Which parts of a cell contain ribosomes ?
I. Chloroplast
II. Mitochondrion
III. Nucleus
IV. Cytoplasm

Options

A. I,II , III and IV
B. I,II and III only
C. I,II and IV only
D. III and IV only

Answer

To determine which parts of a cell contain ribosomes, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Chloroplast**:
- Chloroplasts are organelles found in plant cells that are primarily responsible for photosynthesis.
- They also contain ribosomes, specifically the 70S type, which are involved in protein synthesis.
- **Conclusion**: Chloroplasts contain ribosomes.

2. **Mitochondrion**:
- Mitochondria are known as the powerhouse of the cell, responsible for producing ATP through cellular respiration.
- Similar to chloroplasts, mitochondria also contain 70S ribosomes, referred to as mitoribosomes, which are involved in synthesizing proteins necessary for mitochondrial function.
- **Conclusion**: Mitochondria contain ribosomes.

3. **Nucleus**:
- The nucleus is the control center of the cell, housing the genetic material (DNA).
- While ribosomes are not fully formed within the nucleus, the nucleolus (a structure within the nucleus) is where ribosomal RNA (rRNA) is synthesized and combined with proteins to form the subunits of ribosomes.
- Therefore, while ribosomes are not present as functional units in the nucleus, they are produced there.
- **Conclusion**: The nucleus is involved in ribosome production.

4. **Cytoplasm**:
- The cytoplasm is the gel-like substance within the cell membrane where various organelles are located.
- Free ribosomes are present in the cytoplasm, which synthesize proteins that function within the cytosol.
- **Conclusion**: The cytoplasm contains ribosomes.

### Final Answer:
All four parts of the cell mentioned in the question—chloroplast, mitochondrion, nucleus, and cytoplasm—contain ribosomes in some form. Therefore, the correct answer is that all options (I, II, III, and IV) are correct.

---