Lipiid

Lipiid is a term occasionally used in scientific literature as an alternate spelling or transliteration of lipid, a broad class of organic molecules essential to living organisms. Lipids are characterized by hydrophobic or amphipathic properties and limited water solubility. The spelling lipiid is not universally preferred in English, but appears in some languages and older sources.

Classifications commonly include triglycerides, phospholipids, sterols, and glycolipids. Triglycerides store energy in adipose tissue; phospholipids and glycolipids form cell membranes and mediate interactions with proteins; sterols such as cholesterol participate in membrane fluidity and steroid hormone synthesis. Lipids differ in structure but often share amphipathic character and tendencies to assemble into membranes, droplets, or signaling complexes.

Physicochemical properties: many lipids have long hydrocarbon chains or ring systems with polar head groups, enabling interactions with water, proteins, and other lipids. They can be saturated or unsaturated, influencing membrane properties and melting points.

Biological roles and metabolism: lipids serve as energy reserves, membrane components, and precursors to signaling molecules. They are synthesized by lipogenic pathways in liver and adipose tissue; mobilized by lipolysis and oxidized via beta-oxidation to generate energy. Dietary lipids are absorbed as fatty acids and monoglycerides and transported in lipoproteins.

Terminology note: while lipiid is uncommon in modern English, the term lipid remains the standard. For broader context, see lipid, fatty acid, phospholipid.