Question

The bonds in protein structure, which are not broken on denaturation, are:
A.Hydrogen bonds
B.Peptide bonds
C.Ionic bonds
D.Disulphide bond

Answer 1

Hint: We must have to know that the protein structure in amino acid chain molecules are arranged in a three dimensional manner. The proteins are formed by the condensation reaction of amino acids. And during the condensation reaction there is a loss of water molecule and it will attach with the peptide bond. And the structure of protein in four types and that is, primary, secondary, tertiary and quaternary.

Complete answer:
The secondary structure of protein contains hydrogen bonds. And during the denaturation process, the intermolecular hydrogen bond will break. Hence, option (A) is incorrect.
The peptide bond is a chemical bond which occurs between the carboxyl groups of the two molecules. By the reaction of the amino group of one molecule with the carboxyl group of the other molecule, a release of water molecules will take place. During the denaturation process of protein, the secondary and tertiary structure of protein will be changed but the peptide bond of the primary structure remains constant. Because, the denaturation reaction is not strong and its energy is not enough to break the peptide bond.
During the denaturation reaction of proteins, the weak ionic bond will rupture. Hence, the option (C) is correct.
The disulphide bond is broken by adding of a reducing agent in the denaturation process. Hence, option (D) is incorrect.

Hence, the option (C) is correct.

Note:
We need to know that the peptide bond is present between two amino acids and it is a covalent chemical bond. And the important bonds present in protein is, hydrogen bond, peptide bond, disulphide bond and ionic bond. During the denaturation of proteins, there is a breakage of so many weak bonds like hydrogen bonds, which will take place. And these denatured proteins have more random structure and it is insoluble.