Protein synthesis occurs in cell in

Options

A. cytoplasm only
B. cytoplasm, mitochondria and chloroplast
C. ribosome attached on nuclear envelope
D. nucleolus and cytoplasm both

Answer

**Step-by-Step Solution:**

1. **Understanding Protein Synthesis**: Protein synthesis is the process by which cells create proteins. This process involves several cellular components, primarily ribosomes, which are the sites of protein synthesis.

2. **Identifying Locations of Protein Synthesis**:
- **Cytoplasm**: The cytoplasm contains ribosomes, which are essential for protein synthesis. Ribosomes can be free-floating or attached to the endoplasmic reticulum.
- **Mitochondria**: Mitochondria have their own ribosomes and are involved in synthesizing some proteins that are crucial for their function.
- **Chloroplasts**: In plant cells, chloroplasts also contain ribosomes and are involved in synthesizing proteins necessary for photosynthesis.

3. **Evaluating the Options**:
- **Option 1**: "Cytoplasm only" - This is incorrect because protein synthesis does not occur solely in the cytoplasm; it also occurs in mitochondria and chloroplasts.
- **Option 2**: "Cytoplasm, mitochondria, and chloroplasts" - This is correct as all these locations contain ribosomes and are involved in protein synthesis.
- **Option 3**: "Ribosome attached on nuclear envelope" - This is incorrect because the nuclear envelope does not have ribosomes that are involved in protein synthesis.
- **Option 4**: "Nucleolus and Cytoplasmic Brain" - This is incorrect as the nucleolus is involved in the synthesis of ribosomal RNA (rRNA) but not directly in protein synthesis.

4. **Conclusion**: The correct answer is **Option 2: Cytoplasm, mitochondria, and chloroplasts** because these are the locations where protein synthesis occurs due to the presence of ribosomes.