In eukaryotes, RNA polymerase II transcribes

Options

A. the precursor of tRNA
B. the precursor of mRNA
C. the precursor of snRNA
D. the precursor of rRNA

Answer

To solve the question, "In eukaryotes, RNA polymerase II transcribes," we need to identify what RNA polymerase II specifically transcribes among the given options.

### Step-by-Step Solution:

1. **Understand the Role of RNA Polymerases**: In eukaryotic cells, there are three main types of RNA polymerases, each responsible for transcribing different types of RNA.

2. **Identify RNA Polymerase Functions**:
- **RNA Polymerase I**: This enzyme primarily transcribes ribosomal RNA (rRNA), except for 5S rRNA.
- **RNA Polymerase II**: This enzyme is responsible for transcribing messenger RNA (mRNA) precursors, which are also known as heterogeneous nuclear RNA (hnRNA).
- **RNA Polymerase III**: This enzyme transcribes transfer RNA (tRNA), 5S rRNA, and small nuclear RNA (snRNA).

3. **Analyze the Options**: The question provides four options:
- Precursor of tRNA
- Precursor of mRNA
- Precursor of snRNA
- Precursor of rRNA

4. **Select the Correct Answer**: Since RNA polymerase II is specifically responsible for transcribing the precursor of mRNA, the correct answer is the "precursor of mRNA."

### Final Answer:
In eukaryotes, RNA polymerase II transcribes the precursor of mRNA.

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