What is more abundant in R.E.R

Options

A. Cisternae
B. Vesicles
C. Tubules
D. Both A and B

Answer

### Step-by-Step Solution:

1. **Understanding the Structure of Endoplasmic Reticulum (ER)**:
- The endoplasmic reticulum (ER) is a network of membrane-bound structures within eukaryotic cells. It consists of flattened membranes and closed sacs.

2. **Identifying the Types of Endoplasmic Reticulum**:
- The ER is divided into two types:
- **Rough Endoplasmic Reticulum (RER)**: Studded with ribosomes, giving it a "rough" appearance.
- **Smooth Endoplasmic Reticulum (SER)**: Lacks ribosomes and appears smooth.

3. **Focusing on Rough Endoplasmic Reticulum (RER)**:
- The RER is primarily involved in the synthesis of proteins due to the presence of ribosomes on its surface.

4. **Components of RER**:
- The RER is made up of various structures including:
- **Cisternae**: Flattened membrane-bound sacs.
- **Vesicles**: Small membrane-bound sacs that transport materials.
- **Tubules**: Tube-like structures that connect different parts of the ER.

5. **Determining the Most Abundant Structure in RER**:
- Among the components mentioned, the **cisternae** are more abundant in the rough endoplasmic reticulum compared to vesicles and tubules.

6. **Conclusion**:
- Therefore, the answer to the question "What is more abundant in R.E.R?" is **Cisternae**.

### Final Answer:
- **Cisternae** are more abundant in Rough Endoplasmic Reticulum (RER).

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