RNA polymerase, discovered by Ochoa (1953) is a holoenzyme and has how many poly-peptide chains ?

Options

A. 5
B. 2
C. 1
D. 4

Answer

To solve the question regarding the number of polypeptide chains in RNA polymerase, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding RNA Polymerase**:
- RNA polymerase is an enzyme responsible for synthesizing RNA from a DNA template. It plays a crucial role in the process of transcription.

2. **Identifying the Discovery**:
- The question mentions that RNA polymerase was discovered by Ochoa in 1953. This historical context is important but does not directly affect the answer to the question.

3. **Defining Holoenzyme**:
- A holoenzyme is a complete enzyme that consists of an apoenzyme (the protein part) and any necessary cofactors. In the case of RNA polymerase, it is referred to as a holoenzyme because it has multiple subunits.

4. **Counting the Polypeptide Chains**:
- RNA polymerase is composed of multiple polypeptide chains. Specifically, it consists of:
- 2 alpha chains
- 1 beta chain
- 1 beta' chain
- 1 sigma chain
- When we add these together, we find that RNA polymerase has a total of 5 polypeptide chains.

5. **Selecting the Correct Answer**:
- Given the options (5, 2, 1, 4), the correct answer is 5.

### Final Answer:
RNA polymerase has **5 polypeptide chains**.

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