Phospholipid-derived fatty acids (PLFA) are widely used in microbial ecology as chemotaxonomic markers of bacteria and other organisms.
1. Omega-3 Essential Fatty Acids. Omega-3 essential fatty acids are necessary within the human body, but they can also be produced modestly within the body. However, you need to be sure that enough Omega-3 is in your diet. Omega-3 serves a variety of purposes within the body.  Omega-6 Fatty Acids. Omega-6 fats are derived from linoleic acid and are found in leafy vegetables, seeds, nuts, grains, and vegetable oils (corn, safflower, soybean, cottonseed, sesame, sunflower). The principal omega-3 is alpha-linolenic acid (ALA), which is then converted into eicosapentaenoic acid (EPA) and docosahexaenonic acid (DHA) by the body. This makes ALA the only essential omega-3 fatty acid. ALA can be found in many vegetables, beans, nuts, seeds, and fruits. Allergies. Avoid fish-derived omega-3 supplements if allergic or sensitive to fish, fish oil, or omega-3 fatty acid products derived from fish. Avoid plant-derived omega-3 supplements if allergic or sensitive to nuts, seeds, or plants from which they are derived. Skin rash and allergic response have been reported Phospholipid-derived fatty acids (PLFA) are widely used in microbial ecology as chemotaxonomic markers of bacteria and other organisms. Phospholipids are the primary lipids composing cellular membranes. Phospholipids can be saponified, which releases the fatty acids contained in their diglyceride tail. Each phospholipid consists of a polar hydrophilic head (red) and two hydrophobic fatty acid tails. The fatty acid structure affects the bilayer structure. Fatty acids with an unsaturated tail (blue) disrupt the packing of those with only saturated tails (black). In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with a long aliphatic tail (chain), which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 12 to 28. Fatty acids are usually derived from triglycerides or phospholipids. When they are not attached to other molecules, they are known as free fatty acids. Fatty acids are important sources of fuel because, when metabolized, they yield large quantities of ATP. Thus, saturated fatty acids are saturated with hydrogen (since double bonds reduce the number of hydrogens on each carbon). Because saturated fatty acids have only single bonds, each carbon atom within the chain has 2 hydrogen atoms (except for the omega carbon at the end that has 3 hydrogens). The nomenclature of a fatty acid is derived from the name of its parent hydrocarbon by substituting the final e with an oic (i.e., the C 18 saturated fatty acid is called octadecanoic acid because its parent hydrocarbon is called octadecane). In nature, most fatty acids exist as straight-chain hydrocarbons that attach to a carboxylic acid with the most frequent and even number of carbon atoms. The chain-length range is from 2 to 80 but commonly from 12 up to 24. Good fats consist of poly and monounsaturated fatty acids. Foods such as olive oil, soybean oil, and other vegetable derived oils are usually included. For example Butter consists of 29% Palmitic acid, 9% Stearic acid, 27% Oleic acid, 4% Linoleic acid, and 31% other. While olive oil consists of 6% Palmitic, 4% Stearic, 83% Oleic, and 7% linoleic fatty acids. In nature, most fatty acids exist as straight-chain hydrocarbons that attach to a carboxylic acid with the most frequent and even number of carbon atoms. The chain-length range is from 2 to 80 but commonly from 12 up to 24. Other fatty acids such as omega-3 fatty acids can be produced by the body, but it is easier to get these from diet. Some sources are fish oils. These fatty acids are used to help with essential body functions such as blood clotting, immune response, or blood pressure. In nature, most fatty acids exist as straight-chain hydrocarbons that attach to a carboxylic acid with the most frequent and even number of carbon atoms. The chain-length range is from 2 to 80 but commonly from 12 up to 24. Omega-3 fatty acids are derived from linolenic acid. The principal omega-3 is alpha-linolenic acid (ALA), which is then converted into eicosapentaenoic acid (EPA) and docosahexaenonic acid (DHA) by the body. This makes ALA the only essential omega-3 fatty acid. ALA can be found in many vegetables, beans, nuts, seeds, and fruits.
http://www.fitday.com/fitness-articles/nutrition/fats/what-are-essential-fatty-acids.html http://www.pcrm.org/health/health-topics/essential-fatty-acids http://www.mayoclinic.org/drugs-supplements/omega-3-fatty-acids-fish-oil-alpha-linolenic-acid/safety/HRB-20059372 https://en.wikipedia.org/wiki/Phospholipid-derived_fatty_acids https://en.wikipedia.org/wiki/Fatty_acid https://en.wikibooks.org/wiki/Structural_Biochemistry/Lipids/Fatty_Acids https://en.wikibooks.org/wiki/Structural_Biochemistry/Lipids/Fatty_Acids https://en.wikibooks.org/wiki/Structural_Biochemistry/Lipids/Fatty_Acids http://www.pcrm.org/health/health-topics/essential-fatty-acids
where are fatty acids derived from