Fatty acids are organic compounds that fall under the category of lipids, which are essential biomacromolecules in the living system. The fatty acid types are saturated, unsaturated, and polyunsaturated fatty acids. Fatty acids play an important role in various physiological processes of the living organism, such as metabolism, formation, and maintenance of cell structure. In this article, we will study the structure, properties, function, and type of fatty acids in detail.

Fatty Acids – Definition and Meaning

Fatty Acids Definition: Fatty acid is an organic biomacromolecule comprising a hydrocarbon chain and a carboxyl group that is a fundamental building block of the living system.

Fatty acids are essential components of various physiological mechanisms of the body. They have varying length that ranges from 4 to 24 carbon atoms, and can have single or double bonds. The hydrocarbon chain of fatty acids ends with a carboxylic acid group. They are the fundamental building blocks of lipid molecules. Fatty acids are responsible for the maintenance and regulation of various cellular functions, synthesis of signalling molecules, hormone regulation, energy storage, inflammatory response, etc.

Also Read: What are Lipids? – Function, Structure, Definition of Lipids

Fatty Acid

Fatty Acids Formula

Fatty acids are carboxylic acids with a long hydrocarbon chain. Their general formula is CH3(CH2)nCOOH, where n represents the number of carbon atoms in the chain (typically between 12 and 20). This formula indicates a terminal methyl group (CH3), a chain of methylene groups (CH2), and a carboxylic acid group (COOH). The variation in “n” determines the specific type of fatty acid.

Essential Fatty Acids

Essential fatty acids are important types of polyunsaturated fatty aicds that our bodies need to function properly. We can not make them ourselves, so we have to get them from the food we eat. The two categories of essential fatty acid foods include omega-3 and omega-6, which are vital for proper body function.

The omega numbers indicate the position of the first carbon double bond in the fatty acid chain. These fats produce eicosanoids, regulating immune and nervous systems. Omega-3 promotes heart health, while omega-6 increases inflammation and blood pressure. Balancing omega-3 and omega-6 intake in the diet is essential due to their differing effects.

Essential Fatty Acid Foods

Some foods which are high in essential fatty acids are:

Fatty Acids Omega-3

• Fatty fish such as salmon, mackerel, and sardines
• Flaxseeds and chia seeds
• Walnuts
• Soybeans

Fatty Acids Omega-6

• Vegetable oils like
  • corn oil
  • soybean oil
  • sunflower oil
• Nuts such as
  • almonds,
  • sunflower seeds
  • pine nuts
  • walnuts

Properties of Fatty Acids

Some of the common properties of fatty acids are:

• They have varied chain lengths.
• Short-chain fatty acids have around 6 or less carbon atoms, medium-chained fatty acids have between 6 to 12 carbon atoms, and long-chain fatty acids have around 12 or more carbon atoms.
• The degree of saturation depends on the presence and absence of double bonds between the carbon atoms.
• Saturated fatty acids lack double bonds and are solid at room temperature.
• Unsaturated fatty acids have one or more double bonds and are liquid at room temperature.
• Saturated fatty acids require more temperature to melt as compared to unsaturated fatty acids.
• If the fatty acids undergo hydrogenation they may show trans-configuration and are called trans fat.
• In the natural state, the unsaturated fatty acids mostly show cis-configuration.
• Saturated fatty acids are less reactive whereas unsaturated fatty acids are more reactive and can undergo oxidation.

Also Read: Difference Between Fats and Lipids

Structure of Fatty Acids

Following are some of the aspects of the structure of fatty acids:

• They are made of hydrocarbon chains and the number of carbon atoms can vary from 4 to 24 atoms making the molecule short or long-chained.
• At one end of the chain, there is one carboxyl group (-COOH) attached.
• When the carbon and hydrogen of the chain are bound to each other by a single bond it forms a straight structure of the saturated fatty acids.
• When the carbon and hydrogen of the chain are bound to each other by double bonds it forms bends in the structure of the unsaturated fatty acids.
• Other than the carboxyl group some fatty acids may have other functional groups like hydroxyl group.

Types of Fatty Acids

Following are some of the different types of fatty acids based on the presence, or absence of double bonds and chain length.

Saturated and Unsaturated Fatty Acids

The key differences between saturated and unsaturated fatty acids are: