Which cell organelle is absent in the leaves of onion ?

Options

A. Nucleus
B. Cell wall
C. Centriole
D. Endoplasmic reticulum

Answer

To determine which cell organelle is absent in the leaves of onion, we can analyze the options provided: nucleus, cell wall, centriole, and endoplasmic reticulum.

### Step-by-Step Solution:

1. **Understanding Onion Leaves**: Onion leaves are primarily composed of epidermal cells. These cells are specialized for storage rather than photosynthesis, which is why they do not contain chloroplasts.

2. **Analyzing Each Organelle**:
- **Nucleus**: The nucleus is present in the epidermal cells of onion leaves. It is located at the periphery of the cytoplasm.
- **Cell Wall**: The cell wall is also present in onion leaves as it is a characteristic feature of plant cells.
- **Endoplasmic Reticulum**: The endoplasmic reticulum is present in the cells, as it plays a role in protein and lipid synthesis.
- **Centriole**: Centrioles are typically found in animal cells and are involved in cell division. In plant cells, including onion leaves, centrioles are generally absent.

3. **Conclusion**: After analyzing the presence of each organelle, we find that the only organelle that is absent in the leaves of onion is the centriole.

### Final Answer:
The cell organelle that is absent in the leaves of onion is **Centriole** (Option C).

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