what is classification of Lipids? what are the uses of lipids? uses of lipids? what type of classification of Lipids?


Lipids are heterogeneous group of biomolecules pairing in different functional groups.

Due to heterogeneity in the chemical nature lipids are defined based on two common physical properties.

These are hydrophobic and insoluble in h2o they required plasma lipoproteins for the transport {ketone bodies are exception because they are relatively soluble in h2 o2}

Classification of lipids:-

Lipids can be classified into 8 distinct types based on their chemical nature

Classification of lipids,lipids
Classification of lipids

Fatty acids:-

long chain carboxylic acids having 10 or more chains are considered as fatty acids milk of them contains short chain fatty acids 6 to 10 carbon atoms.

Most commonly occurring fatty acids in biological system contain even number of carbon atoms, that is because the fatty acids biosynthesis proceeds  with the addition of two carbon acetyl units so that the resultant molecule will have even number of carbon atoms.

Fatty acids are broadly divided into saturated and unsaturated fatty acids based on presence or absence of the double bonds.

Saturated fatty acid lack double bonds they are capable of compact packing therefore they have higher melting points compared to understand fatty acids having the same length.

Among the saturated fatty acids the melting point gradually increases with an  increase of carbon atoms.

Saturated fatty acids containing 16 to 20 carbon atoms are abundantly found in biological system.

cis fatty acids,trans fatty acids
fatty acids

Melting point of saturated fatty acids:-

Steraic acid is greater than palmitic acid greater than mynstic acid greater than lauric acid

 an unsaturated fatty acids contains one or more double bonds the unsaturation in fatty acids exhibits the following property.

Unsaturation  will be as usually cis nature each cis unsaturation causes a deformation in the molecule so that the compact packing  can’t occur for this reason unsaturated fatty acids have lesser melting point compared to saturated fatty acids having the  same  chain length.

The melting point for the decrease with increase in the number of unsaturation in fatty acids.

The trans bonds  allow the compact packing of unsaturated fatty acids and therefore  trans fatty acids will  have more melting point compared to cis fatty acid.


Porthyrins are a group of pigments they occur in animal and plants tissues these possess heterocyclic structure formed from four pyrol rings linked by 4 methylene groups.


Haemoglobin is the red pigment of blood.

It is chromopectin in which the prosthetic group is iron containing complex compound called haemoglobin.

Iron is an essential constituent of haemoglobin which oxygen  from lungs to other body tissues.

The importantance of hemoglobin is due to its capacity to combine reversibly with oxygen, it readily combines with oxygen to form unstable oxyhaemoglobin.

                          hb + 4o2 ↔ hb{o2}4

Haemoglobin acts as carrying career of oxygen from the organs of respiration tissues.

Carbon monoxide is highly poisonous its poisonous nature can be explained as it combines with haemoglobin to form carboxyhaemoglobin.

Carboxyhemoglobin is more stable than haemoglobin.


    hb + co → carboxyhemoglobin

Hemoglobin is very effective buffer. The buffering capacity is due to the presence of histidine residues in the globin fraction it isoelectric point is 6.8 it contains the ph of blood.

Weak acids and weak  alkalis acts on haemoglobin by repeating heam from global.

It also meant the viscosity of blood.


The chlorophyll ring system is a porphrin which one double bond in one of the pyroll ring has been reduced.

chlorophyll ring

A fused cyclo pentane ring is also present.

Chlorophyll absorbs low energy light in the far red region [700 nanometres].

Chlorophyll is also behaves as phosphoricent.

The presence of a metal atom is necessary in order that phosphorescence, takes place.

Chlorophyll is a green pigment present in chloroplast which are green coloured bodies inside the plant cells.

Chloroplast  are photosynthetically active.

The chlorophyll absorbs radiant energy and distributes it to the cell body.

chlorophyll absorbs radiant energy
chlorophyll absorbs radiant energy

The primary function of chloroplast is photosynthesis by which light energy is converted into chemical energy.

In this process carbohydrates are synthesized from carbon dioxide and hydrogen.



Glycerol esterified  with fatty acids which may be similar and dissimilar, these are the most abundant neutral lipids of constituent up to 90% of the total dietary lipids.

In a triacyl glycerol 3 fatty acid molecules esterified to glycerol maybe similar and dissimilar.

The c-1 fatty acid in a tag will be as usually saturated [palmitate,stearte] c2 fatty acid will be polysaturated [arachidonic acid linoleic acid] the c-3 fatty acids will be esterified with either saturated or unsaturated fatty acids.

Triglycerides are hydrolysed by hormone sensitive lipase present in the adipose tissue.

Insulin is the negative regulator of hormone sensitive lipase and there by inhibits the enzyme preventing lipolysis.


The alkyl hydrolysis of fat or oil resulting in the formation of soap is called saponification.


Soaps are salts of fatty acid with sodium[or] potassium unlike the fatty acids the soaps are soluble in water.

The fraction that enters in to aqueous phase after saponification is called saponifiable fraction. It includes glycerol of soaps.

Saponification number is defined as mg of standard koh [0.5n] required for the saponification of one gram of fat.

The quality of that fat increases with increase in the saponification number.

Halogenations [or] iodination:-

Fatty acids containing unsaturation can be subjected to halogenator or iodination ,the double bond reason is the target side for iodination.

The commonly used iodinating agents are  icl & ibr.

The degree of iodination of a fat depends on the proportion of ufas it contains and is expressed as in terms of iodine number.

Iodine number of fat lacking unsaturated fatty acid is zero.

Iodine nor increases with increase in the proportion of unsaturation in the fatty acids present in a fat.

Leave a comment