Smallest cell organelle which is called protein factory is

Options

A. ribosome
B. Lysosome
C. vacuoles
D. endoplasmic reticulum

Answer

**Step-by-Step Solution:**

1. **Identify the Options**: The question provides four options: ribosome, lysosome, vacuoles, and endoplasmic reticulum.

2. **Understand Ribosomes**: Ribosomes are granular structures first observed by George Palladay. They are composed of two subunits made of RNA and proteins.

3. **Distinguish Ribosome Types**: Ribosomes are present in both prokaryotic and eukaryotic cells. Prokaryotes have 70S ribosomes, while eukaryotes have 80S ribosomes.

4. **Function of Ribosomes**: The primary function of ribosomes is the synthesis of proteins, which is why they are referred to as the "protein factory" of the cell.

5. **Evaluate Other Options**:
- **Lysosomes**: These are membrane-bound organelles containing hydrolytic enzymes, but they are not involved in protein synthesis.
- **Vacuoles**: These are storage organelles that hold water, sap, and waste materials, not proteins.
- **Endoplasmic Reticulum (ER)**: While the rough ER is involved in protein synthesis, it is not the smallest organelle and is not solely responsible for protein synthesis like ribosomes are.

6. **Conclusion**: Based on the above information, the smallest cell organelle known as the protein factory is the ribosome.

**Final Answer**: Ribosome

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