Are phospholipids organic or inorganic

Are phospholipids organic or inorganic DEFAULT

Every cell contains high levels of inorganic phosphate ions (-PO43-). Sometimes one of the fatty acids in a triglyceride is replaced by a phosphate group to form a phospholipid. Phospholipid molecules have a hydrophilic region around the phosphate group which is soluble in water and hydrophobic regions around the fatty acids which are not soluble and repel water. This is a key element in the structure of cell membranes and so in the nature of life itself.

Structure of a phospholipid

Structure of a phospholipid – the hydrophilic and hydrophobic regions of the molecule have a major effect on the structure of cell membranes

Leaf with water droplets

Waxes are lipids made up of very long chain fatty acids joined to alcohols by ester bonds that are insoluble in water but soluble in organic polar solvents. The big difference between waxes and triglycerides is that in waxes there is only one fatty acid joined to a single alcohol, because alcohols only have one available hydroxyl group, unlike glycerol which had three. Waxes on the surface of leaves and insect cuticles, along with oils on feathers and fur, form a water-proof layer which enables the organisms to survive in their environments.

The waterproof waxy layer of a leaf stops water getting into or out of the plant cells underneath

Steroids are insoluble in water but otherwise are not typical lipids – they are made up of large numbers of carbon atoms arranged in complex ring structures. They are very important in biological systems as hormones.

Other lipids or lipid-derived molecules which are important in biological systems include:

Polar bear in the arctic

Blubber beneath the skin of a polar bear helps it keep warm and provides buoyancy for swimming. (Photo credit: Understanding Animal Research)

  • Carotenoids - are involved in photosynthesis
  • Lipid-rich myelin – found wrapped around neurones providing electrical insulation which makes rapid transmission of impulses possible
  • Fat in the bodies of animals acts to protect and cushion internal organs and gives thermal insulation (e.g. blubber in seals and polar bears).


For years the scientific evidence suggested saturated fats in the diet increased the risk of coronary heart disease. A recent massive study throws doubt on this.

Investigate this using a variety of sources (for example the internet, scientific journals or interviews with experts if you can). Then write two articles on the topic, one for a red-top newspaper and one to be published in New Scientist magazine. Consider the different audiences for each type of publication.

Sours: /topic/

Learning Objectives

  • Identify four types of organic molecules essential to human functioning
  • Explain the chemistry behind carbon’s affinity for covalently bonding in organic compounds
  • Provide examples of three types of carbohydrates, and identify the primary functions of carbohydrates in the body
  • Discuss three types of lipids important in human functioning
  • Describe the structure of proteins, and discuss their importance to human functioning
  • Identify the building blocks of nucleic acids, and the roles of DNA, RNA, and ATP in human functioning

Organic compounds typically consist of groups of carbon atoms covalently bonded to hydrogen, usually oxygen, and often other elements as well. Created by living things, they are found throughout the world, in soils and seas, commercial products, and every cell of the human body. The four types most important to human structure and function are carbohydrates, lipids, proteins, and nucleotides. Before exploring these compounds, you need to first understand the chemistry of carbon.

The Chemistry of Carbon

What makes organic compounds ubiquitous is the chemistry of their carbon core. Recall that carbon atoms have four electrons in their valence shell, and that the octet rule dictates that atoms tend to react in such a way as to complete their valence shell with eight electrons. Carbon atoms do not complete their valence shells by donating or accepting four electrons. Instead, they readily share electrons via covalent bonds.

Commonly, carbon atoms share with other carbon atoms, often forming a long carbon chain referred to as a carbon skeleton. When they do share, however, they do not share all their electrons exclusively with each other. Rather, carbon atoms tend to share electrons with a variety of other elements, one of which is always hydrogen. Carbon and hydrogen groupings are called hydrocarbons. If you study the figures of organic compounds in the remainder of this chapter, you will see several with chains of hydrocarbons in one region of the compound.  Many combinations are possible to fill carbon’s four “vacancies.” Carbon may share electrons with oxygen or nitrogen or other atoms in a particular region of an organic compound.

Carbon’s affinity for covalent bonding means that many distinct and relatively stable organic molecules nevertheless readily form larger, more complex molecules. Any large molecule is referred to as macromolecule (macro- = “large”), and the organic compounds in this section all fit this description. However, some macromolecules are made up of several “copies” of single units called monomer (mono- = “one”; -mer = “part”). Like beads in a long necklace, these monomers link by covalent bonds to form long polymers (poly- = “many”). There are many examples of monomers and polymers among the organic compounds.


The term carbohydrate means “hydrated carbon.” Recall that the root hydro- indicates water. A carbohydrate is a molecule composed of carbon, hydrogen, and oxygen; in most carbohydrates, hydrogen and oxygen are found in the same two-to-one relative proportions they have in water. In fact, the chemical formula for a “generic” molecule of carbohydrate is (CH2O)n.

Carbohydrates are referred to as saccharides, a word meaning “sugars.” Three forms are important in the body. Monosaccharides are the monomers of carbohydrates. Disaccharides (di- = “two”) are made up of two monomers. Polysaccharides are the polymers, and can consist of hundreds to thousands of monomers.


monosaccharide is a monomer, or building block, of carbohydrates. Examples of monosaccharides include:

  • glucose – the body’s main source of energy
  • fructose – a sweet sugar found in fruits
  • galactose – a sugar found in mild

Some of these monosaccharides in addition to others are shown in Figure 2.18a.

This figure shows the structure of glucose, fructose, galactose, deoxyribose, and ribose.

Figure 2.18. Five Important Monosaccharides


disaccharide is a pair of monosaccharides.  Three disaccharides (shown in Figure 2.19) are important to humans:

  • sucrose – commonly referred to as table sugar (glucose + fructose)
  • lactose – milk sugar (glucose + galactose)
  • maltose – or malt sugar (glucose + glucose)

As you can tell from their common names, you consume these in your diet; however, your body cannot use them directly. Instead, in the digestive tract, they are split into their component monosaccharides via hydrolysis.

This figure shows the structure of sucrose, lactose, and maltose.
Figure 2.19. Three Important DisaccharidesAll three important disaccharides form by dehydration synthesis.


Polysaccharides can contain a few to a thousand or more monosaccharides. Three are important to the body (Figure 2.20):

  • Starches – polymers of glucose that are stored in plants.  They are relatively easy to digest.
  • Glycogen – polymer of glucose that is stored in the tissues of animals, especially in the muscles and liver. It is not considered a dietary carbohydrate because very little glycogen remains in animal tissues after slaughter; however, the human body stores excess glucose as glycogen, again, in the muscles and liver.
  • Cellulose – polysaccharide that is the primary component of the cell wall of green plants, is the component of plant food referred to as “fiber”. In humans, cellulose/fiber is not digestible; however, dietary fiber has many health benefits. It helps you feel full so you eat less, it promotes a healthy digestive tract, and a diet high in fiber is thought to reduce the risk of heart disease and possibly some forms of cancer.
This figure shows the structure of starch, glycogen, and cellulose.
Figure 2.20. Three Important PolysaccharidesThree important polysaccharides are starches, glycogen, and fiber.

Functions of Carbohydrates

The body obtains carbohydrates from plant-based foods. Grains, fruits, and legumes and other vegetables provide most of the carbohydrate in the human diet, although lactose is found in dairy products.

Although most body cells can break down other organic compounds for fuel, all body cells can use glucose. Moreover, nerve cells (neurons) in the brain, spinal cord, and through the peripheral nervous system, as well as red blood cells, can use only glucose for fuel. In the breakdown of glucose for energy, molecules of adenosine triphosphate, better known as ATP, are produced. Adenosine triphosphate (ATP) is composed of a ribose sugar, an adenine base, and three phosphate groups. ATP releases free energy when its phosphate bonds are broken, and thus supplies ready energy to the cell. More ATP is produced in the presence of oxygen (O2) than in pathways that do not use oxygen. The overall reaction for the conversion of the energy in glucose to energy stored in ATP can be written:

(2.1)C6H12O6+ 6 O2→6 CO2+ 6 H2O + ATP

In addition to being a critical fuel source, carbohydrates are present in very small amounts in cells’ structure. For instance, some carbohydrate molecules bind with proteins to produce glycoproteins, and others combine with lipids to produce glycolipids, both of which are found in the membrane that encloses the contents of body cells.


lipid is one of a highly diverse group of compounds made up mostly of hydrocarbons. The few oxygen atoms they contain are often at the periphery of the molecule. Their nonpolar hydrocarbons make all lipids hydrophobic. In water, lipids do not form a true solution, but they may form an emulsion, which is the term for a mixture of solutions that do not mix well.


triglyceride is one of the most common dietary lipid groups, and the type found most abundantly in body tissues. This compound, which is commonly referred to as a fat, is formed from the synthesis of two types of molecules (Figure 2.21):

  • A glycerol backbone at the core of triglycerides, consists of three carbon atoms.
  • Three fatty acids, long chains of hydrocarbons with a carboxyl group and a methyl group at opposite ends, extend from each of the carbons of the glycerol.
This image shows the reaction for the formation of triglycerides.
Figure 2.21. TriglyceridesTriglycerides are composed of glycerol attached to three fatty acids via dehydration synthesis. Notice that glycerol gives up a hydrogen atom, and the carboxyl groups on the fatty acids each give up a hydroxyl group.

Fatty acid chains that have no double carbon bonds anywhere along their length and therefore contain the maximum number of hydrogen atoms are called saturated fatty acids. These straight, rigid chains pack tightly together and are solid or semi-solid at room temperature (Figure 2.22a). Butter and lard are examples, as is the fat found on a steak or in your own body. In contrast, fatty acids with one double carbon bond are kinked at that bond (Figure 2.22b). These unsaturated fatty acids are therefore unable to pack together tightly, and are liquid at room temperature.  Plant oils such as olive oil typically contain both mono- and polyunsaturated fatty acids.

This diagram shows the chain structures of a saturated and an unsaturated fatty acid.
Figure 2.22. Fatty Acid ShapesThe level of saturation of a fatty acid affects its shape. (a) Saturated fatty acid chains are straight. (b) Unsaturated fatty acid chains are kinked.


As a group, triglycerides are a major fuel source for the body. When you are resting or asleep, a majority of the energy used to keep you alive is derived from triglycerides stored in your fat (adipose) tissues. Triglycerides also fuel long, slow physical activity such as gardening or hiking, and contribute a modest percentage of energy for vigorous physical activity. Dietary fat also assists the absorption and transport of the nonpolar fat-soluble vitamins A, D, E, and K. Additionally, stored body fat protects and cushions the body’s bones and internal organs, and acts as insulation to retain body heat.



A phospholipid is a lipid that forms the plasma membrane in cells (Figure 2.23).  It is composed of a polar, phosphate “head” and a nonpolar, lipid “tail”.  The tail end of the molecule is hydrophobic and can interact with oil, and the other head-end is hydrophilic and can interact with water. This makes phospholipids ideal emulsifiers, compounds that help disperse fats in aqueous liquids, and enables them to interact with both the watery interior of cells and the watery solution outside of cells as components of the cell membrane.

This figure shows the chemical structure of different lipids.
Figure 2.23. Other Important Lipids(a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups.


Asteroid compound (referred to as a sterol) has as its foundation a set of four hydrocarbon rings bonded to a variety of other atoms and molecules (see Figure 2.23b). Although both plants and animals synthesize sterols, the type that makes the most important contribution to human structure and function is cholesterol, which is synthesized by the liver in humans and animals and is also present in most animal-based foods.  Cholesterol is an important component of bile acids, compounds that help emulsify dietary fats. In fact, the word root chole- refers to bile. Cholesterol is also a building block of many hormones, signaling molecules that the body releases to regulate processes at distant sites. Finally, like phospholipids, cholesterol molecules are found in the cell membrane, where their hydrophobic and hydrophilic regions help regulate the flow of substances into and out of the cell.


You might associate proteins with muscle tissue, but in fact, proteins are critical components of all tissues and organs. A protein is an organic molecule composed of amino acids linked by peptide bonds. Proteins include the keratin in the epidermis of skin that protects underlying tissues, the collagen found in the dermis of skin, in bones, and in the meninges that cover the brain and spinal cord. Proteins are also components of many of the body’s functional chemicals, including digestive enzymes in the digestive tract, antibodies, the neurotransmitters that neurons use to communicate with other cells, and the peptide-based hormones that regulate certain body functions (for instance, growth hormone). While carbohydrates and lipids are composed of hydrocarbons and oxygen, all proteins also contain nitrogen (N), and many contain sulfur (S), in addition to carbon, hydrogen, and oxygen.

Microstructure of Proteins

Proteins are polymers made up of nitrogen-containing monomers called amino acids. An amino acid is a molecule composed of an amino group and a carboxyl group, together with a variable side chain. Just 20 different amino acids contribute to nearly all of the thousands of different proteins important in human structure and function. Body proteins contain a unique combination of a few dozen to a few hundred of these 20 amino acid monomers. All 20 of these amino acids share a similar structure (Figure 2.24). All consist of a central carbon atom to which the following are bonded:

  • a hydrogen atom
  • an alkaline (basic) amino group NH2 (see Table 2.1)
  • an acidic carboxyl group COOH (see Table 2.1)
  • a variable group
This figure shows the structure of an amino acid.
Figure 2.24. Structure of an Amino Acid

Notice that all amino acids contain both an acid (the carboxyl group) and a base (the amino group) (amine = “nitrogen-containing”). For this reason, they make excellent buffers, helping the body regulate acid–base balance. What distinguishes the 20 amino acids from one another is their variable group, which is referred to as a side chain or an R-group. This group can vary in size and can be polar or nonpolar, giving each amino acid its unique characteristics. For example, the side chains of two amino acids—cysteine and methionine—contain sulfur. Sulfur does not readily participate in hydrogen bonds, whereas all other amino acids do. This variation influences the way that proteins containing cysteine and methionine are assembled.

Amino acids join via dehydration synthesis to form protein polymers (Figure 2.25). The unique bond holding amino acids together is called a peptide bond. A peptide bond is a covalent bond between two amino acids that forms by dehydration synthesis. A peptide, in fact, is a very short chain of amino acids. Strands containing fewer than about 100 amino acids are generally referred to as polypeptides rather than proteins.

This figure shows the formation of a peptide bond, highlighted in blue.
Figure 2.25. Peptide BondDifferent amino acids join together to form peptides, polypeptides, or proteins via dehydration synthesis. The bonds between the amino acids are peptide bonds.

Shape of Proteins

Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.26a).

This figure shows the secondary structure of peptides. The top panel shows a straight chain, the middle panel shows an alpha-helix and a beta sheet. The bottom panel shows the tertiary structure and fully folded protein.
Figure 2.26. The Shape of Proteins(a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues.

When proteins are exposed to extreme heat, acids, bases, and certain other substances, proteins will denature. Denaturation is a change in the structure of a molecule through physical or chemical means. Denatured proteins lose their functional shape and are no longer able to carry out their jobs. An everyday example of protein denaturation is the curdling of milk when acidic lemon juice is added.

The contribution of the shape of a protein to its function can hardly be exaggerated. For example, the long, slender shape of protein strands that make up muscle tissue is essential to their ability to contract (shorten) and relax (lengthen). As another example, bones contain long threads of a protein called collagen that acts as scaffolding upon which bone minerals are deposited. These elongated proteins, called fibrous proteins, are strong and durable and typically hydrophobic.

In contrast, globular proteins are globes or spheres that tend to be highly reactive and are hydrophilic. The hemoglobin proteins packed into red blood cells are an example (see Figure 2.26d); however, globular proteins are abundant throughout the body, playing critical roles in most body functions. Enzymes, introduced earlier as protein catalysts, are examples of this. The next section takes a closer look at the action of enzymes.

Proteins Function as Enzymes

If you were trying to type a paper, and every time you hit a key on your laptop there was a delay of six or seven minutes before you got a response, you would probably get a new laptop. In a similar way, without enzymes to catalyze chemical reactions, the human body would be nonfunctional. It functions only because enzymes function.

Enzymatic reactions—chemical reactions catalyzed by enzymes—begin when substrates bind to the enzyme. A substrate is a reactant in an enzymatic reaction. This occurs on regions of the enzyme known as active sites (Figure 2.27). Any given enzyme catalyzes just one type of chemical reaction. This characteristic, called specificity, is due to the fact that a substrate with a particular shape and electrical charge can bind only to an active site corresponding to that substrate.

This image shows the steps in which an enzyme can act. The substrate is shown binding to the enzyme, forming a product, and the detachment of the product.
Figure 2.27. Steps in an Enzymatic Reaction(a) Substrates approach active sites on enzyme. (b) Substrates bind to active sites, producing an enzyme–substrate complex. (c) Changes internal to the enzyme–substrate complex facilitate interaction of the substrates. (d) Products are released and the enzyme returns to its original form, ready to facilitate another enzymatic reaction.

Binding of a substrate produces an enzyme–substrate complex. It is likely that enzymes speed up chemical reactions in part because the enzyme–substrate complex undergoes a set of temporary and reversible changes that cause the substrates to be oriented toward each other in an optimal position to facilitate their interaction. This promotes increased reaction speed. The enzyme then releases the product(s), and resumes its original shape. The enzyme is then free to engage in the process again, and will do so as long as substrate remains.


The fourth type of organic compound important to human structure and function are the nucleotides (Figure 2.28). A nucleotide is one of a class of organic compounds composed of three subunits:

  • one or more phosphate groups
  • a pentose sugar: either deoxyribose or ribose
  • a nitrogen-containing base: adenine, cytosine, guanine, thymine, or uracil

Nucleotides can be assembled into nucleic acids (DNA or RNA) or the energy compound adenosine triphosphate.

This figure shows the structure of nucleotides.
Figure 2.28. Nucleotides(a) The building blocks of all nucleotides are one or more phosphate groups, a pentose sugar, and a nitrogen-containing base. (b) The nitrogen-containing bases of nucleotides. (c) The two pentose sugars of DNA and RNA.

Nucleic Acids

The nucleic acids differ in their type of pentose sugar. Deoxyribonucleic acid (DNA) is nucleotide that stores genetic information. DNA contains deoxyribose (so-called because it has one less atom of oxygen than ribose) plus one phosphate group and one nitrogen-containing base. The “choices” of base for DNA are adenine, cytosine, guanine, and thymine. Ribonucleic acid (RNA) is a ribose-containing nucleotide that helps manifest the genetic code as protein. RNA contains ribose, one phosphate group, and one nitrogen-containing base, but the “choices” of base for RNA are adenine, cytosine, guanine, and uracil.

The nitrogen-containing bases adenine and guanine are classified as purines. A purine is a nitrogen-containing molecule with a double ring structure, which accommodates several nitrogen atoms. The bases cytosine, thymine (found in DNA only) and uracil (found in RNA only) are pyramidines. A pyramidine is a nitrogen-containing base with a single ring structure

Bonds formed by dehydration synthesis between the pentose sugar of one nucleic acid monomer and the phosphate group of another form a “backbone,” from which the components’ nitrogen-containing bases protrude. In DNA, two such backbones attach at their protruding bases via hydrogen bonds. These twist to form a shape known as a double helix (Figure 2.29). The sequence of nitrogen-containing bases within a strand of DNA form the genes that act as a molecular code instructing cells in the assembly of amino acids into proteins. Humans have almost 22,000 genes in their DNA, locked up in the 46 chromosomes inside the nucleus of each cell (except red blood cells which lose their nuclei during development). These genes carry the genetic code to build one’s body, and are unique for each individual except identical twins.

This figure shows a double helix.
Figure 2.29. DNAIn the DNA double helix, two strands attach via hydrogen bonds between the bases of the component nucleotides.

In contrast, RNA consists of a single strand of sugar-phosphate backbone studded with bases. Messenger RNA (mRNA) is created during protein synthesis to carry the genetic instructions from the DNA to the cell’s protein manufacturing plants in the cytoplasm, the ribosomes.

Adenosine Triphosphate

The nucleotide adenosine triphosphate (ATP), is composed of a ribose sugar, an adenine base, and three phosphate groups (Figure 2.30). ATP is classified as a high energy compound because the two covalent bonds linking its three phosphates store a significant amount of potential energy. In the body, the energy released from these high energy bonds helps fuel the body’s activities, from muscle contraction to the transport of substances in and out of cells to anabolic chemical reactions.

This figure shows the structure of ATP.
Figure 2.30. Structure of Adenosine Triphosphate (ATP)

When a phosphate group is cleaved from ATP, the products are adenosine diphosphate (ADP) and inorganic phosphate (Pi). This hydrolysis reaction can be written: (2.2)ATP + H2O →ADP + Pi+ energy

Removal of a second phosphate leaves adenosine monophosphate (AMP) and two phosphate groups. Again, these reactions also liberate the energy that had been stored in the phosphate-phosphate bonds. They are reversible, too, as when ADP undergoes phosphorylation. Phosphorylation is the addition of a phosphate group to an organic compound, in this case, resulting in ATP. In such cases, the same level of energy that had been released during hydrolysis must be reinvested to power dehydration synthesis.

Cells can also transfer a phosphate group from ATP to another organic compound. For example, when glucose first enters a cell, a phosphate group is transferred from ATP, forming glucose phosphate (C6H12O6—P) and ADP. Once glucose is phosphorylated in this way, it can be stored as glycogen or metabolized for immediate energy.



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Phospholipid arrangement in cell membranes.

Phospholipids, also known as phosphatides,[1] are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group, and two hydrophobic "tails" derived from fatty acids, joined by a glycerol molecule. Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospholipid molecule.[2] The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine.

Phospholipids are a key component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. In eukaryotes, cell membranes also contain another class of lipid, sterol, interspersed among the phospholipids. The combination provides fluidity in two dimensions combined with mechanical strength against rupture. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science.[3]

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.

Phospholipids in biological membranes[edit]


The phospholipids are amphiphilic. The hydrophilic end usually contains a negatively charged phosphate group, and the hydrophobic end usually consists of two "tails" that are long fatty acid residues.

In aqueous solutions, phospholipids are driven by hydrophobic interactions that result in the fatty acid tails aggregating to minimize interactions with the water molecules. The result is often a phospholipid bilayer: a membrane that consists of two layers of oppositely oriented phospholipid molecules, with their heads exposed to the liquid on both sides, and with the tails directed into the membrane. That is the dominant structural motif of the membranes of all cells and of some other biological structures, such as vesicles or virus coatings.

Phospholipid bilayers are the main structural component of the cell membranes.

In biological membranes, the phospholipids often occur with other molecules (e.g., proteins, glycolipids, sterols) in a bilayer such as a cell membrane.[4] Lipid bilayers occur when hydrophobic tails line up against one another, forming a membrane of hydrophilic heads on both sides facing the water.


These specific properties allow phospholipids to play an important role in the cell membrane. Their movement can be described by the fluid mosaic model, that describes the membrane as a mosaic of lipid molecules that act as a solvent for all the substances and proteins within it, so proteins and lipid molecules are then free to diffuse laterally through the lipid matrix and migrate over the membrane. Sterols contribute to membrane fluidity by hindering the packing together of phospholipids. However, this model has now been superseded, as through the study of lipid polymorphism it is now known that the behaviour of lipids under physiological (and other) conditions is not simple.[citation needed]

Main phospholipids[edit]

Diacylglyceride structures[edit]

See: Glycerophospholipid


See Sphingolipid

  • Ceramide phosphorylcholine (Sphingomyelin) (SPH)
  • Ceramide phosphorylethanolamine (Sphingomyelin) (Cer-PE)
  • Ceramide phosphoryllipid


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. Liposomes are often composed of phosphatidylcholine-enriched phospholipids and may also contain mixed phospholipid chains with surfactant properties. The ethosomal formulation of ketoconazole using phospholipids is a promising option for transdermal delivery in fungal infections.[5] Advances in phospholipid research lead to exploring these biomolecules and their conformations using lipidomics.


Computational simulations of phospholipids are often performed using molecular dynamics with force fields such as GROMOS, CHARMM, or AMBER.


Phospholipids are optically highly birefringent, i.e. their refractive index is different along their axis as opposed to perpendicular to it. Measurement of birefringence can be achieved using cross polarisers in a microscope to obtain an image of e.g. vesicle walls or using techniques such as dual polarisation interferometry to quantify lipid order or disruption in supported bilayers.


There are no simple methods available for analysis of phospholipids since the close range of polarity between different phospholipid species makes detection difficult. Oil chemists often use spectroscopy to determine total Phosphorus abundance and then calculate approximate mass of phospholipids based on molecular weight of expected fatty acid species. Modern lipid profiling employs more absolute methods of analysis, with NMR spectroscopy, particularly 31P-NMR,[6][7] while HPLC-ELSD[8] provides relative values.

Phospholipid synthesis[edit]

Phospholipid synthesis occurs in the cytosolic side of ER membrane [9] that is studded with proteins that act in synthesis (GPAT and LPAAT acyl transferases, phosphatase and choline phosphotransferase) and allocation (flippase and floppase). Eventually a vesicle will bud off from the ER containing phospholipids destined for the cytoplasmic cellular membrane on its exterior leaflet and phospholipids destined for the exoplasmic cellular membrane on its inner leaflet.[10][11]


Common sources of industrially produced phospholipids are soya, rapeseed, sunflower, chicken eggs, bovine milk, fish eggs etc. Each source has a unique profile of individual phospholipid species as well as fatty acids and consequently differing applications in food, nutrition, pharmaceuticals, cosmetics and drug delivery.

In signal transduction[edit]

Some types of phospholipid can be split to produce products that function as second messengers in signal transduction. Examples include phosphatidylinositol (4,5)-bisphosphate (PIP2), that can be split by the enzyme Phospholipase C into inositol triphosphate (IP3) and diacylglycerol (DAG), which both carry out the functions of the Gq type of G protein in response to various stimuli and intervene in various processes from long term depression in neurons[12] to leukocyte signal pathways started by chemokine receptors.[13]

Phospholipids also intervene in prostaglandin signal pathways as the raw material used by lipase enzymes to produce the prostaglandin precursors. In plants they serve as the raw material to produce Jasmonic acid, a plant hormone similar in structure to prostaglandins that mediates defensive responses against pathogens.

Food technology[edit]

Phospholipids can act as emulsifiers, enabling oils to form a colloid with water. Phospholipids are one of the components of lecithin which is found in egg-yolks, as well as being extracted from soybeans, and is used as a food additive in many products, and can be purchased as a dietary supplement. Lysolecithins are typically used for water-oil emulsions like margarine, due to their higher HLB ratio.

Phospholipid derivatives[edit]

See table below for an extensive list.
  • Natural phospholipid derivates:
    egg PC (Egg lecithin), egg PG, soy PC, hydrogenated soy PC, sphingomyelin as natural phospholipids.
  • Synthetic phospholipid derivates:
    • Phosphatidic acid (DMPA, DPPA, DSPA)
    • Phosphatidylcholine (DDPC, DLPC, DMPC, DPPC, DSPC, DOPC, POPC, DEPC)
    • Phosphatidylglycerol (DMPG, DPPG, DSPG, POPG)
    • Phosphatidylethanolamine (DMPE, DPPE, DSPE DOPE)
    • Phosphatidylserine (DOPS)
    • PEG phospholipid (mPEG-phospholipid, polyglycerin-phospholipid, funcitionalized-phospholipid, terminal activated-phospholipid)

Abbreviations used and chemical information of glycerophospholipids[edit]

Abbreviation CAS Name Type
DEPA-NA80724-31-81,2-Dierucoyl-sn-glycero-3-phosphate (Sodium Salt)Phosphatidic acid
DEPG-NA1,2-Dierucoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Sodium Salt)Phosphatidylglycerol
DLPA-NA1,2-Dilauroyl-sn-glycero-3-phosphate (Sodium Salt)Phosphatidic acid
DLPG-NA1,2-Dilauroyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Sodium Salt)Phosphatidylglycerol
DLPG-NH41,2-Dilauroyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Ammonium Salt)Phosphatidylglycerol
DLPS-NA1,2-Dilauroyl-sn-glycero-3-phosphoserine (Sodium Salt)Phosphatidylserine
DMPA-NA80724-31,2-Dimyristoyl-sn-glycero-3-phosphate (Sodium Salt)Phosphatidic acid
DMPG-NA67232-80-81,2-Dimyristoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Sodium Salt)Phosphatidylglycerol
DMPG-NH41,2-Dimyristoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Ammonium Salt)Phosphatidylglycerol
DMPG-NH4/NA1,2-Dimyristoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Sodium/Ammonium Salt)Phosphatidylglycerol
DMPS-NA1,2-Dimyristoyl-sn-glycero-3-phosphoserine (Sodium Salt)Phosphatidylserine
DOPA-NA1,2-Dioleoyl-sn-glycero-3-phosphate (Sodium Salt)Phosphatidic acid
DOPG-NA62700-69-01,2-Dioleoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Sodium Salt)Phosphatidylglycerol
DOPS-NA70614-14-11,2-Dioleoyl-sn-glycero-3-phosphoserine (Sodium Salt)Phosphatidylserine
DPPA-NA71065-87-71,2-Dipalmitoyl-sn-glycero-3-phosphate (Sodium Salt)Phosphatidic acid
DPPG-NA67232-81-91,2-Dipalmitoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Sodium Salt)Phosphatidylglycerol
DPPG-NH473548-70-61,2-Dipalmitoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Ammonium Salt)Phosphatidylglycerol
DPPS-NA1,2-Dipalmitoyl-sn-glycero-3-phosphoserine (Sodium Salt)Phosphatidylserine
DSPA-NA108321-18-21,2-Distearoyl-sn-glycero-3-phosphate (Sodium Salt)Phosphatidic acid
DSPG-NA67232-82-01,2-Distearoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Sodium Salt)Phosphatidylglycerol
DSPG-NH4108347-80-41,2-Distearoyl-sn-glycero-3[Phospho-rac-(1-glycerol...) (Ammonium Salt)Phosphatidylglycerol
DSPS-NA1,2-Distearoyl-sn-glycero-3-phosphoserine (Sodium Salt)Phosphatidylserine
HEPCHydrogenated Egg PCPhosphatidylcholine
HSPCHydrogenated Soy PCPhosphatidylcholine
LYSOPC MYRISTIC18194-24-61-Myristoyl-sn-glycero-3-phosphocholineLysophosphatidylcholine
LYSOPC PALMITIC17364-16-81-Palmitoyl-sn-glycero-3-phosphocholineLysophosphatidylcholine
LYSOPC STEARIC19420-57-61-Stearoyl-sn-glycero-3-phosphocholineLysophosphatidylcholine
MilkSphingomyelin MPPC1-Myristoyl-2-palmitoyl-sn-glycero 3-phosphocholinePhosphatidylcholine
POPG-NA81490-05-31-Palmitoyl-2-oleoyl-sn-glycero-3[Phospho-rac-(1-glycerol)...] (Sodium Salt)Phosphatidylglycerol

See also[edit]


  1. ^"Phospholipid | biochemistry". Encyclopedia Britannica. Retrieved 2020-12-22.
  2. ^Burri, L.; Hoem, N.; Banni, S.; Berge, K. (2012). "Marine Omega-3 Phospholipids: Metabolism and Biological Activities". International Journal of Molecular Sciences. 13 (11): 15401–15419. doi:10.3390/ijms131115401. PMC 3509649. PMID 23203133.
  3. ^Mashaghi S.; Jadidi T.; Koenderink G.; Mashaghi A. (2013). "Lipid Nanotechnology". Int. J. Mol. Sci. 14 (2): 4242–4282. doi:10.3390/ijms14024242. PMC 3588097. PMID 23429269.
  4. ^Campbell, Neil A.; Brad Williamson; Robin J. Heyden (2006). Biology: Exploring Life. Boston, Massachusetts: Pearson Prentice Hall. ISBN .[page needed]
  5. ^Ketoconazole Encapsulated Liposome and Ethosome: GUNJAN TIWARI
  6. ^N. Culeddu; M. Bosco; R. Toffanin & P. Pollesello (1998). "High resolution 31P NMR of extracted phospholipids". Magnetic Resonance in Chemistry. 36 (12): 907–912. doi:10.1002/(sici)1097-458x(199812)36:12<907::aid-omr394>;2-5.
  7. ^Furse, Samuel; Liddell, Susan; Ortori, Catharine A.; Williams, Huw; Neylon, D. Cameron; Scott, David J.; Barrett, David A.; Gray, David A. (2013). "The lipidome and proteome of oil bodies from Helianthus annuus (common sunflower)". Journal of Chemical Biology. 6 (2): 63–76. doi:10.1007/s12154-012-0090-1. PMC 3606697. PMID 23532185.
  8. ^T.L. Mounts; A.M. Nash (1990). "HPLC analysis of phospholipids in crude oil for evaluation of soybean deterioration". Journal of the American Oil Chemists' Society. 67 (11): 757–760. doi:10.1007/BF02540486. S2CID 84380025.
  9. ^Prinz, William A.; Choudhary, Vineet; Liu, Li-Ka; Lahiri, Sujoy; Kannan, Muthukumar (2017-03-01). "Phosphatidylserine synthesis at membrane contact sites promotes its transport out of the ER". Journal of Lipid Research. 58 (3): 553–562. doi:10.1194/jlr.M072959. ISSN 0022-2275. PMC 5335585. PMID 28119445.
  10. ^Lodish H, Berk A, et al. (2007). Molecular Cell Biology (6th ed.). W. H. Freeman. ISBN .
  11. ^Zheng L, Lin Y, Lu S, Zhang J, Bogdanov M (November 2017). "Biogenesis, transport and remodeling of lysophospholipids in Gram-negative bacteria". Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids. 1862 (11): 1404–1413. doi:10.1016/j.bbalip.2016.11.015. PMC 6162059. PMID 27956138.
  12. ^Choi, S.-Y.; Chang, J; Jiang, B; Seol, GH; Min, SS; Han, JS; Shin, HS; Gallagher, M; Kirkwood, A (2005). "Multiple Receptors Coupled to Phospholipase C Gate Long-Term Depression in Visual Cortex". Journal of Neuroscience. 25 (49): 11433–43. doi:10.1523/JNEUROSCI.4084-05.2005. PMC 6725895. PMID 16339037.
  13. ^Cronshaw, D. G.; Kouroumalis, A; Parry, R; Webb, A; Brown, Z; Ward, SG (2006). "Evidence that phospholipase C-dependent, calcium-independent mechanisms are required for directional migration of T lymphocytes in response to the CCR4 ligands CCL17 and CCL22". Journal of Leukocyte Biology. 79 (6): 1369–80. doi:10.1189/jlb.0106035. PMID 16614259.
Organic vs Inorganic Compounds

I wanted to pretend that I hadn't noticed anything, but Eve and Christine stopped next to them and began to watch. The girl, noticing the audience, smirking lasciviously, lifted her skirt so that at close range it became clear to all of us how. The guy's penis, shiny with grease, was sinking into it.

Organic are inorganic phospholipids or

The saving oblivion did not come, so the young elf did not stop going over in her fevered mind, numerous plans of revenge. The night has come. Without coming up with anything better, the elf put on another short suit, grabbed a short dagger and decisively flew out of the room. Having reached the huge dwelling of the elders, who hates everything and all of Sindorel, she made her way inside, deftly bypassing the rare guards.

Difference between Organic and Inorganic Compounds

Therefore, the flag was originally yellow-blue, and not blue-yellow as it is now. From the kitchen I go with two cups: coffee for myself, green tea for her. Outside the window, rain is thrashing, passers-by are hiding under the visors, opening the flowers of the umbrellas.

Now discussing:

Let her go and went to the meeting. Dima, an acquaintance with a knife, went at me, from a couple of not dexterous movements of my hands, he deliberately released the knife. And after my light blows he fell down himself, we met eyes with my aunt.

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