Question

question 2
put the following events of bacterial transcription in chronological order.

1. sigma binds to the promoter region.
2. the double helix of dna is unwound, breaking hydrogen bonds between complementary strands.
3. sigma binds to rna polymerase.
4. sigma is released.
5. transcription begins.

a 2, 3, 4, 5, 1
b 2, 3, 1, 4, 5
c 3, 1, 2, 5, 4
d 3, 2, 1, 4, 5

Explanation:

• First, sigma binds to RNA polymerase (3). This is the initial step to form the RNA polymerase - sigma factor complex.
• Then, the complex (sigma + RNA polymerase) binds to the promoter region (1). The promoter is a specific DNA sequence that signals the start of transcription.
• After binding to the promoter, the double helix of DNA is unwound (2). This exposes the template strand for transcription.
• Once transcription begins (5), the sigma factor is no longer needed and is released (4).

Answer:

C. 3, 1, 2, 5, 4