Material : Lipids Lipids are biological compounds that consist mostly or entirely of non-polar groups, meaning that fats are soluble in non-polar solvents and relatively insoluble in water. Fat can be extracted from iving matter using non-polar solvents such as petroleum ether, ethyl ether, benzene and chloroform into a fat fraction consisting of edible fat, wax, phospholipids, sterols, hydrocarbons and pigments. The components of the fat fraction can be differentiated using NaOH. Fat/oil, wax and phospholipids can be used saponified with NaOH, while sterols, hydrocarbons and pigments are unsaponifiable fraction. Almost all foodstuffs contain a lot of fat, especially foods that come from animals. Fat in animal tissue is found in adipose tissue. In plants, fats are synthesized from one glycerol molecule with three fatty acid molecules which are formed from the continued oxidation of carbohydrates in the respiration process. Classification and Structure of Lipids Fats can be classified into two groups, in various ways. Based on animal and source fats, fats are classified as vegetable fats. Animal fats contain lots of sterols called cholesterol, while vegetable fats contain phytosterols and more contains many unsaturated fatty acids, so it is generally in the form of liquid. Based on their consistency, fats can be classified as fats solid (salt) and liquid fat (oil). Solid fats usually come from land animals such as milk fat, pork fat, beef fat. Solid fats derived from vegetable fats, for example cocoa butter and the "stearin" part of Palm oil. Liquid fat that comes from marine animals, for example whale oil, cod liver oil, herring oil. Liquid fat from Vegetable fats can also be divided into three groups, namely:  drying oil, which will form a hard layer when it dries in air, for example oil that can be used for paint and varnish;  semi drying oil, for example corn oil, sunflower seed oil; and  non drying oil, for example coconut oil and peanut oil. Based on its form, fat is classified as hidden fat, for example fat contained in ingredients foods such as meat, fish, eggs, milk, avocados, peanuts and several types of vegetables. Meanwhile, fat that has been extracted from animals or plants and purified is known as visible fat. Based on their chemical structure, fats can be classified as:  single fats such as fats and oils, waxes, sterol esters;  Fat compound Lipid Structure 1. Based on their chemical structure, lipids are glyceride esters with more than 10 atoms which are formed from the esterification reaction between fatty acids and glycerol. In addition, glyceride esters form fats and oils. The structure of fatty acids and glycerol in lipid compounds is as follows: O H2C OH II HC OH R C OH H2C OH 2. Based on the structure of triglycerides, lipids are divided into two types, namely fats and oils. Fats and oils are classified as triglyceride compounds or triacylglycerol which means a compound that has 3 glycerols. The three OHs of glycerol can be changed with a type of acid residue or various types of acid residue. Function and Role of Lipids In general, it can be said that fat fulfills a basic function for humans, namely: Being an energy reserve in the form of fat cells. 1 grams of fat produces 39.06 kjoules or 9.3 kcal.  Fat has cellular functions and structural components cell membranes that are connected to carbohydrates and proteins to carry out the flow of water, ions and other molecules, in and out of the cell.  Supports the function of organic compounds as signal conductors, such as on prostaglandins and steroid hormones and bile glands, becomes a suspension for vitamins A, D, E and K which are useful for the process biological  Functions as a shock absorber to protect vital organs and protects the body from unpleasant external temperatures.  Fat is also a means of circulating energy in the body and the main component that forms the membrane of all types of cells.  Membrane structural components. All cell membranes include myelin contains a double lipid layer. Membrane functions include: as a permeable barrier  Protective coating on some bodies. The function of membranes which contain mostly lipids is like a permeable barrier for prevents infection and excessive loss or addition of water. Forms energy reserves, as the main function of triacylglycerol found in adipose tissue.  Enzyme cofactors/precursors function for enzyme activity such as phospholipids in the blood, coenzyme A, and so on.  Hormones and vitamins, prostaglandins where arachidonic acid is a precursor for the biosynthesis of prostaglandins, steroid hormones, etc.  Barrier Insulation, to avoid heat, electrical and physical stress. Sources of Lipids Lipids or fats come from animals and plants, if they come from animals they are called animal fats, whereas if they come from food they are called vegetable fats.Examples of animal fats are fats from chicken, beef, eggs and fish. Examples of vegetable fats are avocado, nuts and coconut oil. Classification of Lipids 1. Fatty Acids Fatty acids are long chain monocarboxylic acids. The general formula for fatty acids is: CH3(CH2)nCOOH or CnH2n+1-COOH It is the defining constituent of lipids and is largely responsible for their characteristic physical and metabolic properties. They also important in the free form of Crocetin. In the body it is released from triacylglycerol during fasting to provide a source of energy. Linoleic and linolenic acids are essential fatty acids, in that they cannot synthesized by animals and must come from plants through the diet. They are precursors of arachidonic, eicosapentaenoic and docosahexaenoic acids, which is an important component of all lipid membranes. There are two Types of fatty acids are:  Saturated Fatty Acids Saturated fatty acids are fatty acids that contain single bonds in their hydrocarbon chains. Saturated fatty acids have zig-zig chains that can fit together, so the Vanderwalls attraction force is high, so they are usually solid.  Unsaturated fatty acids Unsaturated fatty acids are fatty acids that contain one double bond in their hydrocarbon chain. Fatty acids with more than one double bond are not common, especially found in oils vegetable oils, these oils are called polyunsaturated. Polyunsaturated triglycerides (polyunsaturates) tend to be in the form of oil. 2. Glycerides  Neutral glycerides (neutral fat) Neutral glycerides are esters between fatty acids and glycerol. The basic function of neutral glycerides is as energy storage (in the form of fat or oil). Each glycerol may be bound to 1, 2 or 3 fatty acids which do not have to be the same. If glycerol binds to 1 acid Fats are called monoglycerides, if they are linked to 2 fatty acids they are called diglycerides and if they are linked to 3 fatty acids they are called triglycerides. Triglycerides are an important energy reserve from lipid sources.  Phosphoglycerides (phospholipids) Lipids can contain phosphate groups. Fats are modified when phosphate replaces one of the fatty acid chains. The use of phosphoglycerides is as a component of cell membranes and as an emulsifier. Phospholipid bilayer (double layer) is a constituent of cell membranes. 3. Non-Glyceride This type of lipid does not contain glycerol. So the fatty acids combine with non-glycerol molecules. Which is included in this type are sphingolipids, steroids, cholesterol, steroids, androgens, estrogens.  Sphingolipids Cyphongolipids are phospholipids that are not derived from fat. The primary use of sphingolipids is as a constituent of the myelin sheath of nerve fibers. In humans, 25% of lipids is a sphingolipid.  Cholesterol Apart from phospholipids, cholesterol is a type of lipid that makes up the plasma membrane. Cholesterol is also part of some hormones. Cholesterol is associated with hardening of the arteries. In this case, plaque forms on the artery walls, which results in increased blood pressure due to narrowed arteries, decreased ability to stretch. Clot formation can occur causes myocardial infarction and stroke.  Steroids Some reproductive hormones are steroids, for example androgens and estrogens. Another steroid is cortisone. This hormone is related to the process of carbohydrate metabolism, handling rheumatoid arthritis, asthma, digestive disorders and etc.  Androgens Androgen is a generic term for natural or synthetic compounds, usually steroid hormones, that stimulate or controls the development and maintenance of the masculine characteristics of vertebrates to bind to androgen receptors. This including the activity of male and accessory sexual organs development of secondary sex characteristics.  Estrogen Estrogens (or oestrogens) are a group of steroid compounds that function primarily as female sex hormones. Although found in both men and women's bodies, the content is far away higher in the bodies of women of childbearing age. 4. Complex Lipids  Lipoproteins Lipids are insoluble in water, and so lipids can be transported in the flow In blood, lipids must associate with proteins to form bonds macromolecules called lipoproteins. The LPP complex in the blood is called a lipoprotein particle which functions as a means of transporting lipids in the blood. Compounds that include lipids are cholesterol (Col), cholesterol esters (KolE), phospholipids (FL), triglycerides and fatty acids. All plasma lipids in humans are transported in the blood as LPP, except acids a fat in the blood that is primarily bound to albumin. The Types of Lipoproteins: 1) Kilimicrons. Chylomicrons (chylomicrons) are low density lipoproteins most contain TG originating from food (exogenous fat). Chylomicrons produced in the intestine enter the systemic circulationthrough lymphatic channels; The triglycerides are hydrolyzed by lipoprotein lipase,an enzyme located on the endothelial surface of capillary blood vessels. 2) Very Low-Density Lipoprotein (VLDL). VLDL is the second lowest density lipoprotein group and is synonymous with pre-betaliporotein. VLDL mainly comes from the liver and has the function of transporting triglycerides made in tissues. 3) Low-Density Lipoprotein (LDL). LDL cholesterol is the main means of cholesterol transport which accounts for around 70-80% of total cholesterol from the liver to peripheral tissues. LDL cholesterol holds cholesterol and apoprotein B-100 which generally comes from VLDL so that LDL is rich in cholesterol and apoprotein B-100. 4) High Density Lipoprotein (HDL). HDL functions as a carrier of cholesterol from peripheral tissues to liver for metabolism (catabolism) which is then excreted from the body. Very high HDL levels (up to 95%) are positively correlated with length of life. 5. Glycolipids Glycolipids are lipid molecules that contain carbohydrates, usually simple ones such as galactose or glucose. Will but the term glycolipid is usually used for lipids contains sugar units but does not contain phosphorus. Glycolipids can be derived from glycerol or pingosine and are often edible glycerides or as sphingolipids. Lipid Identification Reactions Lipid Identification Reactions There are three types of chemical reactions that occur in lipids, namely reactions formation (hydrolysis), saponification reaction (saponification), and reaction hydrogenation.  Formation Reaction (Hydrolysis) The formation reaction - hydrolysis are two mutual reactions the opposite.  Saponification / Condensation Reaction The saponification/saponification reaction is a mixture of fat and base strong which produces soap (fat salt) with glycerol.  Hydrogenation Reaction The hydrogenation reaction is a fat saturation reaction converts fat into solid form. SUMMARY 1. 2. 3. In general it can be said that fats fulfill basic functions for humans, namely: As an energy reserve in the form of fat cells, as a cellular function and a structural component of cell membranes which are related to carbohydrates and proteins to carry out the flow of water, ions and other molecules, in and out of cells, support the function of organic compounds as signal conductors, become suspensions for vitamins A, D, E and K which are useful for biological processes, as shock absorbers to protect vital organs and protects the body from unpleasant external temperatures. Classification of Lipids according to Bloor, divided into two. First is Lipids simple consisting of neutral lipids (function as energy stores), wax (often used as a protective layer for the skin and hair). Second, compound lipids consist of phospholipids (functions to form the framework of brain cells), Fatty Acids (as building blocks of body fat), Cholesterol (as the main component of membranes brain and nerve cells). Classification of lipids based on their origin, namely vegetable fats (function reduces cholesterol levels) and animal fats (functions to facilitate the digestive process). Classification of Lipids based on their bonds, namely Fats and Oils which function as one a constituent of cell walls and biomolecular materials. Lipid Classification based on the class of fat, namely fatty acids (function as building blocks of body fat), neutral glycerides (as energy stores), phospholipids (emulsifier lipids in the digestive tract), Sphingolipids (as components of the myelin sheath of nerve fibers), Steroids (function as hormones).