Related Posts:

The molecular structure of a phospholipid is shown. It consists of two fatty acids attached to the first and second carbons in glycerol, and a phosphate group attached to the third position. The phosphate group may be further modified by addition of another molecule to one of its oxygens. Two molecules that may modify the phosphate group, choline and serine, are shown. Choline consists of a two-carbon chain with a hydroxy group attached to one end and a nitrogen attached to the other. The nitrogen, in turn, has three methyl groups attached to it and has a charge of plus one. Serine consists of a two-carbon chain with a hydroxyl group attached to one end. An amino group and a carboxyl group are attached to the other end.
A phospholipid is a molecule with two fatty acids and a modified phosphate group attached to a glycerol backbone. Adding a charged or polar chemical group may modify the phosphate.

Source: OpenStax Biology 2e

Phospholipids (OpenStax Biology 2e)

Phospholipids are major plasma membrane constituents that comprise cells’ outermost layer. Like fats, they are comprised of fatty acid chains attached to a glycerol or sphingosine backbone. However, instead of three fatty acids attached as in triglycerides, there are two fatty acids forming diacylglycerol, and a modified phosphate group occupies the glycerol backbone’s third carbon. A phosphate group alone attached to a diacylglycerol does not qualify as a phospholipid. It is phosphatidate (diacylglycerol 3-phosphate), the precursor of phospholipids. An alcohol modifies the phosphate group. Phosphatidylcholine and phosphatidylserine are two important phospholipids that are in plasma membranes.

– Phospholipids are the major components of what cell structure?

The first phospholipid identified in 1847 as such in biological tissues was lecithin, or phosphatidylcholine, in the egg yolk of chickens by the French chemist and pharmacist Theodore Nicolas Gobley.

A phospholipid is an amphipathic molecule, meaning it has a hydrophobic and a hydrophilic part. The fatty acid chains are hydrophobic and cannot interact with water; whereas, the phosphate-containing group is hydrophilic and interacts with water.

An illustration of a phospholipids bilayer is shown. The phospholipids bilayer consists of two layers of phospholipids. The hydrophobic tails of the phospholipids face one another while the hydrophilic head groups face outward.
The phospholipid bilayer is the major component of all cellular membranes. The hydrophilic head groups of the phospholipids face the aqueous solution. The hydrophobic tails are sequestered in the middle of the bilayer.

Source: OpenStax Biology 2e

The head is the hydrophilic part, and the tail contains the hydrophobic fatty acids. In a membrane, a bilayer of phospholipids forms the structure’s matrix, phospholipids’ fatty acid tails face inside, away from water; whereas, the phosphate group faces the outside, aqueous side.

Phospholipids are responsible for the plasma membrane’s dynamic nature. If a drop of phospholipids is placed in water, it spontaneously forms a structure that scientists call a micelle, where the hydrophilic phosphate heads face the outside and the fatty acids face the structure’s interior.

– Phospholipid synthesis occurs in the cytosolic side of what cell structure?

Phospholipids have been widely used to prepare liposomal, ethosomal and other nanoformulations of topical, oral and parenteral drugs for differing reasons like improved bio-availability, reduced toxicity and increased permeability across membranes.


Clark, M., Douglas, M., Choi, J. Biology 2e. Houston, Texas: OpenStax. Access for free at:

Related Research

Research Article: Phospholipid transfer by ERMES components

Date Published: April 28, 2018 Publisher: Impact Journals Author(s): Toshiya Endo, Yasushi Tamura, Shin Kawano. Abstract: Partial Text   Source:  

Research Article: Flip-Flop of Phospholipids in Proteoliposomes Reconstituted from Detergent Extract of Chloroplast Membranes: Kinetics and Phospholipid Specificity

Date Published: December 12, 2011 Publisher: Public Library of Science Author(s): Archita Rajasekharan, Sathyanarayana N. Gummadi, Wanjin Hong. Abstract: Eukaryotic cells are compartmentalized into distinct sub-cellular organelles by lipid bilayers, which are known to be involved in numerous cellular processes. The wide repertoire of lipids, synthesized in the biogenic membranes like the endoplasmic reticulum and … Continue reading

Research Article: Phospholipid Complex Technique for Superior Bioavailability of Phytoconstituents

Date Published: April 13, 2017 Publisher: Tabriz University of Medical Sciences Author(s): Kattamanchi Gnananath, Kalakonda Sri Nataraj, Battu Ganga Rao. Abstract: Phytoconstituents have been utilized as medicines for thousands of years, yet their application is limited owing to major hurdles like deficit lipid solubility, large molecular size and degradation in the gastric environment of … Continue reading

Research Article: Morphological and Physical Analysis of Natural Phospholipids-Based Biomembranes

Date Published: September 19, 2014 Publisher: Public Library of Science Author(s): Adrien Jacquot, Grégory Francius, Angelina Razafitianamaharavo, Fariba Dehghani, Ali Tamayol, Michel Linder, Elmira Arab-Tehrany, Etienne Dague. Abstract: Liposomes are currently an important part of biological, pharmaceutical, medical and nutritional research, as they are considered to be among the most effective carriers for the … Continue reading

Research Article: Measurement of Phospholipids May Improve Diagnostic Accuracy in Ovarian Cancer

Date Published: October 17, 2012 Publisher: Public Library of Science Author(s): Lian Shan, Y. Ann Chen, Lorelei Davis, Gang Han, Weiwei Zhu, Ashley D. Molina, Hector Arango, James P. LaPolla, Mitchell S. Hoffman, Thomas Sellers, Tyler Kirby, Santo V. Nicosia, Rebecca Sutphen, Anthony WI. Lo. Abstract: More than two-thirds of women who undergo surgery for … Continue reading

Research Article: DNA Nanotechnology Enters Cell Membranes

Date Published: March 20, 2019 Publisher: John Wiley and Sons Inc. Author(s): Shuaidong Huo, Hongyan Li, Arnold J. Boersma, Andreas Herrmann. Abstract: DNA is more than a carrier of genetic information: It is a highly versatile structural motif for the assembly of nanostructures, giving rise to a wide range of functionalities. In this regard, … Continue reading