How does exposure to extreme pH (either high or low) affect the tertiary structure of a protein?

• A. It causes the primary structure to break down into individual amino acids.
• B. It disrupts ionic and hydrogen bonds, leading to denaturation of the protein.
• C. It strengthens disulfide bonds, making the protein more stable.
• D. It has no significant effect on the protein's tertiary structure.

Answer: (B)

Verified step by step guidance

1. Understand the concept of protein tertiary structure: The tertiary structure of a protein is the three-dimensional arrangement of its polypeptide chain, stabilized by various interactions such as hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bonds.
2. Recognize the role of pH in protein stability: Extreme pH levels (either very high or very low) can alter the ionization state of amino acid side chains, particularly those involved in ionic and hydrogen bonding.
3. Explain how ionic bonds are affected: At extreme pH, the charges on amino acid side chains may change, disrupting ionic bonds that contribute to the protein's tertiary structure.
4. Discuss the impact on hydrogen bonds: Extreme pH can also interfere with hydrogen bonding by altering the protonation state of functional groups, further destabilizing the protein's structure.
5. Conclude with denaturation: The disruption of ionic and hydrogen bonds due to extreme pH leads to the unfolding or denaturation of the protein, which compromises its tertiary structure and functionality.