Interconnected flattened sacs of endoplasmic reticulum are called

Options

A. Cisternae
B. Ribosomes
C. Tubules
D. Stroma

Answer

To answer the question "Interconnected flattened sacs of endoplasmic reticulum are called," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Endoplasmic Reticulum (ER)**:
- The endoplasmic reticulum is a membrane-bound organelle found in eukaryotic cells. It consists of a network of membranes that form interconnected sacs and tubules.

2. **Identify the Types of Endoplasmic Reticulum**:
- There are two main types of endoplasmic reticulum:
- **Rough Endoplasmic Reticulum (RER)**: Studded with ribosomes, involved in protein synthesis.
- **Smooth Endoplasmic Reticulum (SER)**: Lacks ribosomes, involved in lipid synthesis and detoxification processes.

3. **Focus on the Structure**:
- The interconnected flattened sacs of the endoplasmic reticulum are specifically referred to as **cisternae**. This term describes the flattened membrane-bound compartments that make up the ER.

4. **Consider Other Options**:
- It is important to differentiate between other possible terms:
- **Ribosomes**: Non-membranous structures involved in protein synthesis, not related to the structure of the ER.
- **Tubules**: Can be part of the ER structure but refer to tubular forms, not flattened sacs.
- **Stroma**: Refers to the fluid matrix in chloroplasts, not related to the ER.

5. **Conclusion**:
- Based on the above understanding, the correct answer to the question is that the interconnected flattened sacs of endoplasmic reticulum are called **cisternae**.

### Final Answer:
The interconnected flattened sacs of endoplasmic reticulum are called **cisternae**.