Which organelle is not a part of the endomembrane system ?

Options

A. ER
B. Golgi complex
C. Lysosomes
D. Mitochondria

Explanation

To determine which organelle is not a part of the endomembrane system, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Endomembrane System**: The endomembrane system consists of various organelles that communicate and work together within the cell. This includes the endoplasmic reticulum (ER), Golgi apparatus, lysosomes, and vacuoles.

2. **Identify the Organelles**: We need to identify the organelles mentioned in the question:
- Endoplasmic Reticulum (ER)
- Golgi Complex
- Lysosomes
- Mitochondria

3. **Analyze Each Organelle**:
- **Endoplasmic Reticulum (ER)**: This organelle is part of the endomembrane system. It is involved in the synthesis and transport of proteins and lipids.
- **Golgi Complex**: This organelle is also part of the endomembrane system. It modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
- **Lysosomes**: These are part of the endomembrane system as well. They contain hydrolytic enzymes for digestion and waste processing within the cell.
- **Mitochondria**: This organelle is known as the powerhouse of the cell, responsible for energy production through cellular respiration. However, it does not participate in the endomembrane system's transport and communication processes.

4. **Conclusion**: Since the mitochondria do not coordinate with the endomembrane system and are functionally distinct, they are not considered part of this system.

### Final Answer:
The organelle that is not a part of the endomembrane system is **Mitochondria**.

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