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JEE Main 2026 Apr 5 Shift 2, Chemistry Q18: Proteins

JEE Main2026Apr 5, Shift 2Chemistry
Q.

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.

  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.

Solution

The tertiary structure is held together by several weak interactions (H-bonding, electrostatic, van der Waals) plus disulphide bridges. These are sensitive to pH: protonation or deprotonation of side chains disrupts salt bridges and H-bonds, causing denaturation. So statement (3) is incorrect.

The others are standard facts about tertiary structure.

Concept behind this question

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