Which of the following is seen only in prokaryotic cells?

Options

A. Dictyosome
B. Ribosome
C. Mesosome
D. Endoplasmic reticulum

Answer

To solve the question "Which of the following is seen only in prokaryotic cells?" we will analyze each option provided:

1. **Dictosome**:
- A dictosome is a stack of Golgi apparatus in eukaryotic cells. It is not found in prokaryotic cells. Therefore, this option is not correct.

2. **Ribosome**:
- Ribosomes are present in both prokaryotic and eukaryotic cells. While the structure and size of ribosomes differ between these two types of cells, they are not exclusive to prokaryotes. Hence, this option is also not correct.

3. **Mesosome**:
- Mesosomes are specialized structures found in prokaryotic cells, specifically in bacteria. They are invaginations of the plasma membrane and are involved in various functions such as DNA replication and respiration. Mesosomes are not found in eukaryotic cells. Therefore, this option is correct.

4. **Endoplasmic Reticulum (ER)**:
- The endoplasmic reticulum is a membrane-bound organelle found only in eukaryotic cells. It is involved in protein and lipid synthesis. Thus, this option is not correct.

After analyzing all the options, we conclude that the correct answer is **C. Mesosome**, as it is the only structure that is exclusively found in prokaryotic cells.