Which of the following is the site of protein synthesis?

Options

A. DNA
B. nucleolus
C. ribosomes
D. chloroplasts

Answer

To determine the site of protein synthesis from the given options, we can analyze each option step by step:

### Step 1: Understanding the Options
The options provided are:
1. DNA
2. Nucleolus
3. Ribosomes
4. Chloroplast

### Step 2: Analyzing Each Option
- **DNA**: DNA (deoxyribonucleic acid) is the genetic material that contains the instructions for building proteins, but it is not directly involved in the synthesis of proteins. It serves as a template for transcription, which is the first step in protein synthesis.

- **Nucleolus**: The nucleolus is a structure within the nucleus of eukaryotic cells where ribosomal RNA (rRNA) is synthesized and ribosome subunits are assembled. However, it is not the site where proteins are synthesized.

- **Ribosomes**: Ribosomes are the cellular structures where protein synthesis occurs. They translate messenger RNA (mRNA) into polypeptide chains, which then fold into functional proteins. Ribosomes can be found free in the cytoplasm or attached to the rough endoplasmic reticulum (RER).

- **Chloroplast**: Chloroplasts are organelles found in plant cells that conduct photosynthesis. While they contain their own ribosomes and can synthesize some proteins, they are not the primary site of protein synthesis in the cell.

### Step 3: Conclusion
Based on the analysis, the correct answer is **Ribosomes**. They are the primary site of protein synthesis in the cell.

### Final Answer
The site of protein synthesis is **Ribosomes**.

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