Which of the following subcellular structures cannot be isolated ?

Options

A. nuclei
B. lysosomes
C. Mitochondria
D. endoplasmic reticulum

Answer

To solve the question "Which of the following subcellular structures cannot be isolated?" we will analyze each option provided and determine their isolation feasibility.

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify which subcellular structure cannot be isolated from the options given: nuclei, lysosomes, mitochondria, and endoplasmic reticulum.

2. **Analyze Each Option**:
- **Nuclei**:
- The nuclei can be isolated easily through the lysis of the cell. This process involves breaking down the cell membrane to release the nucleus.
- **Conclusion**: Nuclei can be isolated.

- **Lysosomes**:
- Lysosomes can be isolated using differential centrifugation, which separates cellular components based on their density.
- **Conclusion**: Lysosomes can be isolated.

- **Mitochondria**:
- Mitochondria, known as the powerhouse of the cell, can also be isolated through differential centrifugation, similar to lysosomes.
- **Conclusion**: Mitochondria can be isolated.

- **Endoplasmic Reticulum (ER)**:
- The endoplasmic reticulum is a complex network of membranes surrounding the nucleus. Due to its structure and the way it is integrated into the cell, isolating the endoplasmic reticulum is considerably more challenging.
- **Conclusion**: Endoplasmic reticulum cannot be easily isolated.

3. **Final Answer**: Based on the analysis, the subcellular structure that cannot be isolated is the **endoplasmic reticulum**.