Which of the following organelles is least closely associated with the endomembrane system?

Options

A. Plasma membrane
B. Golgi apparatus
C. Chloroplast
D. Nuclear envelope

Explanation

To determine which organelle is least closely associated with the endomembrane system, we need to understand what the endomembrane system is and which organelles are part of it.

### Step-by-Step Solution:

1. **Define the Endomembrane System**:
The endomembrane system is a network of membranes within the cell that includes the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, and the plasma membrane. These organelles are interconnected and work together in the synthesis, modification, packaging, and transport of proteins and lipids.

**Hint**: Remember that the endomembrane system is primarily involved in the processing and transport of biomolecules.

2. **Identify the Organelles in the Endomembrane System**:
The key organelles that are part of the endomembrane system include:
- Nuclear envelope
- Endoplasmic reticulum (ER)
- Golgi apparatus
- Lysosomes
- Plasma membrane

**Hint**: List out the organelles that are known to be part of the endomembrane system.

3. **Consider Other Organelles**:
Now, we need to consider organelles that are not part of the endomembrane system. Two primary organelles that are not included are:
- Mitochondria
- Chloroplasts

**Hint**: Think about which organelles have their own membranes and are involved in energy production or photosynthesis rather than transport and processing.

4. **Determine the Least Closely Associated Organelle**:
Between mitochondria and chloroplasts, both are not part of the endomembrane system. However, chloroplasts are the least closely associated with the endomembrane system because they are involved in photosynthesis and have a different evolutionary origin compared to the other organelles in the endomembrane system.

**Hint**: Consider the functions of chloroplasts and how they differ from the functions of the organelles in the endomembrane system.

### Final Answer:
The organelle that is least closely associated with the endomembrane system is **chloroplast**.