Statement I: Disruption of the natural structure of proteins is called denaturation.
Statement II: The coagulation of egg white on boiling is due to denaturation of proteins.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
A change in temperature or pH disturbs the hydrogen bonds that hold a native protein in shape, and the protein loses its biological activity.
Statement I: Disruption of the natural structure of proteins is called denaturation. — True. This loss of the native structure is called denaturation.
Statement II: The coagulation of egg white on boiling is due to denaturation of proteins. — True. Boiling (a change in temperature) unfolds the egg-white proteins, which then coagulate; this is a common example of denaturation.
Why Statement II does not explain Statement I?
Statement I is a definition of denaturation.
Statement II only gives one example of it; an example does not explain why the disruption of protein structure is called denaturation.
NCERT (2026-27 edition):
10.2.4 Denaturation of Proteins – “… When a protein in its native form, is subjected to physical change like change in temperature or chemical change like change in pH, the hydrogen bonds are disturbed. Due to this, globules unfold and helix get uncoiled and protein loses its biological activity. This is called denaturation of protein. During denaturation secondary and tertiary structures are destroyed but primary structure remains intact. The coagulation of egg white on boiling is a common example of denaturation.”