fatty acid

(noun)

Any of a class of aliphatic carboxylic acids, of general formula CnH2n+1COOH, that occur combined with glycerol as animal or vegetable oils and fats. Only those with an even number of carbon atoms are normally found in natural fats.

Related Terms

Examples of fatty acid in the following topics:

  • Lipid Metabolism

    • Fatty acids are the building blocks of lipids.
    • The fatty acid structure (see below) is one of the most fundamental categories of biological lipids.
    • Activation: Before fatty acids can be metabolized, they must be "activated. " This activation step involves the addition of a coenzyme A (CoA) molecule to the end of a long-chain fatty acid, after which the activated fatty acid (fatty acyl-CoA) enters the β-oxidation pathway.
    • A fatty acid is a carboxylic acid with a long aliphatic tail that may be either saturated or unsaturated.
    • The molecule shown here is the eight-carbon saturated fatty acid known as octanoic acid (or caprylic acid).

  • Organic Acid Metabolism

    • Many bacteria are capable of utilizing fatty acids of various tail lengths as sole energy and carbon sources.
    • This process requires the β-oxidation pathway, a cyclic process that catalyzes the sequential shortening of fatty acid acyl chains to the final product, acetyl-CoA.
    • Fatty acid chains are converted to enoyl-CoA (catalyzed by acyl-CoA dehydrogenase).
    • The fatty acid chain that is left over after the thiolation step can then reenter the β-oxidation pathway, which can cycle until the fatty acid has been completely reduced to acetyl-CoA.
    • Free fatty acids are broken down to acetyl-CoA by dedicated enzymes in the β-oxidation pathway.

  • Lipid Biosynthesis

    • This involves the synthesis of fatty acids from acetyl-CoA and the esterification of fatty acids in the production of triglycerides, a process called lipogenesis.
    • Fatty acids are made by fatty acid synthases that polymerize and then reduce acetyl-CoA units.
    • The synthesis of unsaturated fatty acids involves a desaturation reaction, whereby a double bond is introduced into the fatty acyl chain.
    • The doubly unsaturated fatty acid linoleic acid as well as the triply unsaturated α-linolenic acid cannot be synthesized in mammalian tissues, and are therefore essential fatty acids and must be obtained from the diet.
    • Outline the characteristics and processes of lipid biosynthesis, including:; lipogenesis and fatty acid biosynthesis

  • Clostridial and Propionic Acid Fermentation

    • Acetogenesis is a biological reaction wherein volatile fatty acids are converted into acetic acid, carbon dioxide, and hydrogen.
    • Acidogenesis is a biological reaction wherein simple monomers are converted into volatile fatty acids.
    • Acetogenes is a biological reaction wherein volatile fatty acids are converted into acetic acid, carbon dioxide, and hydrogen .
    • The hydrolyzed compounds are fermented into volatile fatty acids (acetate, propionate, butyrate, and lactate), neutral compounds (ethanol, methanol), ammonia, hydrogen and carbon dioxide.
    • Acetic acid is equally a co-metabolite of the organic substrates' fermentation (sugars, glycerol, lactic acid, etc.) by diverse groups of microorganisms, which produce different acids:

  • The Pentose Phosphate Shunt

    • These compounds are used in a variety of different biological processes including production of nucleotides and nucleic acids (ribose-5-phosphate), as well as synthesis of aromatic amino acids (erythrose-4-phosphate).
    • NADPH-utilizing pathways, such as fatty acid synthesis, generate NADP+, which stimulates glucose-6-phosphate dehydrogenase to produce more NADPH.
    • It is used in reductive biosynthesis reactions within cells (e.g. fatty acid synthesis).
    • It also produces nucleic acids and erythrose-4-phosphate, used in the synthesis of aromatic amino acids.

  • Pyruvic Acid and Metabolism

    • Pyruvic acid (CH3COCOOH) is an organic acid, a ketone, and the simplest of the alpha-keto acids.
    • Pyruvic acid (CH3COCOOH; is an organic acid, a ketone, and the simplest of the alpha-keto acids.
    • Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through acetyl-CoA.
    • Pyruvate can be converted into carbohydrates via gluconeogenesis, to fatty acids or energy through acetyl-CoA, to the amino acid alanine, and to ethanol.
    • Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through acetyl-CoA.

  • Types of Catabolism

    • Fats are catabolised by hydrolysis to free fatty acids and glycerol.
    • The glycerol initiates glycolysis and the fatty acids are broken down by beta oxidation to release acetyl-CoA, which then is fed into the citric acid cycle.
    • Fatty acids release more energy upon oxidation than carbohydrates because carbohydrates contain more oxygen in their structures.
    • Several of these keto acids are intermediates in the citric acid cycle, for example the deamination of glutamate forms α-ketoglutarate.
    • The glucogenic amino acids can also be converted into glucose, through gluconeogenesis.

  • Fermentation Without Substrate-Level Phosphorylation

    • Homolactic fermentation is the production of lactic acid from pyruvate; alcoholic fermentation is the conversion of pyruvate into ethanol and carbon dioxide; and heterolactic fermentation is the production of lactic acid as well as other acids and alcohols.
    • However, more exotic compounds can be produced by fermentation, such as butyric acid and acetone.
    • Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through acetyl-CoA.
    • It can also be used to construct the amino acid alanine and be converted into ethanol.
    • Pyruvic acid supplies energy to living cells through the citric acid cycle (also known as the Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactic acid when oxygen is lacking (fermentation).

  • Fermented Foods

    • Fermentation is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using microorganisms.
    • Fermentation in food processing typically is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination thereof, under anaerobic conditions.
    • Fermentation is also employed in the leavening of bread (CO2 produced by yeast activity); in preservation techniques to produce lactic acid in sour foods such as sauerkraut, dry sausages, kimchi, and yogurt; and in the pickling of foods with vinegar (acetic acid).
    • Preservation of substantial amounts of food through lactic acid, alcohol, acetic acid, and alkaline fermentations.
    • Biological enrichment of food substrates with protein, essential amino acids, essential fatty acids, and vitamins.

  • Nature of the Virion

    • A virion is an entire virus particle consisting of an outer protein shell called a capsid and an inner core of nucleic acid (either ribonucleic or deoxyribonucleic acid—RNA or DNA).
    • In some virions the capsid is further enveloped by a fatty membrane, in which case the virion can be inactivated by exposure to fat solvents such as ether and chloroform.
    • The nucleic acid is densely coiled within.
    • Virions of most plant viruses are rod-shaped; the capsid is a naked cylinder (lacking a fatty membrane) within which lies a straight or helical rod of nucleic acid.
    • Proteins associated with nucleic acid are known as nucleoproteins, and the association of viral capsid proteins with viral nucleic acid is called a nucleocapsid.