Which is mismatched?

Options

A. RNA Polymerase I - 18S rRNA synthesis
B. RNA Polymerase II - HnRNA synthesis
C. RNA Polymerase III - ScRNA synthesis
D. RNA Polymerase II - 5.8S rRNA synthesis

Answer

To determine which option is mismatched, we need to analyze the functions of the different RNA polymerases in eukaryotes and the types of RNA they transcribe.

### Step-by-Step Solution:

1. **Identify the Types of RNA Polymerases in Eukaryotes**:
- Eukaryotes have three main types of RNA polymerases:
- **RNA Polymerase I** (Pol I)
- **RNA Polymerase II** (Pol II)
- **RNA Polymerase III** (Pol III)

2. **List the RNA Transcribed by Each Polymerase**:
- **RNA Polymerase I**:
- Transcribes 18S rRNA
- Transcribes 5.8S rRNA
- Transcribes 28S rRNA
- **RNA Polymerase II**:
- Transcribes heteronuclear RNA (hnRNA), which is a precursor to mRNA
- Transcribes microRNA (miRNA)
- **RNA Polymerase III**:
- Transcribes tRNA
- Transcribes 5S rRNA
- Transcribes small nuclear RNA (snRNA) and small conditional RNA

3. **Evaluate Each Option**:
- **Option A**: RNA Polymerase I, 18S ribosomal RNA
- This is correct; RNA Polymerase I does transcribe 18S rRNA.
- **Option B**: RNA Polymerase II, heteronuclear RNA
- This is correct; RNA Polymerase II transcribes hnRNA.
- **Option C**: RNA Polymerase III, small conditional RNA
- This is correct; RNA Polymerase III transcribes small conditional RNA.
- **Option D**: RNA Polymerase II, 5.8S ribosomal RNA
- This is incorrect; RNA Polymerase I transcribes 5.8S rRNA, not RNA Polymerase II.

4. **Conclusion**:
- The mismatched option is **Option D: RNA Polymerase II, 5.8S ribosomal RNA**.

### Final Answer:
**Option D is mismatched.**

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