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Phospholipids have amphipathic character.
Amphiphile (from the Greek αμφις, amphis: both and φιλíα, philia: love, friendship) is a term describing a chemical compound possessing both hydrophilic and hydrophobic properties. Such a compound is called amphiphilic or amphipathic. This forms the basis for a number of areas of research in chemistry and biochemistry, notably that of lipid polymorphism. Organic compounds containing hydrophilic groups at both ends of a prolate molecule are called bolaamphiphile

Structure and Properties

The hydrophobic group is typically a large hydrocarbon moiety, such as a long chain of the form CH3(CH2)n, with n > 4. The hydrophilic group falls into one of the following categories:
  1. Charged groups
  2. * Anionic. Examples, with the hydrophobic part of the molecule represented by an R, are:
  3. ** carboxylates: RCO2-;
  4. ** sulfates: RSO4-;
  5. ** sulfonates: RSO3-.
  6. ** phosphates: The charged functionality in phospholipids.
  7. * Cationic. Examples:
  8. ** amines: RNH3+.
  9. Polar, uncharged groups. Examples are alcohols with large R groups, such as diacyl glycerol (DAG), and oligoethyleneglycols with long alkyl chains.


Often, amphiphilic species have several hydrophobic parts, several hydrophilic parts, or several of both. Proteins and some block copolymers are such examples.

Molecules of amphiphilic compounds have hydrophobic (usually of hydrocarbon nature) and hydrophilic (represented by either ionic or uncharged polar functional groups) structural regions.

As a result of having both hydrophobic and hydrophilic structural regions, some amphiphilic compounds may dissolve in water and to some extent in non-polar organic solvents.

When placed in an immiscible biphasic system consisting of aqueous and hydrophobic solvent the amphiphilic compound will partition the two phases. The balance between hydrophobic and hydrophilic natures defines the extent of partitioning.

Biological role

Phospholipids, a class of amphiphilic molecules, are the main components of biological membranes. The amphiphilic nature of these molecules defines the way in which they form membranes. They arrange themselves into bilayers, by positioning their polar groups towards the surrounding aqueous medium, and their hydrophobic chains towards the inside of the bilayer, defining a non-polar region between two polar ones.

Although phospholipids are principal constituents of biological membranes, there are other amphiphilic molecules, such as cholesterol and glycolipids, which are also included in these structures and give them different physical and biological properties.

Many other amphiphilic compounds strongly interact with biological membranes by insertion of hydrophobic part into the lipid membrane, while exposing the hydrophilic part to the aqueous medium, altering their physical behaviour and sometimes disrupting them.

Examples of amphiphiles

There are several examples of molecules that present amphiphilic properties:

Surfactants are an example group of amphiphilic compounds. Their polar region can be either ionic, or non-ionic. Some typical members of this group are: sodium dodecyl sulphate (anionic), Benzalkonium chloride (cationic), Cocamidopropyl betaine (zwitterionic) and octanol (long chain alcohol, non-ionic).

Many biological compounds are amphiphilic: phospholipids, cholesterol, glycolipids, fatty acids, bile acids, saponins, etc.

See also

 •  • [ e]
Articles related to solutions
SolutionIdeal solution • Aqueous solution • Solid solution • Flory-Huggins • Mixture • Suspension (chemistry) • Colloid • Phase diagram • Eutectic point • Alloy
ConcentrationSaturation (chemistry) • Supersaturation • Molar solution • Percentage solution
SolubilitySolubility equilibrium • Total dissolved solids • Dissolve • Solvation • Enthalpy change of solution • Lattice energy • Henry's law • Solubility table (data) • Solubility chart
Solvent() • Acid dissociation constant • Protic solvent • Inorganic nonaqueous solvent • Solvation • Solvation shell • List of boiling and freezing information of solvents
Partition coefficient • Polarity • Hydrophobe • Hydrophile • Lipophilic • Amphiphile
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For other uses of "philia", see Philia (disambiguation).
"Philia" (Greek: φιλíα) in Aristotle's Nicomachean Ethics is usually translated "friendship",[1]
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Hydrophile, from the Greek (hydros) "water" and φιλια (philia) "friendship," refers to a physical property of a molecule that can transiently bond with water (H2O) through hydrogen bonding.
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hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of a molecule (known as a hydrophobe) that is repelled from a mass of water [1].
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Polymorphism in biophysics is the aspect of the behaviour of lipids that influences their long-range order, i.e. how they aggregate. This can be in the form of spheres of lipid molecules (micelles), pairs of layers that face one another (lamellar phase, observed in biological
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A prolate spheroid is a spheroid in which the polar diameter is longer than the equatorial diameter.

Prolate spheroids in sport

The prolate spheroid is the shape of the ball in several sports, such as Rugby Football and Australian Rules Football.
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Bolaamphiphiles (also known as bolaform surfactants, bolaphiles, or alpha-omega-type surfactants) are amphiphilic molecules that have hydrophilic groups at both ends of a sufficiently long hydrophobic hydrocarbon chain.
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hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of a molecule (known as a hydrophobe) that is repelled from a mass of water [1].
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hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. With relation to chemical terminology, aromatic hydrocarbons or arenes, alkanes, alkenes and alkyne-based compounds composed entirely of carbon or hydrogen are referred to as "Pure" hydrocarbons, whereas
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In organic chemistry, functional groups (or moieties) are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules.
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Hydrophile, from the Greek (hydros) "water" and φιλια (philia) "friendship," refers to a physical property of a molecule that can transiently bond with water (H2O) through hydrogen bonding.
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ion is an atom or molecule which has lost or gained one or more electrons, making it positively or negatively charged. A negatively charged ion, which has more electrons in its electron shells than it has protons in its nuclei, is known as an anion
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Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)OH, usually written -COOH or -CO2H. [1] Carboxylic acids are Bronsted acids — they are proton donors.
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In inorganic chemistry, a sulfate (IUPAC-recommended spelling; also sulphate in British English) is a salt of sulfuric acid.

Chemical properties

The sulfate ion is a polyatomic anion with the empirical formula SO42−
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A sulfonate ion is an ion that contains the -S(=O)2-O− functional group. The general formula is RSO2O−, where R is some organic group.
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A phosphate, in inorganic chemistry, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Phosphates are important in biochemistry and biogeochemistry.
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U indicates the uncharged hydrophobic portion of the molecule, highlighted in blue.]]

Phospholipids are a class of lipids, and a major component of all biological membranes, along with glycolipids, cholesterol and proteins.
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alcohol is any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group. The general formula for a simple acyclic alcohol is CnH2n+1OH.
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Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze.
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Proteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues.
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A heteropolymer or copolymer is a polymer derived from two (or more) monomeric species, as opposed to a homopolymer where only one monomer is used.[1] Copolymerization refers to methods used to chemically synthesize a copolymer.
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hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of a molecule (known as a hydrophobe) that is repelled from a mass of water [1].
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A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. The most common solvent in everyday life is water. Most other commonly-used solvents are organic (carbon-containing) chemicals. These are called organic solvents.
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U indicates the uncharged hydrophobic portion of the molecule, highlighted in blue.]]

Phospholipids are a class of lipids, and a major component of all biological membranes, along with glycolipids, cholesterol and proteins.
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lipid bilayer or bilayer lipid membrane (BLM) is a membrane or zone of a membrane composed of lipid molecules (usually phospholipids). The lipid bilayer is a critical component of all biological membranes, including cell membranes, and so is absolutely essential for all
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U indicates the uncharged hydrophobic portion of the molecule, highlighted in blue.]]

Phospholipids are a class of lipids, and a major component of all biological membranes, along with glycolipids, cholesterol and proteins.
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Cholesterol is a sterol (a combination steroid and alcohol), a lipid found in the cell membranes of all tissues, and is transported in the blood plasma of all animals. Because cholesterol is synthesized by all eukaryotes, trace amounts of cholesterol are also found in membranes of
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Glycolipids are carbohydrate-attached lipids. Their role is to provide energy and also serve as markers for cellular recognition.

They occur where a carbohydrate chain is associated with phospholipids on the exoplasmic surface of the cell membrane.
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Surfactants, also known as tensides, are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.
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