Phospholipid

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A composite diagram shows the structural formulas, space-filling models, and simplified depictions of lipid molecules including stearic acid and phosphatidylcholine, and how these assemble into a micelle and lipid bilayer, with labels identifying hydrophilic heads and hydrophobic tails.

Detailed diagram of a plasma membrane's lipid bilayer showing two layers of phospholipid molecules with hydrophilic heads facing outward and hydrophobic tails inward, embedded cholesterol, integral (intrinsic) proteins spanning the membrane, peripheral (extrinsic) proteins attached to the surface, and sugar side chains extending from the outer face.

structure of an inverted or reverse micelle

Simple diagram of a lipid bilayer showing two layers of phospholipid molecules with round hydrophilic heads facing outward and hydrophobic tails facing inward, illustrating a cellular membrane structure.

Cross-sectional diagram of a liposome, showing concentric bilayers formed by phospholipid molecules with pink heads and blue fatty acid tails, illustrating its structure in biochemistry.

A detailed cross-section illustration of a low-density lipoprotein (LDL) complex shows a spherical structure with a phospholipid monolayer, embedded apoprotein (apoB-100), and internal components such as cholesteryl esters, free cholesterol, and triacylglycerol molecules.

Diagram of a cell membrane showing three types of membrane transport: simple diffusion of small molecules, facilitated diffusion through transporter proteins, and primary active transport using ATP to move molecules across the membrane. Labels identify the hydrophilic heads and hydrophobic tails of phospholipids, as well as extracellular and intracellular surfaces.

Phospholipid: References & Edit History

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Article History

Type	Description	Contributor	Date
	Article title updated for style.	The Editors of Encyclopaedia Britannica	Nov 11, 2026
	Modified link of Web site: Chemistry LibreTexts - Phospholipids.	Grace Young	Nov 01, 2026
	Add new Web site: Mustansiriyah University - Phospholipids metabolism (PDF).	Yamini Chauhan	Jan 21, 2025
	Add new Web site: Nature - Nature Communications - A minimal biochemical route towards de novo formation of synthetic phospholipid membranes.	Gloria Lotha	Oct 11, 2024
	Add new Web site: Nature - Nature Communications - A minimal biochemical route towards de novo formation of synthetic phospholipid membranes.	Gloria Lotha	Oct 11, 2024
	Add new Web site: Academia - Phospholipid signalling in plant defence.	Yamini Chauhan	Aug 26, 2024
	Add new Web site: CORE - Phospholipids of Animal and Marine Origin: Structure, Function, and Anti-Inflammatory Properties.	Gloria Lotha	Sep 29, 2023
	Add new Web site: Journal of Biological Chemistry - Understanding phospholipid function: Why are there so many lipids?	Gloria Lotha	Jul 31, 2023
	Add new Web site: Frontiers - The Crucial Roles of Phospholipids in Aging and Lifespan Regulation.	Gloria Lotha	Apr 15, 2023
	Add new Web site: Chemistry LibreTexts - Phospholipids.	Emily Rodriguez	Feb 12, 2023
	Add new Web site: Khan Academy - Phospholipid structure.	Emily Rodriguez	Jan 25, 2022
	Add new Web site: National Center for Biotechnology Information - PubMed Central - Health effects of dietary phospholipids.	Emily Rodriguez	Jan 25, 2022
	New illustration added.	Kara Rogers	Jan 15, 2009
	Added new Web site: RCN Corporation - Phospholipids.	Deepti Mahajan	Apr 09, 2008
	Article added to new online database.	The Editors of Encyclopaedia Britannica	Jul 20, 1998