Lipid Catabolism and Anabolism Essay

Lipid catabolism, or lipolysis, is the process of breaking down the molecules of lipids into simpler ones, with release of energy. Under the influence of lipases (a type of enzymes), lipids break down into glycerol and free fatty acids (“Lipid and Protein Catabolism” n. pag.). These free fatty acids then become available for cellular uptake; they are bound by albumin and then transported to tissues and cells requiring energy (King n. pag.). Then, these fatty acids are β-oxidated and thus transformed into acetyl-CoA; the latter may undergo the Krebs cycle and be broken down further (“Lipid and Protein Catabolism” n. pag.). Meanwhile, glycerol can also be decomposed in the process of glycolysis (“Glycolysis” n. pag.).Lipid Catabolism and Anabolism Essay

Lipid anabolism, on the other hand, is the process of synthesizing the molecules of lipids from simpler ones so as to store energy. Lipids are synthesized from carbohydrates when there is an oversupply of them. In the process, fatty acids are created in the presence of synthases (catalyzing enzymes) from acetyl-CoA (“Lipid Biosynthesis” n. pag.). After that, these fatty acids are joined with a variation of glycerol, which results in a molecule of phosphatidic acid, to which a “hydrophilic portion of the lipid is added,” creating a molecule of a lipid (Paustian n. pag.). It is worth noting that certain lipids cannot be synthesized in some organisms, and must be obtained via food.Lipid Catabolism and Anabolism Essay

Speaking about the structure and function of lipids, it is worth pointing out that lipids are often hydrophobic, which allows them to be parts of cell membranes and form water-repellent integuments, and regulate the permeability of cells. At the same time, when decomposed, lipids produce a vast amount of energy, which is why they are used by most organisms to store energy.

To give an example, triacylglycerols (dietary fats) in the process of catabolism are broken down into two molecules of fatty acids and a molecule of monoacylglycerol in the presence of lipase. After that, the resulting molecules are transported into enterocytes (intestinal absorptive cells). There, they might be reattached again to form triacylglycerol, then be wrapped in proteins and transported around the body (“Lipid Metabolism” 1-2).