Lipid and Fat : role , classification , test and disorder

 

    Lipid & Fat

Lipid is defined as a substance that is i soluble in water and soluble in alcohol , ether , and chloroform . Lipid are an important of living cell together with carbohydrates and protein .lipid are main constituent of plant and animal . Lipid are easily stored in the body they serve as a source of fuel and an important constituent of the structure of cell.

              Lipid include fatty acid  , neutral fat waxes and steroid (e.g. Cortisone) lipid togather with carbohydrates and protein and nucleic acid are one of the major classes of biologically essential . Organic molecule found in all living role biologically such as membrane formation , cell division . Lipid are made from the alcohol glycerol (C₃H₈O₃).

          

  Over the 10000 kinds of lipid has been discovered.

Role of Lipid

Fat is the major contribution to energy from diet . Supplying 35-40 % food energy . Lipid play Several role in organism lipid make up protective barrier. lipid provide energy storage in animal and plant . Lipid make up not only plasma membrane but also cellular components such as nuclear involved. E.R. (endoplasmic reticulum) , golgi operates , mitochondria . Lipid provide the greatest amount of energy from consumption having more than twice . The amount of energy as protein and carbohydrates. 

           Lipid are essential for growth a healthy immune system and reproduction .

Lipid allow the body to store vitamin in the liver such as fat soluble vitamin A , D , E , K .

Classification of lipid

It may be classified on their physical property at room temperature  but preferable classification it's based on their structure .

          Based on structure they can be classified in three major category.

*Simple lipid

*Complex lipid

*Derived lipid

* Simple lipid

They are two types-

A. Fat and acid

B. Waxes

A. Fat and acid

The triesters of fatty acid with glycerol composed the classes of lipid known as fat and oil . These triglyceride [(C₃O₈O₃)₃] are found in both plant and animal and composed one of the major food group of our diet triglyceride are solid and semi solid at room temperature are classified as fat. 

* they are found in natural and large quantity. 

*They are best reserve material of food in the body. 

*They Act at insulator for the loss of body heat. 

*They act as a packing material for protecting internal organ.

H₂C----OCO[CH₂]₁₀CH₃

     |

H₂C----OCO[CH₂]₁₀CH₃

     |

H₂C----OCO[CH₂]₁₀CH₃

         Trilaurin      (mp - 45°C )

     

B. Waxes

A substance that is secreted by bees and it used by them for construction The honeycomb. Waxes are also lipat and they generally consists of long-chain ester which are made from long chain of alcohol natural wax are mixture of ester and also contain hydro hydrocarbon .

H₃C[CH₂]₁₄CO₂----[CH₂]₁₅CH₃

     |

H₃C[CH₂]₂₄CO₂----[CH₂]₂₉CH₃

     |

H₃C[CH₂]₃₀CO₂----[CH₂]₃₃CH₃

     

        ↓                         ↓

Carboxylic            alcohol

  Group

*Complex lipid

Compound lipids are contain ester of fatty acid with alcohol and other additional group. Phospholipid are glycerol in addition to a phosphoric acid nitrogen base and other substance.

  

A. Phospholipid 

They are the class of lipid that are major component of cell membrane they can form lipid bilayer because of their amphiphilic  character (surfactants such as soap and detergent).

B. Glycolipid

Glycolipid are lipid  with carbohydrate are attached. glycosidic Bond they play a major role in maintaining the stability of cell membrane which is important to the immune system and the connection that allowed to connect one to another from tissue.

* glycolipid are attach mono or oligo saccharide .

* It play whole serve as Marker for Cell to cell communication and provide the energy.

*Derived lipid

A. Fatty acid

The common feature of the liquid that they are all estar are formed long-chain fatty acid normally are saturated or unsaturated . The saturated fatty acid have higher melting point and unsaturated fatty acid are corresponding size.

   

    Fatty acid are long chain of lipid carboxylic acid found in fat and oil in cell membrane.

     Fatty acid come from animal and vegetable fat and oil the fatty acid play role outside the body they are used in lubricant in cooking and foot and production of soap, detergent ,cream and cosmetics.

B. Alcohol

Alcohol from into different class depending on the low alcohol group position on the chain of carbon atom. glycerol is a chemical compound also called glycerine or glycerine it is colourless , odourless , viscosity liquid that is widely used Pharmaceutical formation.

C. Steroid

Steroid is a terpinoids lipid characterized by a carbon skeleton with four fused ring steroid is one of the large group of chemical substances classified by a specific carbon structure , steroid including drug used to relieve swelling and inflammation Such as a Prednisone and cortisone group (prednisolone and deflozacart )Vitamin D and some sex hormone such as testosterone and estrogen.

     

      

Quantitative test

Sudan 3rd test

Take 0.5 ml ether or chloroform in a clean test tube and add 0.5 ml sample drop by drop till the sample is fully dissolved add one drop of sudan 3rd Reagent then red colour are produced.

Acrolein test

Take 0.5 gram powder of sodium bisulphate or potassium bisulphate in clean test tube then add 3 to 4 drop of sample mix well and heat it an irritating of smell of acrolein is produced.

Emulsifying testing

Take 3 ml sample in test tube and 2 drop of oleic acid then shake well and 2 drop of mixture to another test tube containing 3 ml 10% of caustic soda then emulsion is formed.

Disorder of lipid metabolism

gaucher's disease

Gorgeous disease is a rare genetic disorder characterized by the deposition of  glucocerebroside (a lipid composed of care mid acid glucose). Gauchers disease is most common lipidosis. The disease is the most in East European gauchers disease cause to an enlarged liver on spleen and brownish pigmentation of the skin.

         Storage of glycocerebroside in the eye can yellow spot.

        Storage in the bone marrow can pain and destroy bone.

Tay-Sachs disease

This disease is a rare disorder passed from parent to child 3 to 6 month it is caused by absence of an enzyme that breaks down fatty substances this fatty substance called gauchers side wild up toxic level in the child brain and effect on the nerve cell. 

 the child loss mude control blindness , paralysis and de

 

niemann pick disease

This disease is inherited diseases that affect lipat metabolism the way of fat lipid and cholesterol are stored in our body this disorder have an abnormal lipid metabolism that cause a build up harmful amount of lipid such as liver, spleen ,brain ,bone marrow.

Walman's disease

This disease or disorder that result when specific type of cholesterol and glyceroid are stored in tissue this disease caused in largement of liver and spleen.