The primary structure of a protein tells about

Options

A. 3D arrangement of all atoms
B. shape of poly peptide chain
C. specific sequence of amino acids
D. a3D arrangement of oligo peptide chains

Answer

### Step-by-Step Solution:

1. **Understanding Protein Structure**: Proteins have four levels of structure: primary, secondary, tertiary, and quaternary. Each level provides different information about the protein's composition and shape.

2. **Identifying the Primary Structure**: The primary structure of a protein refers specifically to the linear sequence of amino acids that make up the polypeptide chain. This sequence is determined by the genetic code and dictates how the protein will fold and function.

3. **Evaluating the Options**:
- **Option 1**: 3D arrangement of all atoms - This describes the tertiary or quaternary structure, not the primary structure.
- **Option 2**: Shape of polypeptide chain - This refers to the tertiary structure, which is the overall 3D shape of a single polypeptide.
- **Option 3**: Specific sequence of amino acids - This directly describes the primary structure of a protein.
- **Option 4**: 3D arrangement of oligopeptide chains - This relates to the tertiary or quaternary structure, not the primary structure.

4. **Conclusion**: The correct answer is the specific sequence of amino acids, as it is the defining characteristic of the primary structure of a protein.

### Final Answer:
The primary structure of a protein tells about the **specific sequence of amino acids**.

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