In the study of lipids, we transition from fatty acid-based lipids to isoprenoids, which represent a distinct branch of lipids. Isoprenoids are constructed from two or more units of isoprene, a five-carbon molecule with the IUPAC name 2-methyl-1,3-butadiene. This molecule features a main chain of four carbon atoms, indicated by the "buta" prefix, and contains two double bonds at the first and third carbon positions, as denoted by "1,3-diene." The "2-methyl" refers to a methyl group branching off the second carbon.
By linking multiple isoprene units, we can form various isoprenoids, which are categorized into three major classes: terpenes and terpenoids, steroids, and lipid vitamins. Terpenes and terpenoids are often recognized for their roles in plant biology and aroma, while steroids are crucial for various biological functions, including hormone regulation. Lipid vitamins, such as vitamins A, D, E, and K, are essential for numerous physiological processes.
Understanding these classes of isoprenoids is vital as we delve deeper into their specific functions and structures in subsequent lessons. This foundational knowledge sets the stage for exploring the diverse roles that isoprenoids play in biological systems.