Factory of ribosome in a cell is :–

Options

A. Endoplasmic reticulum
B. Nucleolus
C. Mitochondria
D. Golgi body

Answer

To solve the question "Factory of ribosome in a cell is:", we will analyze the options provided and identify the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding Ribosome Function**:
- Ribosomes are essential cellular structures responsible for protein synthesis. They translate messenger RNA (mRNA) into polypeptide chains, which then fold into functional proteins.

2. **Identifying the Options**:
- The question likely presents several options, including:
- A) Endoplasmic Reticulum
- B) Nucleolus
- C) Mitochondria
- D) Golgi Body

3. **Evaluating Each Option**:
- **Option A: Endoplasmic Reticulum (ER)**:
- The ER is involved in protein and lipid synthesis. The rough ER has ribosomes on its surface, which are involved in protein synthesis, but it is not the site where ribosomes are made.
- **Option B: Nucleolus**:
- The nucleolus is a dense region within the nucleus where ribosomal RNA (rRNA) is synthesized and combined with proteins to form ribosomal subunits. This makes the nucleolus the primary site for ribosome production, hence it is often referred to as the "factory of ribosomes."
- **Option C: Mitochondria**:
- Mitochondria are known as the powerhouse of the cell, primarily involved in energy production through cellular respiration. They do not play a role in ribosome production.
- **Option D: Golgi Body**:
- The Golgi apparatus is involved in the sorting, modification, and packaging of proteins for secretion or delivery to other organelles. It does not synthesize ribosomes.

4. **Conclusion**:
- After evaluating all the options, the correct answer is **Option B: Nucleolus**, as it is the site where ribosomes are synthesized.

### Final Answer:
The factory of ribosome in a cell is the **Nucleolus**.