ER has a structure similar to

Options

A. cell wall
B. cell membrane
C. tonoplast
D. mitochondria

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the structure that is similar to the Endoplasmic Reticulum (ER). We need to analyze the given options: cell wall, cell membrane, tonoplast, and mitochondria.

2. **Analyzing the First Option - Cell Wall**:
- The cell wall is a rigid structure that provides support and protection to the cell. It is located outside the cell membrane.
- The ER is located inside the cell, so it does not have a similar structure to the cell wall.
- **Conclusion**: This option is incorrect.

3. **Analyzing the Second Option - Cell Membrane**:
- The cell membrane is a flexible structure that surrounds the cell, composed of a lipid bilayer with embedded proteins.
- The rough endoplasmic reticulum (RER) has ribosomes on its surface, similar to how proteins are embedded in the cell membrane.
- **Conclusion**: This option is correct.

4. **Analyzing the Third Option - Tonoplast**:
- The tonoplast is a membrane that surrounds the vacuole in plant cells. It is specific to plant cells and does not relate to the structure of the ER.
- **Conclusion**: This option is incorrect.

5. **Analyzing the Fourth Option - Mitochondria**:
- Mitochondria are organelles with a distinct rod-like structure and are responsible for energy production in the cell.
- They are separate structures and do not share a similar structure with the ER.
- **Conclusion**: This option is incorrect.

6. **Final Answer**: Based on the analysis, the structure that is similar to the Endoplasmic Reticulum is the **cell membrane**.