Fatty acids hydrocarbon chains

Structure of a neutral glycosphingolipid, galactocerebroside (R is a fatty acid hydrocarbon chain). 

Interferes with the orderly alignment of fatty acid hydrocarbon chains in membranes... 

Acyl groups with fatty acid hydrocarbon chains... 

Fixed oils are composed of fatty acids, hydrocarbon chains with a methyl (CH3) gronp at one end (Cl end), and a carboxyl gronp (COOH) at the other (8 end). The hydrocarbon chains may be np to 24 carbon atoms long. 

Biosynthesis of Esters. Fatty acids are naturally occurring, long, straight-chain, C12-C40 carboxylic acids most contain an even number of carbon atoms.Their biosynthesis provides an important and interesting example of a primary metabolic pathway in which a special type of ester is the essential link between the enzyme and the substrate (acetic acid).The enzyme-bound substrate grows by repeated addition of two-carbon (C2) units and, when eventually released from the enzyme, has undergone an extension of the fatty acid hydrocarbon chain. 

Free Liberated. In the case of triglycerides, meaning the fatty acid hydrocarbon chains are detached from glycerol, and thereby become free fatty acids. 

Oxidation reactions of the fatty acid hydrocarbon chains are common to free fatty acids and their esters, such as triacylglycerols. Carboxyl groups of free fatty acids, however, accelerate the decomposition of fatty acid hydroperoxides and can react with some oxidation products. In foods, the following types of oxidation reactions of lipids may occur ... 

Figure 3.45 Fission of fatty acid hydrocarbon chain during hydroperoxide decomposition.

Essential oils consist of volatile, lipophilic substances that are mainly hydrocarbons or monofunctional compounds derived from the metabolism of mono- and sesquiterpenes, phenylpropanoids, amino acids (lower mass aliphatic compounds), and fatty acids (long-chain aliphatic compounds). Unlike fatty oils, essential oils do not leave a grease stain when dabbed on filter paper. 

Cholesterol probably orients such that its hydroxyl group is in the polar (aqueous) portion of the lipid bilayer, while its hydrocarbon portion is in the nonpolar (fatty acid side-chain) region. 

Aliphatic hydrocarbons such as n-alkanes and n-alkenes have been successfully used to distinguish between algal, bacterial, and terrestrial sources of carbon in estuarine/coastal systems (Yunker et al., 1991, 1993, 1995 Canuel et al., 1997). Saturated aliphatic hydrocarbons are considered to be alkanes (or paraffins) and nonsaturated hydrocarbons which exhibit one or more double bonds are called alkenes (or olefins)—as indicated in the simple structures of hexadecane and 1,3-butadiene, respectively (figure 9.7). It should also be noted that, n-alkanes tend to be odd-numbered as they result from enzymatic decarboxylation of fatty acids. Long-chain n-alkanes (LCH) (e.g., C27, C29, and C31) are generally considered to be terrestrially derived, originating from epicuticular waxes... 

Hydrophobic packing materials such as divinylbenzene [82] or chemically modified silica (C8, C 8) [102] are recommended for removing aromatics, long-chain fatty acids, hydrocarbons, and surfactants from the sample. In contrast to ODS materials, divinylbenzene has the advantage of being stable over a broad pH range (pH 0 to 14). Also, divinylbenzene shows a higher selectivity for aromatic and unsaturated compounds. 

The most common fatty acids are chains of 12 to 26 carbon atoms with a carboxylic acid group at one end. They usually have an even number of carbon atoms because they are made from smaller molecules with two carbons. Saturated fatty acids, like saturated hydrocarbons, have only single bonds connecting the carbon atoms. Monounsaturated fatty acids have one double bond between two of the carbon atoms, as you can see in Figure 19.11. Fatty acids that are polyunsaturated have two or more double bonds. In general, animal lipids are more saturated than are plant lipids. 

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