question_answer 20)

Define the following as related to proteins. (i) Peptide linkage (ii) Primary structure (iii) Denaturation.  

Answer:

(i) Peptide linkage Peptide linkage is an amide linkageformed between  group end group.When carboxyl group of one amino acid reacts with the aminogroup of the other, a water molecule is eliminated and peptidelinkage is formed. (ii) Primary stricture Each polypeptide in a protein, has amino acidslinked with each other in a specific sequence and this sequence ofamino acids is called primary structure of that particular protein. Any change in the primary structure creates different protein. (iii) Denaturatiom When a protein in its native form, is subjected tophysical change as change in temperature, or chemical changelike change in pH, the hydrogen bonds are disturbed. The proteinglobules unfold, helix get uncoiled and protein loses its biologicalactivity. This is called denaturation of protein. Secondary andtertriary structures are destroyed but the primary structureremains as such. For example, coagulation of egg while on boiling,curdling of milk etc.