Lipidien

Lipidien are a broad class of biomolecules that are hydrophobic or amphipathic and play diverse roles in biology. They are largely insoluble in water and are soluble in organic solvents, reflecting their hydrocarbon-rich structures. Lipidien include triglycerides, phospholipids, glycolipids, sterols, waxes, and lipid-soluble vitamins, and they do not form polymers like proteins and nucleic acids.

The major categories of lipidien are storage lipids (neutral lipids such as triglycerides and esters that store energy), membrane lipids (phospholipids and glycolipids that form cellular membranes and organelle membranes), sterols (such as cholesterol and bile acids that regulate fluidity and serve as hormone precursors), and lipid-soluble vitamins (A, D, E, K). Phospholipids typically have two fatty acid tails and a glycerol-phosphate head group, yielding amphipathic molecules that arrange into bilayers and micelles. Cholesterol modulates membrane fluidity and serves as a precursor for steroid hormones.

Biochemical roles extend to energy storage, membrane architecture, and signaling. Lipidien can be metabolized to generate adenosine triphosphate (ATP) through beta-oxidation, particularly in mitochondria. They also participate in intracellular signaling as precursors to molecules such as eicosanoids and steroid hormones. Dietary lipidien influence health, providing essential fatty acids and fat-soluble vitamins, while imbalances can be associated with metabolic and cardiovascular diseases.