Which cell organelle is absent in the leaves of onion ?

Options

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

Answer

To solve the question "Which cell organelle is absent in the leaves of onion?", we can follow these steps:

### Step 1: Understand the Question
The question is asking for a specific cell organelle that is not present in the leaves of onion. This requires knowledge of the structure and composition of onion leaves.

**Hint:** Think about the common organelles found in plant cells and which ones might be missing in specialized cells like those in onion leaves.

### Step 2: Analyze the Options
We have four options to consider:
1. Nucleus
2. Cell wall
3. Centriole
4. Endoplasmic reticulum

**Hint:** Recall the functions and typical presence of these organelles in plant cells.

### Step 3: Evaluate Each Option
- **Nucleus:** This organelle is essential for all cells, including those in onion leaves, as it contains genetic material and controls gene expression. Therefore, it is present in onion leaves.

- **Cell wall:** The cell wall is a defining feature of plant cells, providing structure and protection. It is present in onion leaves.

- **Centriole:** Centrioles are involved in cell division and are typically found in animal cells. They are generally absent in the cells of higher plants, including onion leaves.

- **Endoplasmic reticulum:** This organelle is involved in protein synthesis and is also present in plant cells, including those in onion leaves.

**Hint:** Identify which of the organelles is typically not found in plant cells, especially in the context of onion leaves.

### Step 4: Conclusion
Based on the analysis, the correct answer is that the **Centriole** is the organelle that is absent in the leaves of onion.

**Final Answer:** Centriole