Ribosomes are classified according to their

Options

A. size
B. weight
C. volume
D. sedimentation rate

Answer

To solve the question regarding how ribosomes are classified, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ribosomes**: Ribosomes are cellular structures responsible for protein synthesis. They can be found in both prokaryotic and eukaryotic cells.

2. **Classification Basis**: Ribosomes are classified based on their sedimentation rate, which is measured in Svedberg units (S). This sedimentation rate reflects their size and density.

3. **Types of Ribosomes**: There are two main types of ribosomes:
- **70S Ribosomes**: Found in prokaryotes (like bacteria) and in the mitochondria and chloroplasts of eukaryotic cells.
- **80S Ribosomes**: Found in the cytoplasm of eukaryotic cells.

4. **Sedimentation Rate**: The classification is determined by the sedimentation values:
- **70S** ribosomes sediment at a rate of 70S.
- **80S** ribosomes sediment at a rate of 80S.
This difference in sedimentation rates is due to their size and weight.

5. **Isolation and Analysis**: Ribosomes can be isolated using techniques like magnesium precipitation and density gradient ultracentrifugation. During ultracentrifugation, ribosomes settle into distinct bands based on their sedimentation rates.

6. **Sensitivity to Antibiotics**: The two types of ribosomes also differ in their sensitivity to certain antibiotics:
- **70S ribosomes** are sensitive to Chloramphenicol.
- **80S ribosomes** are sensitive to Cyclohexamide.

7. **Conclusion**: Therefore, ribosomes are classified according to their sedimentation rate, which is the correct answer to the question.

### Final Answer:
Ribosomes are classified according to their sedimentation rate.

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