RNA synthesis is controlled by-

Options

A. (a) Rho-factor
B. (b) Sigma factor
C. (c) Endo-nuclease
D. (d) RNA-polymerase

Answer

**Step-by-Step Solution:**

1. **Understanding RNA Synthesis**: RNA synthesis is a biological process known as transcription, where a DNA strand serves as a template to synthesize RNA.

2. **Identifying the Role of DNA**: In transcription, the DNA provides the necessary information for the synthesis of RNA. The DNA strand has two types: the coding strand and the template strand. The RNA synthesized is complementary to the template strand.

3. **Recognizing the Enzyme Involved**: The key enzyme that facilitates RNA synthesis is RNA polymerase. Specifically, it is referred to as DNA-dependent RNA polymerase because it requires a DNA template to synthesize RNA.

4. **Evaluating the Options**: The options provided are:
- A) Rho factor
- B) Sigma factor
- C) Endonuclease
- D) RNA polymerase

5. **Analyzing Each Option**:
- **Rho factor**: This is involved in the termination of transcription in prokaryotes but does not control the synthesis itself.
- **Sigma factor**: This assists RNA polymerase in initiating transcription in prokaryotes but is not the main enzyme for RNA synthesis.
- **Endonuclease**: This enzyme cuts DNA at specific sites and does not play a role in RNA synthesis.
- **RNA polymerase**: This is the correct enzyme that directly controls RNA synthesis by using the DNA template.

6. **Conclusion**: The correct answer is **D) RNA polymerase**, as it is the primary enzyme responsible for the synthesis of RNA during transcription.

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