The bonds in protein structure, that are not broken on denaturation , are :

Options

A. Hydrogen bonds
B. peptide bonds
C. ionic bonds
D. disulphide bonds

Answer

To answer the question regarding which bonds in protein structure are not broken during denaturation, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Protein Structure**:
- Proteins are made up of long chains of amino acids linked together by peptide bonds. These chains can fold into complex structures (primary, secondary, tertiary, and quaternary).

2. **Identifying Types of Bonds**:
- **Peptide Bonds**: These are covalent bonds that link amino acids together. They are formed between the carboxyl group of one amino acid and the amino group of another.
- **Hydrogen Bonds**: These are weaker interactions that help stabilize the secondary, tertiary, and quaternary structures of proteins.
- **Ionic Bonds**: These occur between charged side chains of amino acids and are also weaker than covalent bonds.
- **Disulfide Bonds**: These are covalent bonds formed between the sulfur atoms of cysteine residues, but they can be broken under certain conditions.

3. **Denaturation Process**:
- Denaturation is the process where proteins lose their three-dimensional structure due to external stressors like heat or changes in pH. During this process, weaker bonds (hydrogen, ionic, and disulfide bonds) are broken.

4. **Identifying Bonds That Remain Intact**:
- The peptide bonds, being covalent bonds, are much stronger than the other types of bonds mentioned. They remain intact during denaturation, meaning the primary structure of the protein (the sequence of amino acids) is preserved.

5. **Conclusion**:
- The bonds in protein structure that are not broken during denaturation are **peptide bonds**.

### Final Answer:
The bonds in protein structure that are not broken on denaturation are **peptide bonds**.

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