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JEE Main · 2026 · 05 Apr 2026 · Shift 2 · Biomolecules

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Identify the incorrect statement about tertiary structure of proteins.
  1. (A)They can be fibrous or globular in structure.
  2. (B)The main forces that stabilize the structure are hydrogen bonding, disulphide links, van der Waals and electrostatic forces of attraction.
  3. (C)The structure remains intact when exposed to pH changes.✓ Correct
  4. (D)A linear polypeptide chain will convert to a secondary structure and then further folding of the secondary structure will convert to tertiary structure.

Answer: (C)

Solution

A protein's tertiary structure may be fibrous or globular, is held together by hydrogen bonding, disulphide links, van der Waals forces and electrostatic interactions, and arises when a polypeptide first forms secondary elements that fold further into the three-dimensional shape; these statements are all correct. A change in pH alters the ionisation of the side chains, breaking the electrostatic and hydrogen-bonding interactions and denaturing the fold, so the structure does not remain intact on exposure to pH changes. The incorrect statement is that the structure remains intact when exposed to pH changes.

JEE Main · 2026 · 05 Apr 2026 · Shift 2 · Single correct option

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