Protein is a polymer of

Options

A. Amino acid
B. `alpha ` - D - amino acid
C. `alpha` - L - amino acid
D. `beta` - amino acid

Answer

### Step-by-Step Text Solution:

1. **Understanding Proteins**:
- Proteins are essential biomolecules that play various roles in biological systems. They are involved in structure, function, and regulation of the body’s tissues and organs.

2. **Defining Polymers**:
- A polymer is a large molecule composed of repeating structural units (monomers) connected by covalent chemical bonds.

3. **Identifying the Monomer of Proteins**:
- The monomer units that make up proteins are called amino acids.

4. **Structure of Amino Acids**:
- Each amino acid has a central carbon atom (C) bonded to four different groups:
- An amino group (NH2)
- A carboxylic acid group (COOH)
- A hydrogen atom (H)
- A variable side chain (R group) that determines the specific properties of each amino acid.

5. **Formation of Peptide Bonds**:
- When amino acids link together to form proteins, they do so through a process called dehydration synthesis (or condensation reaction). In this process, a water molecule is released when the carboxylic group of one amino acid reacts with the amino group of another, forming a covalent bond known as a peptide bond.

6. **Resulting Structure**:
- The resulting chain of amino acids forms a polypeptide, which folds into a specific three-dimensional shape to become a functional protein.

7. **Conclusion**:
- Therefore, we conclude that proteins are polymers made up of amino acids.

### Final Answer:
**Protein is a polymer of amino acids.**

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