RER is rough as it contains the

Options

A. Ribosomes
B. Lysosomes
C. Mitochondria
D. Volutin granules

Explanation

To answer the question "RER is rough as it contains the", we need to analyze the options provided and understand the characteristics of the Rough Endoplasmic Reticulum (RER).

### Step-by-Step Solution:

1. **Understanding RER**: The Rough Endoplasmic Reticulum (RER) is a type of endoplasmic reticulum that is characterized by the presence of ribosomes on its cytoplasmic surface.

2. **Identifying the Options**:
- **Option 1: Ribosome** - Ribosomes are the cellular structures responsible for protein synthesis.
- **Option 2: Lysosome** - Lysosomes are organelles that contain enzymes for digestion.
- **Option 3: Mitochondria** - Mitochondria are the powerhouses of the cell, involved in energy production.
- **Option 4: Vaulting Granules** - Vaults are large ribonucleoprotein particles, but they are not directly related to the RER.

3. **Analyzing the RER's Structure**: The RER is termed "rough" because of the ribosomes that are attached to its surface. These ribosomes give it a rough appearance under a microscope.

4. **Function of RER**: The primary function of the RER is to synthesize proteins that are either secreted from the cell, incorporated into the cell's plasma membrane, or sent to an organelle.

5. **Conclusion**: Since the RER is characterized by the presence of ribosomes, the correct answer to the question is **Option 1: Ribosome**.

### Final Answer:
RER is rough as it contains ribosomes.

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