Transcription starts non-specifically in the absence of
(a) Sigma factor
(b) Rho factor
(c) Core enzyme
(d) DNA polymerase

Options

A. Sigma factor
B. Rho foctor
C. Core enzyme
D. DNA polymerase

Answer

To solve the question regarding what transcription starts non-specifically in the absence of, we can follow these steps:

### Step 1: Understand the Process of Transcription
Transcription is the process by which RNA is synthesized from a DNA template. It involves several key components, including RNA polymerase and various factors that help initiate and regulate the process.

### Step 2: Identify the Role of the Sigma Factor
The sigma factor is a protein that is essential for the initiation of transcription in bacteria. It helps RNA polymerase recognize and bind to specific promoter regions on the DNA. This specificity is crucial for ensuring that transcription starts at the correct location.

### Step 3: Analyze the Options Given
- **(a) Sigma factor**: As discussed, this factor is crucial for the specific binding of RNA polymerase to the promoter.
- **(b) Rho factor**: This is involved in the termination of transcription, not initiation.
- **(c) Core enzyme**: This refers to the RNA polymerase without the sigma factor; it cannot initiate transcription on its own.
- **(d) DNA polymerase**: This enzyme is involved in DNA replication, not transcription.

### Step 4: Conclusion
In the absence of the sigma factor, RNA polymerase cannot bind specifically to the promoter region and will instead bind non-specifically to the DNA. Therefore, transcription will start non-specifically.

### Final Answer
The correct answer is **(a) Sigma factor**.

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