Which of the following structures is not found prokaryotic cell?

Options

A. Ribosome
B. Mesosome
C. Plasma membrane
D. Nuclear envelope

Answer

To determine which structure is not found in prokaryotic cells, we can analyze the options provided:

1. **Ribosome**:
- Ribosomes are essential for protein synthesis and are found in all living cells, including prokaryotic cells. Therefore, this option is incorrect.

2. **Mesosome**:
- Mesosomes are infoldings of the plasma membrane in prokaryotic cells, particularly in bacteria. They are involved in various functions, including respiration. Thus, this option is also incorrect.

3. **Plasma Membrane**:
- The plasma membrane is a fundamental structure present in all cells, including prokaryotic cells. It acts as a barrier and regulates the movement of substances in and out of the cell. Hence, this option is incorrect.

4. **Nuclear Envelope**:
- The nuclear envelope is a double membrane structure that surrounds the nucleus in eukaryotic cells. Prokaryotic cells, such as bacteria, do not have a well-defined nucleus or a nuclear envelope. Instead, their genetic material is located in the cytoplasm. Therefore, this option is correct.

**Final Answer**: The structure that is not found in prokaryotic cells is the **Nuclear Envelope**.