Oleic acid is a common unsaturated fatty acid. Stearic acid is an example of a saturated fatty acid (Figure 3)įigure 4. Saturated fatty acids are saturated with hydrogen in other words, the number of hydrogen atoms attached to the carbon skeleton is maximized.
In a fatty acid chain, if there are only single bonds between neighboring carbons in the hydrocarbon chain, the fatty acid is said to be saturated. Arachidic acid is derived from Arachis hypogea, the scientific name for groundnuts or peanuts.įatty acids may be saturated or unsaturated. For example, palmitic acid, a saturated fatty acid, is derived from the palm tree. Some fatty acids have common names that specify their origin. Fats are also called triacylglycerols or triglycerides because of their chemical structure. The three fatty acids in the triacylglycerol may be similar or dissimilar. Three molecules of water are released in the process.ĭuring this ester bond formation, three water molecules are released. Triacylglycerol is formed by the joining of three fatty acids to a glycerol backbone in a dehydration reaction. In a fat molecule, the fatty acids are attached to each of the three carbons of the glycerol molecule with an ester bond through an oxygen atom (Figure 2).įigure 2. Fatty acids have a long chain of hydrocarbons to which a carboxyl group is attached, hence the name “fatty acid.” The number of carbons in the fatty acid may range from 4 to 36 most common are those containing 12–18 carbons. Glycerol is an organic compound (alcohol) with three carbons, five hydrogens, and three hydroxyl (OH) groups. Fats and OilsĪ fat molecule consists of two main components-glycerol and fatty acids. Lipids include fats, oils, waxes, phospholipids, and steroids. Lipids are also the building blocks of many hormones and are an important constituent of all cellular membranes. For example, they help keep aquatic birds and mammals dry when forming a protective layer over fur or feathers because of their water-repellant hydrophobic nature. Lipids also provide insulation from the environment for plants and animals (Figure 1). Cells store energy for long-term use in the form of fats. Lipids perform many different functions in a cell. Non-polar molecules are hydrophobic (“water fearing”), or insoluble in water. This is because they are hydrocarbons that include mostly nonpolar carbon–carbon or carbon–hydrogen bonds. Lipids include a diverse group of compounds that are largely nonpolar in nature. Hydrophobic lipids in the fur of aquatic mammals, such as this river otter, protect them from the elements.
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