Downloaded 470 times
More Related Content
Similar to Lipids properties, classification, function
More from Praveen Garg
Lipids properties, classification, function
- 1. Mrs. Praveen Garg VITSCollege, Satna
- 2. Lipids areheterogeneous group of compound related to fatty acid, fats, oils, waxes and other related substances. The term lipid was first used by German biochemist ‘Bloor’ in 1943. It is derived from a Greek word ‘lipos’ means fat. Lipids are insoluble in water and soluble in organic solvent such as benzene, ether, chloroform, acetone etc. They yield fatty acids upon hydrolysis which are utilized by living organisms. Lipids is not a polymer as like carbohydrate and proteins.
- 3. It ismacromolecules and major component of the diet because of their high energy value. The basic component of all lipid is fatty acid. The fats or lipids are defined as the esters of glycerol (alcohols) and fatty acids or as triglycerides. It is found in most plants and animals. In plants, lipids are mainly occur in seeds and fruits, whereas in animal, they are found in adipose tissue, bone marrow and nerve tissue
- 5. Triglycerides are theesters of Glycerol and Fatty acids
- 6. Glycerol ALCOHOLS: Alcohols are foundin lipid molecule may be saturated. These commonly include glycerol, cholesterol, and higher alcohol. In the structure of glycerol, the carbon atom are denoted as 1, 2, 3 from any end.
- 7. Fatty acids arelong chain organic acids having 4 to 30 carbon atoms. They have a single carboxyl group and a long, non polar hydrocarbon ‘tail’, which provide to most lipid their hydrophobic and oily nature.
- 8. Saturated fattyacids having single bond Unsaturated fatty acids having double bond Hydroxy fatty acids having hydroxyl group Cyclic fatty acids having ring structure
- 9. The generalformula of these acids is CnH2n+1COOH. They tend to be solid at room temperature. They have single bond. It may increase blood cholesterol level and cardiovascular diseases. It may be divided in two groups: Straight chain fatty acids: found in plants and animals. Example: Stearic acid- CH3(CH2)16COOH Palmitic acid- CH3(CH2)14COOH Branched chain fatty acids: minor component of natural fat or oil. Example: Isopalmitic acid- (CH3)2CH(CH2)12COOH Found in wool fat
- 10. They haveusually double bond. Unsaturated fats, which are liquid at room temperature, are beneficial fats because they can decrease blood cholesterol levels, stabilize heart rhythms, and play a number of other beneficial roles. Example: Oleic acid CnH2n-1COOH (Contain one double bond) Linoleic acid CnH2n-3COOH (Two double bond) Linolenic acid CnH2n-5COOH (Three double bond) Arachidonic acid CnH2n-7COOH (Four double bond)
- 11. CLASSIFICATION OF LIPID LIPID Simplelipid Compound lipid Derived lipid Fat & Oils Wax Phospholipids Glycolipids Steroids Terpenoid Triglycerides Beewax Lecithin Cephalins Phosphotidyl - inositol Sphingomyelins Cerebrosides Gangliosides Monoterpene Diterpenes etc Sterols
- 12. These areesters of fatty acids and alcohols. They are formed by the condensation of alcohols and acids. XH+ HOC2H5 XC2H5 + H2O ( Acid + Alcohols Ester) For example natural fats and waxes are tri-esters of fatty acids and glycerol.
- 13. Fats arefound in all living cells. They are formed from carbon, hydrogen and oxygen, but they are poor in oxygen in compare to carbohydrates. They are insoluble in water and soluble in organic solvent. The fats, which are liquid at room temperature, are called oils. Lipids are high molecular weight compounds. The glycerol is trihydric alcohols, in which one, two or three –OH group react with fatty acids to form mono, di or triglycerides.
- 14. In allfats, glycerol is present, but the composition of fatty acids may be different. The fatty acids may be saturated or unsaturated. In living cells, fat or its derivatives are present as main constituents of protoplasm. They serve as source of energy and enters in the composition of various cell components. Double energy is released from a lipid molecule than oxidation of glucose molecule. Most animal fat such as milk, meet, eggs are rich in saturated fatty acids. Plant cells contain a large portion of unsaturated fatty acids.
- 15. These arethe esters of long chain saturated and unsaturated fatty acids with monohydroxy alcohols. In vertebrates, waxes are secreted by cutaneous glands as a protective coating to keep the skin lubricated and water proof. Hair, wool and fur also coated with wax. The leaves of many plants are shiny because of the deposition of protective coating. Waxes also serve as the storage form of fuel in planktons. Waxes act as major food and storage lipid in marine organisms (whale, salmon), because they consume planktons in large amount. They are widely used in making varnishes, wax coated paper, lotion, oinments etc.
- 16. Compound lipidare those molecule which consist of glycerol and fatty acid join with other organic molecule such as carbohydrate, protein, amino acids etc. Compound lipid can be categorized in to two types: Phospholipid Glycolipid
- 17. Phospholipids area class of lipids whose molecule has a hydrophilic "head" containing a phosphate group, and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue. The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine. Phospholipids are a key component of all cell membranes. They can form lipid bilayers. The phospholipids are amphiphilic. The hydrophilic end usually contains a negatively charged phosphate group, and the hydrophobic end usually consists of two "tails" that are long fatty acid residues.
- 18. Lecithin isa fat that is essential in the cells of the body. It can be found in many foods, including soybeans and egg yolks. Lecithin is taken as a medicine and is also used in the manufacturing of medicines. Lecithin is used for treating memory disorders such as dementia and Alzheimer's disease. Lecithin is a any group of yellow-brownish fatty substances occurring in animal and plant tissues which are amphiphilic – they attract both water and fatty substances, and are used for smoothing food textures.
- 19. In additionto glycerol and 2 mol of fatty acids, lecithin also contain phosphoric acid and a nitrogen base choline. On hydrolysis, lecithin yields choline, phosphoric acid, glycerol and 2 mol of fatty acids.
- 20. Cephalins arephosphoglycerides that contain ehtanolamine or the amino acid serine attached to the phosphate group through phosphate ester bonds. Cephalins are found in most cell membranes, particularly in brain tissues. They have role in blood coagulation and accelerate blood clotting.
- 21. PI isclassified as a glycerophospholipid that contains a glycerol backbone, two non-polar fatty acid tails, a phosphate group substituted with an inositol polar head group. The most common fatty acids of phosphoinositides are stearic acid, and arachidonic acid. Hydrolysis of phosphoinositides yield one mole of glycerol, two moles of fatty acids, one mole of inositol and one, two, or three moles of phosphoric acids, depending on the number of phosphates on the inositol rings. It is regarded as the most acidic phospholipids. It play important roles in lipid signaling, cell signaling and membrane trafficking.
- 22. It isalso known as phosphosphingosides. These are commonly found in nerve tissue (myelin sheath). They are lack in plant and microorganisms. Sphingomyelin consists of a phosphocholine head group, a sphingosine, and a fatty acid. It is one of the few membrane phospholipids not synthesized from glycerol. The sphingosine and fatty acid can collectively be categorized as a ceramide. This composition allows sphingomyelin to play significant roles in signaling pathways: the degradation and synthesis of sphingomyelin produce important second messengers for signal transduction.
- 23. Glycolipids arelipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition. It is essential to the immune response and allow cells to connect to one another to form tissues. Glycolipids are found on the surface of all eukaryotic cell membranes. The essential feature of a glycolipid is the presence of a monosaccharide or oligosaccharide bound to a lipid moiety. The most common lipids in cellular membranes are glycerolipids and sphingolipids, which have glycerol or a sphingosine backbones, respectively.
- 24. Cerebrosides isthe common name for a group of glycosphingolipids called monoglycosylceramides which are important components in animal muscle and nerve cell membranes. They consist of a ceramide with a single sugar residue at the 1- hydroxyl moiety. The sugar residue can be either glucose or galactose. Therefore the two major types are called glucocerebrosides and galactocerebrosides (galactosylceramides). Galactocerebrosides are typically found in neural tissue, while glucocerebrosides are found in other tissues. Glucosylceramide is a major constituent of skin lipids, it is the only glycosphingolipid common to plants, fungi and animals. Galactosylceramides have not been found in plants.
- 25. A gangliosideis a molecule composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (e.g. n-acetylneuraminic acid, NANA) linked on the sugar chain. The name ganglioside was first applied by the German scientist Ernst Klenk in 1942 to lipids newly isolated from ganglion cells of the brain. More than 60 gangliosides are known, which differ from each other mainly in the position and number of NANA residues. It is a component of the plasma membrane that modulates cell signal transduction pathways, growth and differentiation of tissues.
- 26. Hydrolysis productof simple and compound lipids is called derived lipids. They include fatty acid, glycerol, sphingosine and steroid derivatives. Steroid derivatives are phenanthrene structures that are quite different from lipids made up of fatty acids.
- 27. Steroids arederived lipids because they are hydrophobic and insoluble in water, but they do not resemble lipids since they have a structure composed of four fused rings. Sterols such as cholesterol and ergosterols is the most common steroid and is the precursor to vitamin D, estrogen, progesterone, aldosterone, cortisol, and bile salts. Sterols also known as steroid alcohols. Sterols of plants are called phytosterols and sterols of animal are called zoosterols. Cholesterol is common zoosterols and stigmasterol is phytosterols. Ergosterols is present in cell membrane of fungi and protozoa.
- 28. Cholesterol iswidely distributed in all cells and is a major component of cell membrane and lipoproteins. Cholesterol is a C27 compound with molecular formula C27H46O. With a hydroxyl group at C3 and a double bond between C5 and C6. An aliphatic side chain is attached at C17 and 5 methyl groups. Cholesterol exists as crystals that are white, shiny. It has a high melting point of 150ºC. It is insoluble in water and soluble in fat solvents. Cholesterol oxidized under suitable conditions and to form a ketone called cholestenone. The hydroxyl group of cholesterol readily forms ester with fatty acids like stearic acid.
- 29. It helps inmaintenance of our body temperature and protects our internal organs. In pharmaceutical industries, cholesterol is used in the manufacture of steroid hormones and vitamin D.
- 30. The terpenoids,sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene, and the isoprene polymers called terpenes. Most are multicyclic structures with oxygen-containing functional groups. Terpenoids mostly occur in natural products and can be found in all classes of living things. Several terpenoids are biologically active and are exploited in the fight against cancer, malaria, inflammation, and a variety of infectious diseases. Terpenoids can be classify as monoterpene, diterpene, and polyterpene etc. Most common example are carotenoids, lycopene pigment etc.
- 31. Lipids maybe either liquids or non-crystalline solids at room temperature. Pure fats and oils are colorless, odorless, and tasteless. They are energy-rich organic molecules. Insoluble in water. Soluble in organic solvents like alcohol, chloroform, acetone, benzene, etc. No ionic charges. Solid triglycerols (Fats) have high proportions of saturated fatty acids. Liquid triglycerols (Oils) have high proportions of unsaturated fatty acids. Physical property:
- 32. 1. Hydrolysis oftriglycerols: Triglycerols like any other esters react with water to form their carboxylic acid and alcohol a process known as hydrolysis.
- 33. 2. Saponification: Triacylglycerolsmay be hydrolyzed by several procedures, the most common of which utilizes alkali or enzymes called lipases. Alkaline hydrolysis is termed saponification because one of the products of the hydrolysis is a soap, generally sodium or potassium salts of fatty acids.
- 34. 3. Hydrogenation: Thecarbon-carbon double bonds in unsaturated fatty acids can be hydrogenated by reacting with hydrogen to produce saturated fatty acids.
- 35. 4. Halogenation: Unsaturatedfatty acids, whether they are free or combined as esters in fats and oils, react with halogens by addition at the double bond(s). The reaction results in the decolorization of the halogen solution. Stearate tetra iodinate
- 36. Lipids playextremely important roles in the normal functions and structure of a cell membrane. It is used as energy storage and work as insulator. Used as a protective coating in plant leaves from drying up. Lipid act as hormones. Act as the structural component of the body and provide the hydrophobic barrier. Lipids are major sources of energy in animals and high lipid containing seeds. Lipid act as chemical messengers between cells. Layers of subcutaneous fat under the skin also help in insulation and protection from cold.
- 37.