The first amino acid in the primary structure of the Protein is placed in

Options

A. right end
B. left end
C. middle
D. right end and left end

Answer

To solve the question regarding the placement of the first amino acid in the primary structure of a protein, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Amino Acids**:
- Amino acids are the building blocks of proteins. Each amino acid contains an amino group (NH2), a carboxylic acid group (COOH), and a variable side chain (R group).

2. **Defining Primary Structure**:
- The primary structure of a protein refers to the linear sequence of amino acids linked together by peptide bonds.

3. **Formation of Peptide Bonds**:
- When amino acids link together, they form peptide bonds through a condensation reaction, which involves the removal of a water molecule. This bond connects the carboxyl group of one amino acid to the amino group of another.

4. **Orientation of the Protein Structure**:
- In a polypeptide chain, the amino group (N-terminal) is located at one end, while the carboxyl group (C-terminal) is at the other end.

5. **Identifying the First Amino Acid**:
- The sequence of amino acids in a protein starts from the N-terminal end (the left end) and proceeds to the C-terminal end (the right end). Therefore, the first amino acid in the primary structure is always positioned at the N-terminal end.

6. **Conclusion**:
- Based on the above understanding, the first amino acid in the primary structure of the protein is placed at the left end.

### Final Answer:
The first amino acid in the primary structure of the protein is placed in the **left end**.