Which of the following are correct for the sequence of steps in transcription

Options

A. (a) Elongation, (b) Termination, (c) Initiation
B. (a) Initiation, (b) Termination, (c) Elongation
C. (a) Initiation, (b) Elongation, (c) Termination
D. (a) Termination, (b) Elongation, (c) Initiation

Answer

To solve the question regarding the correct sequence of steps in transcription, we can break it down into clear steps:

### Step-by-Step Solution:

1. **Initiation**:
- The first step in transcription is initiation. This process begins when the enzyme RNA polymerase binds to a specific region of the DNA called the promoter.
- In prokaryotes, RNA polymerase requires a sigma factor to initiate transcription. The sigma factor helps the RNA polymerase recognize and bind to the promoter region of the DNA.

2. **Elongation**:
- After initiation, the next step is elongation. During this phase, RNA polymerase moves along the DNA template strand, synthesizing a complementary strand of mRNA.
- Ribonucleotides are added one by one to the growing mRNA strand according to the base-pairing rules (A pairs with U, and C pairs with G).

3. **Termination**:
- The final step in transcription is termination. This occurs when RNA polymerase reaches a specific sequence of nucleotides that signals the end of transcription.
- In prokaryotes, this can involve the Rho factor, which helps to disassociate the RNA polymerase from the DNA, leading to the release of the newly synthesized mRNA strand.

### Conclusion:
The correct sequence of steps in transcription is:
1. Initiation
2. Elongation
3. Termination

Thus, the correct option for the question is option number three.

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