How does a cell rid itself of defective or malfunctioning organelles ?

Options

A. They are engulfed by plastids and stored until export from cell is possible.
B. Defective parts accumulate until the cell itself dies.
C. They are exported by exocytosis.
D. Lysosomes assist in the removal of defective organelles by digesting them.

Answer

### Step-by-Step Solution:

1. **Understanding the Role of Lysosomes**:
- Lysosomes are specialized organelles within the cell that are often referred to as "suicide bags" due to their ability to break down and digest various cellular components.

2. **Function of Lysosomes**:
- They contain enzymes known as hydrolases, which are crucial for the breakdown of biomolecules. These enzymes help in digesting larger molecules into smaller, manageable units.

3. **Process of Digestion**:
- When a cell identifies defective or malfunctioning organelles, lysosomes come into action. They engulf these defective organelles and use hydrolase enzymes to digest them.

4. **Autolytic Nature**:
- The process carried out by lysosomes is known as autolysis, where they effectively remove damaged or non-functional components from the cell, ensuring the cell remains healthy.

5. **Final Removal**:
- After digestion, the waste materials are either reused by the cell or expelled from the cell, thus maintaining cellular health and function.

6. **Conclusion**:
- Therefore, the correct mechanism by which a cell rids itself of defective organelles is through the action of lysosomes, which digest these organelles and facilitate their removal.