Select the incorrect statement about nucleolus .

Options

A. It is membrane-less cell organelle.
B. It is active site for m-RNA synthesis .
C. These may be more than 1 in cells which are involved in active protein synthesis .
D. Found in nucleus .

Answer

To solve the question regarding the incorrect statement about the nucleolus, we will analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Identify the Characteristics of Nucleolus:**
- The nucleolus is a membrane-less organelle found within the nucleus of eukaryotic cells.
- It is primarily involved in the synthesis of ribosomal RNA (rRNA) and the assembly of ribosomes.
- There can be one or more nucleoli present in a cell, depending on the cell's activity and type.

2. **Evaluate Each Statement:**
- **Statement 1:** "It is a membrane-less cell organelle."
- This statement is **correct**. The nucleolus does not have a surrounding membrane.

- **Statement 2:** "It is an active site for mRNA synthesis."
- This statement is **incorrect**. The nucleolus is primarily involved in rRNA synthesis, not mRNA synthesis. mRNA synthesis occurs in the nucleoplasm, where the DNA is transcribed.

- **Statement 3:** "There can be one or more than one nucleolus in the cell."
- This statement is **correct**. Depending on the cell type and its activity, there can be multiple nucleoli.

- **Statement 4:** "They are responsible for active protein synthesis."
- This statement is **correct**. While the nucleolus itself does not synthesize proteins, it is essential for producing rRNA, which is a component of ribosomes, the sites of protein synthesis.

3. **Conclusion:**
- The incorrect statement about the nucleolus is **Statement 2**, which claims that it is an active site for mRNA synthesis.

### Final Answer:
The incorrect statement about the nucleolus is: **"It is an active site for mRNA synthesis."**