Title: molecular shape of lipids
Long Title: IUPAC Gold Book - molecular shape of lipids
DOI: 10.1351/goldbook.09851
Status: current

Definition
Specific structure of lipid molecules (glycerophospholipids) in aqueous environments and membranes as a function of the ratio between the cross-sections of their polar heads and hydrophobic tails.

Notes
1) Lipids’ ability to self-assemble in dynamic macrostructures in an aqueous medium is driven by the amphiphilic nature of lipid molecules, which tend to aggregate so that the hydrophobic (tails) and the hydrophilic (heads) parts of the lipid are well separated and the area of the dividing surface is held by the hydrophobic effect.
2) The shape of a membrane lipid depends on the relative size of its polar headgroup and apolar tails. In cases in which the headgroup and lipid backbone have similar cross-sectional areas, the molecule has a cylindrical shape (phosphatidylcholine and phosphatidylserine). Lipids with a small headgroup, such as phosphatidylethanolamine, are conical shaped. By contrast, when the hydrophobic part occupies a relatively smaller surface area, the molecule has the shape of an inverted cone (lysophosphatidylcholine and, to some extent, sphingomyelin).

Related Term
- glycerophospholipids: https://goldbook.iupac.org//terms/view/09839

Source
- PAC, 2018, 90, 1121. 'Terminology of bioanalytical methods (IUPAC Recommendations 2018)' on page 1180 (https://doi.org/10.1515/pac-2016-1120)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09851/html
- json: https://goldbook.iupac.org/terms/view/09851/json
- xml: https://goldbook.iupac.org/terms/view/09851/xml

Citation: Citation: 'molecular shape of lipids' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09851
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Accessed: 2026-08-02T10:14:35+00:00