(i)
(ii) When the soluble form of proteins such as globular proteins is subjected to the action of heat, acids, alkalies or electrolytes, they undergo coagulation to form fibrous proteins which are insoluble in water. This results in to change of physical and biological properties of the proteins. The coagulated protein thus obtained is called denatured protein.
(iii) Nitrogen base residue present in DNA: Purine bases: Adenine, Guanine Pyrimidine bases: Cytosine, Thymine.
