Amino acid

 Amino Acids 

  Human body if full of large molecules called biomolecules . Biomolecule is termed as molecules present in some living organisms. It includes large macromolecules such as protiens, carbohydrates, lipids and nucleic acids.

   Most of the biomolecules are polymers :

  Polymers are the large molecules madeup of many a small basic units called monomers.

 Amino acids are type of monomers. They join togeth er to form large molecule we called Protiens.

Amino acid

    Amino acid are organic and difunctional compounds having one or more amino groups (-NH2)  in the molecule. 

    The elements contains in amino acids are Hydrogen, Nitrogen, Oxygen, Carbon and other elements in side change group. There are about 500 and more naturally occurring amino acids. 
 Below structure is of Alanine.

   

 Amino acids are classified in several ways. Such as in Aliphatic, Aromatic, Cyclic, Acidic, Basic and Neutral ,.etc. 

  They are also classified as α, β, γ,etc according to the relative position of the two functional groups.

The α-amino acid are most important as they form peptides, proteins and enzymes.

 Essential Amino acids

     As we know amino acids are type of monomers. They combine to form large complex molecules. They form liner polyamides like proteins. 

Proteins are very essential to life for proper growth and metabolism in the body. There are among 250 natural α-amino acids known, only 20 amino acids occurs commonly in proteins.

   Many higher animals are unable to synthesize all the 20 amino acid to form proteins in diet. It is necessary to have all the amino acid to form proteins. Among 20 amino acids only 10 amino acids can be synthesized by human body. The other 10 amino acids which have to be supplied to the body in form of their diet are called as essential amino acids.

Amino acids combines to form a large molecules of proteins. But how does the amino acid gets polarised ?

Amino acids contains both a basic amino group and an acidic carboxyl group, they undergo an intramolecular acid-base reaction.

In amino acids, the amino group is prototaned to form cationic form of amino acids. 

The carboxyl group is deprotonated to form anionic form of amino acids. 

In equilibrium, the proton from the carboxyl group is combined with amino group of the amino acid. Since it contains both positive and negative charges and hence are called dipolar ions or zwitter ions.

The Amino acid present depends on the pH of solution and on the nature of the amino acid. In acid solution an amino acid is prototaned and exists in its cationic form. In basic solution an amino acid is deprotonated and exists in its anionic form. And in the neutral solutions it exists in zwitterionic form as intramolecular acid-base reaction takes place in amino acid.

In following video there is explanation of amino acid in video form.