On the basis of rRNA genes, bacteria are divisible into

Options

A. Cyanobacteria and mycoplasma
B. Actinomycetes and Mycoplasma
C. Bacteria and Archaebacteria
D. Gram (+) and Gram (-).

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how bacteria can be classified based on rRNA genes. Specifically, it is looking for the correct classification scheme that divides bacteria into distinct groups.

2. **Identifying Key Concepts**: The classification of bacteria based on rRNA genes is primarily attributed to the work of Carl Woese. He utilized the sequences of 16S rRNA genes to classify organisms into three domains: Archaea, Bacteria, and Eukarya.

3. **Analyzing the Options**:
- Option 1: Cyanobacteria and Mycoplasma - These are specific types of bacteria but do not represent a broad classification based on rRNA.
- Option 2: Actinomycetes and Mycoplasma - Similar to the first option, these are specific groups and not a comprehensive classification.
- Option 3: Bacteria and Archaeobacteria - This option reflects the division made by Woese, as it includes the two main groups of prokaryotes.
- Option 4: Gram-positive and Gram-negative - This classification is based on cell wall structure and staining properties, not specifically on rRNA genes.

4. **Selecting the Correct Answer**: Based on the analysis, the correct classification of bacteria based on rRNA genes is represented in Option 3: Bacteria and Archaeobacteria.

5. **Conclusion**: Therefore, the answer to the question is that bacteria are divisible into Bacteria and Archaeobacteria based on rRNA genes.

**Final Answer**: Bacteria are divisible into Bacteria and Archaeobacteria based on rRNA genes (Option 3).

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