Denaturation of proteins leads to loss of its biological activity by

Options

A. formation of amino acids
B. loss of primary structure
C. loss of both primary and secondary structure
D. loss of both secondary and tertiary structure

Answer

**Step-by-Step Solution:**

1. **Understanding Denaturation**: Denaturation of proteins refers to the process where proteins lose their native structure, which is crucial for their biological function. This process can be triggered by various factors such as changes in temperature, pH, or exposure to chemicals.

2. **Protein Structure Levels**: Proteins have four levels of structure: primary, secondary, tertiary, and quaternary. The primary structure is the sequence of amino acids, while secondary and tertiary structures involve folding and interactions between the amino acids.

3. **Impact on Structure**: During denaturation, the secondary (alpha-helices and beta-sheets) and tertiary structures (3D shape) of the protein are disrupted. This disruption occurs due to the breaking of non-covalent interactions such as hydrogen bonds, ionic bonds, and hydrophobic interactions, which stabilize these higher-order structures.

4. **Primary Structure Remains Intact**: Importantly, the primary structure, which is the sequence of amino acids linked by peptide bonds, remains unchanged during denaturation. The peptide bonds are not broken in this process.

5. **Conclusion**: Therefore, denaturation leads to the loss of biological activity because the protein can no longer maintain its functional shape. The correct answer to the question is that denaturation results in the loss of both secondary and tertiary structures, while the primary structure remains intact.

**Final Answer**: Denaturation of proteins leads to the loss of biological activity by causing the loss of both secondary and tertiary structures.

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