Glycerophospholipids are amphiphilic lipids consisting of a glycerol backbone esterified at the sn-1 and sn-2 positions with fatty acyl chains and at the sn-3 position with a phosphate group linked to a polar head such as choline, ethanolamine, serine or inositol. They constitute the primary structural components of cellular membranes, forming bilayers that regulate fluidity, permeability and protein function. In food systems they act as natural emulsifiers, stabilizers and antioxidants, commonly derived from soy, egg yolk and sunflower. They participate in signal transduction pathways via hydrolysis to second messengers like diacylglycerol and inositol phosphates. Their physical properties vary with chain length and saturation, influencing phase transition temperatures and membrane packing.