The set of the organelles/structure that are absent in plant cell are

Options

A. 70S - Ribosome + dictyosomes
B. 80S - Ribosome + dictyosomes
C. Vacuole + chloroplast
D. Centriole + mesosomes

Answer

To determine the set of organelles/structures that are absent in plant cells, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Ribosomes**:
- **70S Ribosomes**: These are typically found in prokaryotic cells (like bacteria) and are not specific to plant cells.
- **80S Ribosomes**: These are found in eukaryotic cells, including plant cells. Therefore, both types of ribosomes are not absent in plant cells.
- **Conclusion**: Ribosomes (both 70S and 80S) are present in plant cells.

2. **Analyzing Dictisome**:
- A dictisome is a part of the Golgi apparatus, which is involved in modifying, sorting, and packaging proteins for secretion or use within the cell.
- The Golgi apparatus is present in plant cells.
- **Conclusion**: Dictisome is present in plant cells.

3. **Examining Vacuoles**:
- Vacuoles are large membrane-bound structures that store substances such as water, nutrients, and waste products.
- In plant cells, vacuoles can occupy a significant portion of the cell's volume, often up to 90%.
- **Conclusion**: Vacuoles are present in plant cells.

4. **Looking at Chloroplasts**:
- Chloroplasts are double membrane-bound organelles responsible for photosynthesis in plants.
- They are essential for plant cells as they convert light energy into chemical energy.
- **Conclusion**: Chloroplasts are present in plant cells.

5. **Identifying Centrioles**:
- Centrioles are cylindrical structures involved in cell division and are typically found in animal cells.
- They play a crucial role in the formation of the spindle apparatus during mitosis.
- **Conclusion**: Centrioles are absent in plant cells.

6. **Understanding Mesosomes**:
- Mesosomes are structures formed by the infolding of the plasma membrane in prokaryotic cells, particularly bacteria.
- They are not found in eukaryotic cells, including plant cells.
- **Conclusion**: Mesosomes are absent in plant cells.

### Final Conclusion:
Based on the analysis, the organelles/structures that are absent in plant cells are **Centrioles and Mesosomes**. Therefore, the correct answer is the fourth option: **Centriole plus Mesosome**.

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