On analysis of a protein chain , it was found that it is made up of just a peptide bond. The possible structure of the protein is its

Options

A. primary structure.
B. secondary structure.
C. tertiary structure.
D. quaternary structure.

Answer

To solve the question regarding the structure of a protein that consists solely of peptide bonds, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Protein Structure**: Proteins can have four levels of structure: primary, secondary, tertiary, and quaternary. Each level is characterized by different types of bonds and arrangements.

2. **Identifying the Primary Structure**: The primary structure of a protein is defined as the sequence of amino acids linked together by peptide bonds. This structure is linear and does not involve any other types of bonds.

3. **Examining Other Structures**:
- **Secondary Structure**: This involves the folding or coiling of the polypeptide chain into structures such as alpha helices or beta sheets, stabilized by hydrogen bonds.
- **Tertiary Structure**: This is the three-dimensional shape formed by the folding of the secondary structure, which can involve various types of bonds (hydrogen, ionic, covalent).
- **Quaternary Structure**: This structure involves multiple polypeptide chains coming together, also stabilized by various bonds.

4. **Analyzing the Given Information**: The question states that the protein chain is made up of just a peptide bond. This indicates that there are no additional types of bonds or folding present.

5. **Conclusion**: Since the protein consists solely of peptide bonds and does not exhibit any secondary, tertiary, or quaternary structures, it must be in its primary structure.

### Final Answer:
The possible structure of the protein is its **primary structure**.

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