form glycolipids and glycoproteins.
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Ribose and deoxyribose are part of the monomers of DNA, RNA and ATP nucleotides. Receptor. Oligosaccharide fragments of glycoproteins and glycolipids of cell walls perform a receptor function. 6. Protective. The mucus secreted by various glands is rich in carbohydrates and their derivatives (for example, glycoproteins). They protect the esophagus, intestines, stomach, bronchi from mechanical damage, and prevent bacteria and viruses from entering the body.
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Lipids Lipids are a group of organic compounds that do not have a single chemical characteristic. What they have in common is that they are all derivatives of higher fatty acids, insoluble in water, but highly soluble in organic solvents (ether, chloroform, gasoline).
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Depending on the structural features of the molecules, they are distinguished: Simple lipids, which are two-component substances that are esters of higher fatty acids and some alcohol. Complex lipids having multicomponent molecules: phospholipids, lipoproteins, glycolipids. Lipoids, which include steroids - polycyclic alcohol cholesterol and its derivatives.
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Simple lipids. Fats. Fats are widely distributed in nature. They are part of the human body, animals, plants, microbes, and some viruses. The fat content in biological objects, tissues and organs can reach 90%. Fats are esters of higher fatty acids and trihydric alcohol - glycerol. In chemistry, this group of organic compounds is usually called triglycerides. Triglycerides are the most common lipids in nature.
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Waxes are a group of simple lipids, which are esters of higher fatty acids and higher high molecular weight alcohols. Waxes are found in both the animal and plant 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 fruit depends on the quality of the wax coating. Honey is stored under the cover of beeswax and the larvae develop. Other types of animal wax (lanolin) protect hair and skin from the effects of water.
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Complex lipids. Phospholipids are esters of polyhydric alcohols with higher fatty acids, containing a phosphoric acid residue. Sometimes additional groups (nitrogenous bases, amino acids, glycerol, etc.) may be associated with it. Lipoproteins are derivatives of lipids with various proteins. Some proteins penetrate the membrane - integral proteins, others are immersed in the membrane to varying depths - semi-integral proteins, and others are located on the outer or inner surface of the membrane - peripheral proteins.
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Glycolipids are carbohydrate derivatives of lipids. Their molecules, along with polyhydric alcohol and higher fatty acids, also contain carbohydrates (usually glucose or galactose). They are localized primarily on the outer surface of the plasma membrane, where their carbohydrate components are included among other cell surface carbohydrates.
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Lipoids Lipoids are fat-like substances. These include steroids (cholesterol, widespread in animal tissues, its derivatives - estradiol and testosterone - female and male sex hormones, respectively), terpenes (essential oils on which the smell of plants depends), gibberellins (plant growth substances), some pigments (chlorophyll , bilirubin), some vitamins (A, D, E, K), etc.
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Functions of lipids. The main function of lipids is energy. The calorie content of lipids is higher than that of carbohydrates. During the breakdown of 1 g of fats into CO2 and H2O, 38.9 kJ is released. Structural. Lipids take part in the formation of cell membranes. The membranes contain phospholipids, glycolipids, and lipoproteins. Storage. This is especially important for animals that hibernate during the cold season or make long treks through areas where there are no food sources. The seeds of many plants contain fat necessary to provide energy to the developing plant. Thermoregulatory. Fats are good thermal insulators due to their 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. Protective-mechanical. Accumulating in the subcutaneous layer, fats protect the body from mechanical stress.
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Catalytic. This function is associated with fat-soluble vitamins (A, D, E, K). Vitamins themselves do not have catalytic activity. But they are coenzymes; 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 inhabitants. Thus, the fat that fills a camel’s hump serves primarily not as a source of energy, but as a source of water (when 1 kg of fat is oxidized, 1.1 kg of water is released). Increased buoyancy. Fat reserves increase the buoyancy of aquatic animals.
Characteristics of lipids Lipids are a group of organic compounds that do not have a single chemical characteristic. What they have in common is 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 animal and plant cells. The lipid content in cells is 1 - 5% of dry weight, but in adipose tissue it can sometimes reach 90%.
Characteristics of lipids Depending on the structural features of the molecules, they are distinguished: Simple lipids, which are two-component substances that are esters of higher fatty acids and some alcohol. Complex lipids having multicomponent molecules: phospholipids, lipoproteins, glycolipids. Lipoids, which include steroids - polycyclic alcohol cholesterol and its derivatives.
Characteristics of lipids Simple lipids. 1. Fats. Fats are widely distributed in nature. They are part of the human body, animals, plants, microbes, and some viruses. The fat content 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 usually called triglycerides. Triglycerides are the most common lipids in nature.
Characteristics 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, they are liquid (oils). The density of fats is lower than that of water, so in water they float and are on the surface.
Characteristics of lipids Complex lipids: Phospholipids, glycolipids, lipoproteins, lipoids 1. Phospholipids. As a rule, a phospholipid molecule contains 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 things, 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 varying 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. Along with phospholipids, their molecules also contain carbohydrates. 4. Lipoids are fat-like substances. These include sex hormones, some pigments (chlorophyll), and some vitamins (A, D, E, K).
Functions of lipids 1. The main function of lipids is energy. The calorie content of lipids is higher than that of carbohydrates. During the breakdown of 1 g of fats into CO 2 and H 2 O, 38.9 kJ is released. 2.Structural. Lipids take part in the formation of cell membranes. The membranes contain phospholipids, glycolipids, and lipoproteins. 3.Store. This is especially important for animals that hibernate during the cold season or make long treks through areas where there are no food sources. The seeds of many plants contain fat necessary to provide energy to the developing plant.
4.Thermoregulatory. Fats are good thermal insulators due to their 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 stress. Functions of lipids
6.Catalytic. This function is associated with fat-soluble vitamins (A, D, E, K). Vitamins themselves 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 inhabitants. Thus, the fat that fills a camel’s hump serves primarily not as a source of energy, but as a source of water (when 1 kg of fat is oxidized, 1.1 kg of water is released). 8.Increased buoyancy. Fat reserves increase the buoyancy of aquatic animals. Functions of lipids
Test 1. With complete combustion of 1 g of the substance, 38.9 kJ of energy was released. This substance belongs to: 1.Carbohydrates. 2. To fats. 3. Either 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 are 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. Stocking up. 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 of: 1. Proteins and carbohydrates. 2. Nucleotides and proteins. 3.Glycerol and fatty acids. 4.Carbohydrates and lipids. Repetition:
LECTURE PLAN LIPID CHEMISTRY 1. Definition, role, classification. 2. Characteristics of simple and complex lipids. DIGESTION OF LIPIDS IN THE GASTROINTESTINAL TRACT 1. The role of lipids in nutrition. 2. Bile acids. Emulsification. 3. Enzymes. 5. Absorption of hydrolysis products. 6. Features in children. 7. Resynthesis. DIGESTION AND ABSORPTION DISORDERS Steatorrhea. Steatorrhea.
Functions of lipids: Substrate-energy Substrate-energy Structural (component of biomembranes) Structural (component of biomembranes) Transport (lipoproteins) Transport (lipoproteins) Transmission of nerve impulse Transmission of nerve impulse Electrical insulating (myelin fiber) Electrical insulating (myelin fiber) Thermal insulating (low thermal conductivity) Thermal insulating ( low thermal conductivity) Protective Protective Hormonal Hormonal Vitamin Vitamin
By chemical structure 1. Simple: 1) triacylglycerols (neutral fat) - TG, TAG 1) triacylglycerols (neutral fat) - TG, TAG 2) waxes 2) waxes 2. Complex: 1) phospholipids - PL 1) phospholipids - PL a ) glycerophospholipids a) glycerophospholipids b) sphingophospholipids b) sphingophospholipids 2) glycolipids - GL (cerebrosides, gangliosides, sulfatides) 2) glycolipids - GL (cerebrosides, gangliosides, sulfatides) 3) steroids (sterols and sterides) 3) steroids (sterols and sterides ) In relation to water 1. Hydrophobic (form a film on the surface of water) - TG 2. Amphiphilic form: a) bilipid layer - PL, GL (1 head, 2 tails) a) bilipid layer - PL, GL (1 head, 2 tail) b) micelle - MG, Xs, VZHK (1 head, 1 tail) b) micelle - MG, Xs, VZHK (1 head, 1 tail) By biological role 1. reserve (TG) 2. structural - form biological membranes (FL, GL, Xs)
Unsaturated (unsaturated) general formula C n H(2n+1)-2m COOH Monounsaturated: palmitooleic (16:1) C 15 H 29 COOH oleic (18:1) C 17 H 33 COOH Polyunsaturated (vitamin F): linoleic (18 :2) C 17 H 31 COOH linoleic (18:2) C 17 H 31 COOH (ω-6) linolenic (18:3) C 17 H 29 COOH linolenic (18:3) C 17 H 29 COOH (ω-3 ) arachidonic (20:4) C 19 H 31 COOH arachidonic (20:4) C 19 H 31 COOH (ω-6)
The role of polyunsaturated fatty acids (PUFAs) 1. precursors of eicosanoids (prostaglandins, thromboxanes, leukotrienes) - biologically active substances synthesized from PUFAs with 20 carbon atoms, acting as tissue hormones. 2. are part of phospholipids, glycolipids. 3. help remove cholesterol from the body. 4. They are vitamin F (omega 3, omega 6).
Human fat = glycerol + 2 unsaturated + 1 saturated IVH (dioleopalmitin) Animal fat = glycerol + 1 unsaturated + 2 saturated IVH (oleopalmitostearin glycerol + 1 unsaturated + 2 saturated IVH (oleopalmitostearin) Vegetable fat = glycerin + 3 unsaturated IVH (triolein) Write formulas for molecules of neutral fat of plant, animal and human origin independently.
Lysophospholipids Lysophosphatidylcholine (lysolecithin) Contain a free hydroxyl group at the 2nd glycerol atom. They are formed by the action of phospholipase A 2. The membranes in which lysophospholipids are formed become permeable to water, so the cells swell and collapse. (Hemolysis of erythrocytes during the bite of snakes whose venom contains phospholipase A 2)
II. DIGESTION OF LIPIDS IN THE GASTROINTESTINAL TRACT 1. The role of lipids in nutrition 1. The role of lipids in nutrition 2. Bile acids: formation, structure, paired bile acids, role. 2. Bile acids: formation, structure, paired bile acids, role. 3. Emulsification scheme. 3. Emulsification scheme. 4. Digestion enzymes: pancreatic lipase, the chemistry of the action of lipase on triglyceride; phospholipases, cholesterol esterase. 4. Digestion enzymes: pancreatic lipase, the chemistry of the action of lipase on triglyceride; phospholipases, cholesterol esterase. 5. Absorption of lipid hydrolysis products. 5. Absorption of lipid hydrolysis products. 6. Features of lipid digestion in children. 6. Features of lipid digestion in children. 7. Resynthesis of triglycerides and phospholipids in the intestinal wall. 7. Resynthesis of triglycerides and phospholipids in the intestinal wall. III. DISORDERS OF DIGESTION AND ABSORPTION 1. Steatorrhea: causes, types (hepatogenic, pancreatogenic, enterogenic).
ROLE OF LIPIDS IN NUTRITION 1. Food lipids are 99% represented by triglycerides. 2. Lipids come from such food products as vegetable oil - 98%, milk - 3%, butter%, etc. 3. Daily requirement for lipids = 80 g/day (50 g animal +30 g vegetable). 4. Fats provide % of the daily energy requirement. 5. An irreplaceable component of nutrition - polyunsaturated fatty acids (essential), the so-called. Vitamin F is a complex of linoleic, linolenic and arachidonic acids. Daily requirement of vitamin F = 3-16 g. 6. Food lipids serve as solvents for fat-soluble vitamins A, D, E, K. 7. High consumption of saturated fats increases the risk of developing atherosclerosis. Therefore, with age, animal fats are replaced with vegetable fats. 8. Increases the taste of food and provides satiety.
DIGESTION OF LIPIDS IN THE GASTROINTESTINAL TRACT They are not digested in the oral cavity. They are not digested in the mouth. In the stomach only in children (gastric lipase acts only on emulsified milk fats, optimum pH 5.5-7.5). In the stomach only in children (gastric lipase acts only on emulsified milk fats, optimum pH 5.5-7.5). In the small intestine: 1) emulsification, In the small intestine: 1) emulsification, 2) enzymatic hydrolysis. 2) enzymatic hydrolysis. Emulsification factors 1. bile acids 2. CO2 3. fiber 4. peristalsis 5. polysaccharides 6. salts of fatty acids (so-called soaps)
Emulsification mechanism - reducing the surface tension of a fat droplet Emulsification mechanism - reducing the surface tension of a fat droplet The purpose of emulsification is to increase the area of contact of fat molecules with enzyme molecules The purpose of emulsification is to increase the area of contact of fat molecules with enzyme molecules Emulsification scheme:
BILE ACIDS are derivatives of cholanic acid. They are formed in the liver from cholesterol. They are formed in the liver from cholesterol. They are secreted with bile. They are secreted with bile. They circulate up to 10 times. They circulate up to 10 times. ROLE OF BALL ACIDS 1) EMULSIFIATE FATS 2) ACTIVATE LIPASE 3) FORM CHOLEIC COMPLEXES FOR SUCTION ( IVH, MG, Xc, vitamins A, D, E, K)
Pancreatic lipase Optimum pH 7-8 Optimum pH 7-8 Activated by bile acids Activated by bile acids Acts only on emulsified fats (at the fat/water interface) Acts only on emulsified fats (at the fat/water interface)
ABSORPTION OF HYDROLYSIS PRODUCTS OF FOOD LIPIDS 1. CONTAINING CHOLEIN COMPLEXES (MICELLES): - IVFA (with the number of carbon atoms more than 10) - IVFA (with the number of carbon atoms more than 10) - monoacylglycerides - monoacylglycerides - cholesterol - cholesterol - fat-soluble vitamins A, D, E, K - fat-soluble vitamins A, D, E, K 2. By diffusion: glycerol, IVH (with the number of carbon atoms less than 10). 3. Pinocytosis.
IMPAIRED DIGESTION AND ABSORPTION Always accompanied by steatorrhea - the detection of undigested neutral fat in the feces. Types of steatorrhea: 1. Hepatogenic (for liver diseases) – emulsification is impaired in obstructive jaundice, hepatitis, cirrhosis, congenital biliary atresia. There are a lot of TGs in the feces, a high concentration of IVH salts (soaps), especially calcium. Feces are acholic (low bile pigments). 2. Pancreatogenic (for diseases of the pancreas) – hydrolysis is impaired in chronic pancreatitis, congenital hypoplasia, cystic fibrosis. Feces have a high concentration of TG, little IVF, with normal pH and bile acid content.
3. Enterogenous – the absorption of fat hydrolysis products is impaired in diseases of the small intestine, extensive resection of the small intestine, amyloidosis, and a-beta-lipoproteinemia. In feces, the content of IVH increases sharply, the pH shifts to the acidic side, bile pigments are normal.
Triacylglycerols (triglycerides, neutral fats) are esters of trihydric alcohol glycerol and VZhK. Role of TG: energy (storage), heat-insulating, shock-absorbing (mechanical protection). Glycerol General formula of fat VFA (3 molecules) Ester bond - 3 H 2 O esterification
Lysophospholipids Lysophosphatidylcholine (lysolecithin) Contain a free hydroxyl group at the 2nd glycerol atom. Formed by the action of phospholipase B (A 2). The membranes in which lysophospholipids are formed become permeable to water, so the cells swell and collapse. (Hemolysis of erythrocytes during the bite of snakes whose venom contains phospholipase B)
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LIPIDS PLAN
10.1. Classification and biological
role of lipids.
10.2. Saponifiable lipids. Wax,
neutral fats, oils.
10.3. Complex lipids. Phospholipids as
structural components of biological
membranes
10.4. Properties of saponified lipids. 10.1. Classification and
biological role of lipids
Lipids include most
group of substances
plant and animal
origin. These
substances are very
varied in composition and
structure General characteristics of lipids are insoluble in water, soluble in
non-polar and weakly polar
organic solvents (benzene,
petroleum ether, carbon tetrachloride,
diethyl ether).
Using these solvents
lipids are extracted from
plant and animal material Biological role of lipids
1. Lipids (phospholipids) are involved
in the formation of cell membranes;
2.Energy function (1 g fat at
complete oxidation releases 38 kJ of energy);
3.Structural, formative function;
4.Protective function;
5.Lipids serve as a solvent for
fat-soluble vitamins; 6. Mechanical function;
7. Fats are sources of water for
body. When oxidizing 100g of fat
107 g of water are formed;
8. Regulatory function;
9. Fats secreted by skin
glands serve as a lubricant for the skin 10.2. Saponifiable lipids. Wax,
neutral fats, oils
In relation to hydrolysis
Lipids are divided into two groups: saponifiable and unsaponifiable
lipids Saponifiable lipids
hydrolyze in acidic and
alkaline environment
Unsaponifiable lipids
do not undergo hydrolysis The basis of the structure
saponifiable lipids
constitute - the highest
monohydric alcohols,
trihydric alcohol
glycerol, diatomic
unsaturated amino alcohol
- sphingosine Alcohols are acylated with VZhK
In the case of glycerin and
sphingosine one of
alcohol hydroxyls
can be esterified
substituted phosphorus
acid Higher fatty acids (HFAs)
The composition of saponified
lipids include various
carboxylic acids
from C4 to C28 MCA - monocarboxylic acids
straight chain and
even number of carbon atoms,
which is determined by the features
their biosynthesis. Most
common acids with
number of carbon atoms 16-18 CLASSIFICATION OF DRC
Limit DRC
CH3(CH2)14COOH
palmitic acid
C15H31COOH
CH3(CH2)15COOH
margaric acid
C16H33COOH
CH3(CH2)16COOH
stearic acid
С17Н35СООН
Saturated acids - solid
waxy substances Unsaturated liquid-reinforced complexes
CH3(CH2)7CH = CH(CH2)7COOH
С17Н33СООН
oleic acid
Unsaturated IVFAs exist only in cis form
CH 3
10
9
COOH CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH
С17Н31СООН
Linoleic acid
13
CH3
12
10
9
COOH CH3CH2CH=CHCH2CH=CHCH2CH=CH(CH2)7COOH
C17H29COOH
CH3
16
15
13
12
Linolenic acid
10
9
COOH CH3(CH2)4CH=CHCH2CH=CHCH2CH=CHCH2CH=CH(CH2)3COOH
C19H31COOH Arachidonic acid
9
8
6
5
COOH
CH 3
11
12
14
15Oleic acid is
most common in
natural lipids. Makes up
about half of the total mass
acids From saturated liquid liquids
most common –
palmitic and stearic
acids The human body is capable
synthesize saturated
fatty acids, and
unsaturated with one double
communication Unsaturated liquid liquids with
two or more double bonds
must enter the body with
food, mainly
vegetable oils. These
acids are called essential They perform a series
important functions in
particularly arachidonic
acid is
predecessor in
synthesis of prostaglandins, the most important hormonal
bioregulators Prostaglandins cause
decreased arterial
pressure and muscle contraction,
have a wide range
biological activity, in
particularly cause pain
Feel. Analgesics
reduce pain, because suppress
prostaglandin biosynthesis Unsaturated liquid liquids and their
derivatives are used in
as medicinal
drugs for
prevention and treatment
atherosclerosis
(linetol - mixture
unsaturated liquid fatty acids and their
ethers) IVFA are insoluble in water, because their
molecules contain a large nonpolar
hydrocarbon radical, this part
the molecule is called hydrophobic.
O
CH3...…………(CH2)n. ………...WITH
\
ABOUT-
Non-polar “tail”
Polar head IVHs have chemical
properties of carboxylic acids,
unsaturated also
properties of alkenes Classification of saponifiable lipids
Saponifiable lipids
simple
wax
neutral
fats (triacylglycerides)
complex
phospholipids glycolipids sphingolipids Simple lipids
These include waxes, fats and oils.
Wax - esters of higher
monohydric alcohols and liquid liquids. They
insoluble in water. Synthetic
and natural waxes widely
used in everyday life, medicine,
particularly in dentistry Beeswax Myricyl Palmitate Presents
is an ester
formed by myricyl
alcohol and palmitic
acid C31H63OSOC15H31 Main component
spermaceti
Cetyl ester
palmitic acid
S16N33OSOS15N31 Wax performs protective
function, covering the surface
skin, fur, feathers, leaves and
fruits Wax coating
leaves and fruits of plants
reduces moisture loss and
reduces the possibility of infection.
Wax is widely used in
as a base for creams and ointments Neutral fats and oils
- esters of glycerol and
IVG-triacylglycerols
(triglycerides) General formula
triacylglycerols:
CH2OCOR
CHOCOR
CH2OCOR There are simple and
mixed
triacylglycerols.
Simple - contain
remnants of identical VZhK,
and mixed ones are leftovers
various acids Simple triacylglycerols
O
CH2 - O - C
C17H35
O
CH-O-C
C17H35
O
CH2 - O - C
C17H35
Tristearoyl glycerin Mixed triacylglycerols
O
CH2 - O - C
C15H31
O
CH-O-C
C17H35
O
CH2 - O - C
C17H33
1-palmitoyl-2-stearoyl-3-oleoyl
glycerol All natural fats are not
are individual
connections, and
are a mixture
various (usually
mixed)
triacylglycerols According to consistency they are distinguished:
solid fats - contain
mostly leftovers
saturated fats
of animal origin) and
liquid fats (oils)
plant origin
contain mainly
residues of unsaturated liquid fatty acids 10.3. Complex lipids
Complex lipids include
lipids having in the molecule
phosphorus, nitrogen-containing
fragments or carbohydrates
leftovers Complex lipids
Phospholipids or phosphatides derivatives of L-phosphatidic acid
acids. They are part of
brain, nervous tissue,
liver, heart. Contained in
mainly in cell membranes L-phosphatidic acid
O
O
"
R-C-O
CH2 - O - C
CH
R
O
CH2 - O - P - OH
OH General formula of phospholipids
O
O
"
R-C-O
CH2 - O - C
CH
R
O
CH2 - O - P - O-X
OH X - CH2-CH2NH2
Phosphatidyl colamine.
mullets
X-CH2-CH2-N(CH3)3
Phosphatidylcholines
lecithins
X-CH2-CH-COOH
NH2
phosphatidyl serines Cephalinas as
nitrogen-containing compounds
contain amino alcohol - colamine.
Cephalins participate in
formation of intracellular
membranes and processes,
occurring in nervous tissue Phosphatidylcholines –
(lecithins) contain
its composition is the amino alcohol choline (translated
“lecithin” - yolk). IN
position 1 (R) –
stearic or
palmitic acid, in
position 2 (R`) –
oleic, linoleic or
linolenic acid A characteristic feature of phospholipids
– amphilicity
(one end
molecules - hydrophobic, other
hydrophilic -phosphate residue with
nitrogen added to it
base: choline, colamine,
serine, etc.).
Due to
amphilicity of these lipids in an aqueous environment
form multimolecular
structures with ordered
arrangement of molecules It is this structural feature
and physicochemical properties
determine the role of phospholipids in
construction of biological
membranes
The basis of the membranes is
bimolecular lipid layer Cphingolipids
contain instead of glycerin
diatomic unsaturated
amino alcohol - sphingosine
CH3 - (CH2)12 – CH = CH - CH-CH-CH2OH
|
OH NH2 Sphingolipids include
ceramides and sphingomyelins
Ceramides - amino group in
sphingosine is acylated by VFA
CH3 - (CH2)12 - CH = CH - CH - CH - CH2OH
OH NH - C = O
R Sphingomyelins are composed of
sphingosine, acylated at
amino group of VZhK, residue
phosphoric acid and nitrous
bases (choline)
Sphingomyelins are mainly
found in animal membranes and
plant cells, especially
Nervous tissue, liver and
kidneys Glycolipids - cerebrosides and
gangliosides
include carbohydrates
residues, most often galactose
(cerebrosides) or oligosaccharides
(gangliosides), do not contain residues
phosphoric acid and related
no nitrogenous bases Cerebrosides are included in
composition of nerve sheaths
cells,
Gangliosides are found in
gray matter of the brain Glycolipids perform in
body structural
function, participate in
formation of antigenic
chemical cell markers,
regulation of normal growth
cells take part in
transport of ions through
membrane CH2OH
HO
O O - CH - CH -CH - CH = CH - (CH) - CH
2
2 12
3
OH
NHOH
OH
C=O
R
Cerebroside, R – IVZh residue 10.4. Chemical properties
saponifiable lipids
1.Hydrolysis
occurs in both acidic and
alkaline environment. Hydrolysis in
reversible in acidic environment,
catalyzed in the presence
acids Hydrolysis in alkaline medium
irreversible, received
the name "saponification" because V
as a result of hydrolysis
higher salts are formed
fatty carboxylic acids
– soaps Sodium salts are solid soaps, and potassium salts
salts - liquid soaps In vivo hydrolysis scheme
with the participation of lipase enzymes
O
CH2 - O - C
C15H31
O
CH-O-C
C17H35
O
CH2 - O - C
C17H33
+ 3 H2O
lipase a
CH2-OH
C15H31COOH
CH-OH
+ C17H35COOH
CH2-OH
C17H33COOH 2. Addition reactions
flow through double bonds
residues of unsaturated liquid fatty acids
Hydrogenation (hydrogenation)
proceeds in catalytic
conditions, with liquid oils
turn into solid fats Hydrogenation scheme
O
(CH2)7CH=CH(CH2)7CH3
0
O
tc, kt
(CH2)7CH=CH(CH2)7CH3 + 3 H2
CH-O-C
O
CH2 - O - C
(CH2)7CH=CH(CH2)7CH3
CH2 - O - C
O
CH2 - O - C
C17H35
O
CH-O-C
C17H35
O
CH2 - O - C
C17H35 Hydrogenated margarine
vegetable oil, with
adding substances
giving margarine
smell and taste Iodine addition reaction
is one of the characteristics
fat
Iodine number - number of grams
iodine, which can attach
100 grams of fat
Iodine number characterizes
degree of saturation of residues
IVF contained in fat Oils - iodine number > 70
Fats – iodine number< 703. Oxidation reactions
occur with the participation of double bonds
Oxidation by air oxygen
accompanied by hydrolysis
triacylglycerols and leads to
formation of glycerol and various
low molecular weight acids, in particular
oil, as well as aldehydes. Process
fat oxidation in air occurs
name "rancidity" Scheme of oil oxidation with oxygen
air
CH2 OCO (CH2)7CH=CH(CH2)7CH3
CHOCO (CH2)7CH=CH(CH2)7CH3
CH 2OCO (CH2)7CH=CH(CH2)7CH3
CH2-OH
+ O2 + H2O
CH-OH
CH2-OH
3 CH3(CH2)7COOH
pelargonium
+
acid
3HOOC(CH2)7COOH
azelaic
acid KMnO4 oxidation scheme
O
KMnO4
(CH2)7CH=CH(CH2)7CH3
O
+ O + H2O
(CH
CH=CH(CH
CH
CH-O-C
2 7
2 7
3
O
CH2 - O - C
(CH2)7CH=CH(CH2)7CH3
CH2 - O - C O
CH2 - O - C
CH-O-C
CH2 - O - C
OH OH
(CH 2)7CH-CH(CH 2)7CH 3
O
(CH 2)7CH-CH(CH 2)7CH 3
O
OH OH
(CH 2)7CH-CH(CH 2)7CH 3
OH OH
As a result, glycolide dihydric alcohols are formed Peroxide oxidation
lipids
reaction that occurs in
cell membranes, is
main cause of damage
cell membranes. At
lipid peroxidation
(FLOOR) atoms are affected
carbons adjacent to the double bond The LPO reaction proceeds according to
free radical chain
mechanism. Education process
hydroperoxides is
homolytic and therefore
initiated by γ-radiation. IN
in the body are initiated by HO or
HO2·, which are formed when
oxidation of Fe2+ in aqueous media
oxygen GENDER - normal physiological
process. Exceeding the norm of LPO is an indicator of pathological
processes associated with activation
homolytic transformations
Using LPO processes
explain the aging of the body,
mutagenesis, carcinogenesis, radiation
disease Peroxide oxidation scheme
fragment of unsaturated IVH
HO
RCH = CHCH2R"
RCH = CHC HR"
-H2O
O2
RCH = CHCHR"
O-O H2O
-OH
O
RCH = CH - CHR"
RCH2-C
O
+R"-C
H
HO-O
O
O
+
RCH2-C
OH
H
R"-C
OH β-oxidation
saturated acids
was first studied
in 1904
F. Knoop, who
showed that β-oxidation of fatty
acids occurs in
mitochondria Diagram of β-oxidation of fatty acids
Initially, fatty acids are activated
with the participation of ATP and KoA-SH
Acyl-CoA synthetase a
R - CH2 - CH2 - COOH
R - CH2 - CH2 - C = O
S-KoA
+HS-KoA+ATP
+ AMP + "FF" H2O
R - CH = CH - C = O
R - CH2 - CH2 - C = O
-2H
S-KoA
S-KoA
KoASH
[O]
R - CH - CH2 - C = O
OH
S-KoA
R - C - CH2 - C = O
O
S-KoA R-C=O
S-KoA
+
CH3-C=O
S-KoA
As a result of one cycle
β-oxidation of hydrocarbon chain
IVLC is shortened by 2 atoms
carbon The β-oxidation process is energetically
profitable process
As a result of β-oxidation in one
cycle produces 5 ATP molecules
Calculation of energy balance
β-oxidation of 1 molecule
palmitic acid For palmitic acid
possible 7 cycles of β-oxidation,
which results in the formation
7 x 5 = 35 ATP molecules and 8
acetyl CoA molecules
(CH3СOSKoA), which are further
are oxidized by the TCA cycle When 1 molecule of acetylCoA is oxidized, 12 molecules of ATP are released, and
when oxidizing 8 molecules - 8 x 12 =
96 ATP molecules. Therefore in
as a result of β-oxidation
palmitic acid
is formed: 35 + 96 - 1 (spent on
first stage) = 130 ATP molecules
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