In the primary structure of a protein , amino acids are linked due to the presence of

Options

A. Hydrogen bonds
B. Peptide bonds
C. `-S-S-` linkages
D. lonic bonds

Answer

To solve the question regarding the primary structure of a protein and how amino acids are linked, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Protein Structure**:
- Proteins are made up of long chains of amino acids. The sequence and structure of these amino acids determine the protein's function.

2. **Identifying the Primary Structure**:
- The primary structure of a protein refers to the linear sequence of amino acids in a polypeptide chain. It is the simplest level of protein structure.

3. **Linkage of Amino Acids**:
- Amino acids are linked together in the primary structure by a specific type of bond. This bond is crucial for forming the polypeptide chain.

4. **Types of Bonds**:
- The options provided in the question mention various types of bonds: hydrogen bonds, sulfide bonds, di-sulfide linkages, and ionic bonds. However, these are not responsible for linking amino acids in the primary structure.

5. **Identifying the Correct Bond**:
- The bond that links amino acids in the primary structure is called a **peptide bond**. This bond forms between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water (a dehydration reaction).

6. **Conclusion**:
- Therefore, in the primary structure of a protein, amino acids are linked due to the presence of **peptide bonds**.

### Final Answer:
In the primary structure of a protein, amino acids are linked due to the presence of **peptide bonds**.

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