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Chemistry Question 68 – JEE-MAIN 2026

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Identify the incorrect statement about tertiary structure of proteins.

Recall the different levels of protein structure and the forces that stabilize each level.

Step 1: Understand Tertiary Structure Stabilization✦ Active

The tertiary structure of a protein is its overall three-dimensional shape, formed by the folding of secondary structures. It is stabilized by various interactions between the R-groups of amino acids, including hydrogen bonds, ionic bonds (electrostatic forces), hydrophobic interactions (van der Waals forces), and covalent disulfide bridges.

Step 2: Analyze the Effect of pH Changes○ Expand

Changes in pH affect the ionization state of acidic and basic amino acid side chains. This alters the charges on these groups, thereby disrupting the ionic bonds and hydrogen bonds that are crucial for maintaining the specific three-dimensional conformation of the tertiary structure. Extreme pH values can lead to denaturation, where the protein loses its native structure and biological activity.

💡 Teacher's Secret Hint

Remember that ionic and hydrogen bonds are sensitive to changes in proton concentration.

Step 3: Identify the Incorrect Statement○ Expand

Based on the analysis, the statement 'The structure remains intact when exposed to pH changes' is incorrect. pH changes cause alterations in the stabilizing forces, leading to the disruption of the tertiary structure (denaturation).

💡 Teacher's Secret Hint

Review the conditions that cause protein denaturation, such as extreme pH, temperature, and certain chemicals.

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