Online Counseling Resource YCMOU ELearning Drive…

1. Online Counseling ResourceYCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan MaharashtraOpen University, Nashik – 422222, India

2. OC-SBT/ SBI/ SGS031-U02-02Introduction Programmes and Courses SEP –SBT031- Unit 02 SEP – SBI031 – Unit 02 SEP – SGS031 – Unit 02

3. Credits • Academic Inputs by • Mrs.Rasika Bhore • M.sc (Microbiology) • rasika.bhore@gmail.com © 2007, YCMOU. All Rights Reserved.

4. How to Use This Resource • Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling. • Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes. • Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student. • Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam. • Appear several times, for all the Self-Tests, available for this course. • Student can use handouts for last minutes preparation just before end exam. © 2007, YCMOU. All Rights Reserved.

5. Learning Objectives • After studying this module, you should be able to: • Discuss the triglycerides with their structure & function. • Describe physical properties & uses of oils & fats. • Describe the types of waxes & its sources. • Define phospholipids , glycolipids. • Discuss various phospholipids such as gangliosides, plasmologens, sphingolipids with their structures & functions. • Describe the disorders cause due to excess or depletion or failure metabolism of all these lipids. © 2007, YCMOU. All Rights Reserved.

6. Introduction • Glycerides with three acyl groups that are triglycerides or neutralfats are the main form of fatty energy storage in animals and plants. • Vegetable fats and oils are substances derived from plants that are composed of triglycerides. • Waxes are esters of fatty acids with higher molecular weight monohydric long chain alcohols. • Waxes have no importance as far as human metabolism is concerned but they are widespread in nature. • Phospholipids having hydrophobic & hydrophilic ends. There types are- Plasmologens, sphingophospholipid. • Gangliosides are glycoproteins, carry out many important functions in immune system. © 2007, YCMOU. All Rights Reserved.

7. Triglycerides or Neutral Fats • These are esters of fatty acids with glycerol. • As they are uncharged, named as neutral fats. • These are composed of three fatty acids, which are esterified through their carboxyl groups, resulting in a loss of negative charge & formation of neutral fat. • The fat we eat are mostly triglycerides. • Triglycerols containing the same kind of fatty acids in all three positions are called simple triacylglycerols. • Mixed triacylglycerols contain two or more different fatty acids. • Fatty acid on C-1 is usually saturated,C-2 is unsaturated, & C-3 can be either. • Presence of unsaturated fatty acid decreases the melting point of lipid & remains in liquid form. • As the polarhydroxyl groups of glycerol & polar carboxyl groups of the fatty acids are bound in ester linkages, triacylglycerols are non-polar, hydrophobic, neutral & essentially insoluble in water. © 2007, YCMOU. All Rights Reserved.

8. Structure of Triacylglycerol • Hydrogenion of the fatty acid combines with the hydroxyl group of the glycerol, forming a triacylglycerols with release of water molecule. GlycerolFatty acids triacylglycerol © 2007, YCMOU. All Rights Reserved.

9. Occurrence of Triglycerides • In many foods. • Vegetable oils such as olive oil, corn oil. • Plants, such as the avocado, the palm, the fruit also contains large amounts of triglycerides. • Dairy products. • They are also present in blood plasma that derived from fats eaten in foods or made in the body from carbohydrates. • Calories ingested in a meal and not used immediately by tissues are converted to triglycerides and transported to fat cells to be stored. © 2007, YCMOU. All Rights Reserved.

10. Functions of Triglycerides • Triglycerides contribute to the structure of membranes by the formation of a lipid bilayer. • The main biological function of triglycerides is as a fuel. • Provide much of the energy needed for cells to function. • Plants store energy in fats and oils. Oils are particularly common in seeds, where the stored energy helps seedlings during germination, until they can exploit solar energy through photosynthesis. • Fat serves as a protective cushion and provides structural support to help prevent injury to vital organs such as the heart, liver, kidneys, and spleen. © 2007, YCMOU. All Rights Reserved.

11. Be Aware……….. • Abnormally high levels of triglycerides and cholesterol are thought to be involved in hardening of the arteries. • Lipids may be deposited on the walls of arteries as a partial consequence of their insolubility in the blood. • High triglyceride levels have been associated with heart disease. © 2007, YCMOU. All Rights Reserved.

12. Oils & Fats • Vegetable fats and oils are substances derived from plants that are composed of triglycerides. • Triglyceride-based vegetable fats and oils can be transformed through partial or complete hydrogenation into fats and oils of higher melting point. • Oils are liquid at room temperature, and fats are solid; a dense brittle fat is called a wax. • Although many different parts of plants may yield oil, actually oil is extracted primarily from the seeds of oilseed plants. © 2007, YCMOU. All Rights Reserved.

13. Structure of Oils & Fats © 2007, YCMOU. All Rights Reserved.

14. Physical Properties of Oils & Fats • State:- fats containing saturated fatty acids are solid at room temperature, e.g. animal fats .The plant fats posses unsaturated fatty acids therefore liquid at room temperature. • Color, odor & taste:- when the fats are in pure state, they are colorless, odorless & have extremely bland taste. But they are capable of absorbing odors. • Solubility:- fats are only sparingly soluble in water, while freely soluble in organic solvents. This solubility decreases with the increase in chain length. Addition of hydroxyl group increases solubility. • Melting point:- Melting point of fatty acids depends on the chainlength & degree of unsaturation. Higher the double bonds, lower the melting point. • Specific gravity:- specific gravity of fats is less than 1,so, they float on water. Increase in unsaturation & length of chain, increases the specific gravity. © 2007, YCMOU. All Rights Reserved.

15. Physical Properties of Oils & Fats 6.Geometric isomerism:- presence of double bond in unsaturated fatty acids produces Cis-trans isomerism. • Insulation:- fats are bad conductor of heat; that means have high insulating power. In warm blooded animals layers of fat under skin act as a blanket. • Emulsification:- emulsifiers such as soaps, gums convert the lipid mass in to small lipid droplets, called emulsification. Fats have to be emulsified before they can absorbed by intestinal wall. • Surface tension:- it is the force which held together the surface molecules. When liquid fat is poured on water, it reduces surface tension of water by forming unimolecular layer on water surface. © 2007, YCMOU. All Rights Reserved.

16. Chemical Properties of Fats • Hydrolysis:- fats are hydrolyzed by the enzyme lipase to yield fatty acids & glycerol. • Reaction carried out at alkaline pH 7.5-8.5. • The fats first splits to produce diglycerides, then monoglycerides & finally to fatty acid & glycerol. 2. Saponification:- hydrolysis of fats by alkali is called Saponification. • Products of saponification are glycerol & salts of fatty acids called soaps. • Soaps are of 2 types:- hard soaps & soft soaps. • Hard soaps are sodium salts of higher fatty acids while soft soaps are potassium salts. • Fatty acid salts of calcium, zinc, magnesium & lead are insoluble in water. © 2007, YCMOU. All Rights Reserved.

17. Uses of Oils • Inedible vegetable fats and oils such as linseed oil, tung oil, and castor oil, used in lubricants, paints, cosmetics, pharmaceuticals, and other industrial purposes. • Many vegetable oils are used directly as ingredients in food, example including butter and ghee. • The oils serve a number of purposes in this role: • Texture:- oils can serve to make other ingredients to stick together. • Flavor:- oils such as almond oil, olive oil may be choosen for flavor impact. • Many vegetable oils are used to make soaps, skin products, perfumes and other personal care and cosmetic products. • Some oils are particularly suitable as drying agents, and are used in making paints and other wood treatment products. • Vegetable oils are also used to make biodiesel, which can be used like conventional diesel. © 2007, YCMOU. All Rights Reserved.

18. Waxes • Waxes are esters of fatty acids with higher molecular weight monohydric long chain alcohols. • In addition to beeswax, carnauba (a plant epicuticular wax), paraffin (a petroleum wax) are commonly encountered waxes which occur naturally. • Earwax is an oily substance found in the human ear. Some artificial materials that exhibit similar properties are also described as wax or waxy. • Waxes can be divided into four types: • Animal & insect waxes • Vegetable waxes • Mineral waxes • Synthetic waxes © 2007, YCMOU. All Rights Reserved.

19. Animal & Insect’s Waxes Beeswax - produced by honey bees. Chinese wax - produced by scale insects Coccus ceriferus. Shellac wax - from the lac insect Coccus laca. Spermaceti - from the head cavities and blubber of the sperm whale. Lanolin (wool wax) - from the sebaceous glands of sheep. © 2007, YCMOU. All Rights Reserved.

20. Vegetable Waxes Bayberry wax - from the surface of the berries of the bayberry shrub. Candelilla wax - from the Mexican shrubs. Carnauba wax - from the leaves of the Carnauba palm. Castor wax - catalytically hydrogenated castor oil. Esparto wax - a byproduct of making paper from esparto grass. Japan wax - a vegetable triglyceride (not a true wax), from the berries of Rhus and Toxicodendron species. Jojoba oil - jojoba is pressed from the seeds of the jojoba bush. Ouricury wax - from the Brazilian Feather palm. Rice bran wax - obtained from rice bran (Oryza sativa). © 2007, YCMOU. All Rights Reserved.

21. Mineral Waxes & Synthetic Waxes • Ceresin waxes • Montan wax - extracted from lignite and brown coal. • Ozocerite - found in lignite beds. • Peat waxes • Polyethylene waxes - based on polyethylene • Fischer-Tropschwaxes • Chemically modified waxes - usually esterified or saponified • Substituted amide waxes • polymerized α-olefins r unsaturated fatty acids. © 2007, YCMOU. All Rights Reserved.

22. Phospholipids • Phospholipids are fatderivatives in which one fatty acid has been replaced by a phosphate group and one of several nitrogen-containing molecules. • It consists of a hydrophilic polar head group and a hydrophobic tail.  • The polar head group contains one or more phosphategroups.  The hydrophobic tail is made up of two fattyacylchains. • When many phospholipid molecules are placed in water, their hydrophilic heads tend to face water and the hydrophobic tails are forced to stick together, forming a bilayer. • They are major lipid constituents of cellular membranes. • Comprises about 40% in erythrocytic membrane & over 95% in inner mitochondrial membrane. © 2007, YCMOU. All Rights Reserved.

23. Structure of Phospholipids • In the example below the phosphate group is ionic and therefore hydrophilic (orange). The fatty acid side groups are hydrophobic (blue). © 2007, YCMOU. All Rights Reserved.

24. Classification of Phospholipids • There are two classes of phospholipids: those that have a glycerol backbone and those that contain sphingosines. • Both classes are present in the biological membrane. • Phospholipids that contain a glycerol backbone are called phosphoglycerides (or glycerophospholipids), which are the most abundant class of phospholipid found in nature. • Types of naturally occurring phosphoglycerides are: • Phosphatidylcholine (lecithin) • Phosphatidylethanolamine (cephalin) • Phosphatidylserine • Phosphatidylinositol • Plasmolagens and • Cardiolipin • The structural diversity is dueto the variability of the chain length and degree of saturation of the fatty acid ester groups. © 2007, YCMOU. All Rights Reserved.

25. Plasmologens • Plasmologens are generally similar to other phospholipids but the fatty acid chain at C1 of glycerol is linked through an ether bond. • There are three major classes of plasmologens: • Phosphatidalcholines • Phosphatidalethanolamines • Phosphatidalserines • These are found in myelin & in cardiac muscle. • Myelin contains ethanolamine plasmologens. • Heart muscles contains choline plasmologens. • Platelet activating factor (PAF) is plasmologens & involved in platelet aggregation & degranulation. © 2007, YCMOU. All Rights Reserved.

26. Sphingophospholipids • Sphingomyelin is the major sphingosine containing phospholipid. • The backbone of sphingomyelin is sphingosine, an amino alcohol formed from palmitate and serine. • The amino terminal is acylated with a long-chain acyl CoA to yield ceramide. Subsequent substitution of the terminal hydroxyl group by phosphatidyl choline forms sphingomyelin. • Sphingomyelinase, a lysosomal enzyme, hydrolytically degradessphingomyelin. • A genetic disorder caused by a defect in the production of sphingomyelinase, called Niemann-Pick disease. © 2007, YCMOU. All Rights Reserved.

27. Functions of Sphingolipids • Sphingolipids protect the cell surface against harmful environmental factors by forming a mechanically stable and chemically resistant outer leaflet of the plasma membrane lipid bilayer. • Certain complex glycosphingolipids were found to be involved in specific functions, such as cell recognition and signaling. • Simple sphingolipid metabolites, such as ceramide and sphingosine-1-phosphate, have been shown to be important mediators in the signaling cascades involved in apoptosis, proliferation, and stressresponses. • In the plasma membrane and in endosomes, they perform many of their functions, thus travelling and evolving between organelles. • Clinically important classes of sphingolipids are those that confer antigenic determinants on the surfaces of erythrocytes. © 2007, YCMOU. All Rights Reserved.

28. Gangliosides • Gangliosides are the group of glycosphingolipids that show the greateststructural variation and also the more complex structure. • This group includes molecules composed of ceramide linked by a glycosidic bond to an oligosaccharide chain containing hexose and N-acetylneuraminic acid (NANA, acidic sugar known also as sialic acid) units. • These glycosphingolipids were discovered in brain and named by ErnstKlenk . • They account for about 6% of the lipid weight. • The 40+ known gangliosides differ mainly in the position and number of NANA residues. © 2007, YCMOU. All Rights Reserved.

29. Common Gangliosides • Some of the common gangliosides are: • GD1a • GD1b • GD2 • GD3 • GM1 • GM2 • GM3 • GT1b © 2007, YCMOU. All Rights Reserved.

30. Functions of Gangliosides • Gangliosides are functional ligands for maintenance of myelinstability and the control of nerve regeneration. • Occurrence of gangliosides in cell nuclei suggests a possible involvement of gangliosides in the expression of genes relevant to neuronal function. • They have key functions in the immune defense systems. • They act as receptors of interferon, epidermal growth factor, nerve growth factor and insulin and in this way may regulate cell signaling. • Gangliosides bind specifically to viruses and to various bacterial toxins, such as those from botulinum, tetanus and cholera, and they mediate interactions between microbes and host cells during infections. • The best known example is cholera toxin, which is an enterotoxin produced by Vibrio cholerae; its specific cell surface receptor is gangliosides GM1. © 2007, YCMOU. All Rights Reserved.

31. Disorders of Gangliosides • Storage of excessive amounts of gangliosides GM1 in the nerve cells in the brain and other tissues, because of failures in the catabolic mechanism, is Tay-Sachs disease, a fatal genetic disorder. • Thus the nerve cells become distended and a relentless deterioration of mental and physical abilities occurs. • This condition is caused by insufficient activity of a specific enzyme, β-N-acetylhexosaminidase, which catalyses the biodegradation of gangliosides. • A generalized gangliosidosis has been characterized in which ganglioside GM1accumulates in the nervous system leading to mentalretardation and enlargement of the liver. • Impairedganglioside metabolism may also be relevant to Alzheimer’s disease and Parkinson’s disease. © 2007, YCMOU. All Rights Reserved.

32. What we learn……… • Triglycerides are fatty acids with glycerol in which are esterified by carboxyl groups, thus uncharged. • The fats & oils we eat are almost triglycerides. • Triglycerides act as fuel & contribute as structural component. • Physical & Chemical properties of oils & fats. • Animal waxes, vegetable waxes, mineral waxes & synthetic waxes are the 4 types of waxes. • Phospholipids such as plasmologens are found in myelin & heart muscles. • Sphingolipids plays very important role of protection of cell surface & also in cell signaling & antigenic determinants. • Gangliosides are complex molecules acts actively in immune system. © 2007, YCMOU. All Rights Reserved.

33. Critical Thinking Questions • Why some fats are liquid while others are solid at room temperature? • Why the elevation in the level of gangliosides occurs? • If we increase the chain of fatty acids by adding double bonds, will it float on water? © 2007, YCMOU. All Rights Reserved.

34. Hints for critical thinking questions • See physical properties if oils & fats. • An enzyme regulates the degradation of gangliosides. • Specific gravity of oils & fats. © 2007, YCMOU. All Rights Reserved.

35. Book Title: Principles of Biochemistry Author: David Nelson & Michael Cox Study Tips • Book • Title: Biochemistry • Author: Donald Voet & Judith Voet © 2007, YCMOU. All Rights Reserved.

36. Study Tips www.en.wikipedia.org Phospholipids. Vegetable fats & oils. Sphingolipids. www.betterhealth.gov Fats & oils better health channel www.biology.clc.edu Lipids © 2007, YCMOU. All Rights Reserved.

37. Acknowledgments • www.tshc.fsu.edu • www.academic.brooklyn.edu • www.web.books.com © 2007, YCMOU. All Rights Reserved.

38. End of the Presentation Thank You