Question

Put the following events of 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. 3, 2, 1, 4, 5B. 2, 3, 4, 5, 1C. 2, 3, 1, 4, 5D. 3, 1, 2, 5, 4

Answer 1

Answer:D

Step-by-step explanation:

First, sigma bind to RNA polymerase. The RNAP enzyme contains two alpha, two beta, one omega subunits, two zinc molecules and one sigma factor. The sigma factor helps the RNAP to recognize the promoter site and increases the enzyme affinity to the promoter site

Secondly, the RNAP binds to the promoter site on the DNA strand with the help of the sigma factor. The promoter site are specific area on the DNA that act as starting signals for initiation process.

Thirdly, the DNA helix partially unwind so the enzyme can ''read'' the bases in one of the DNA strands.

Transcription begins as the first nucleotide of the mRNA attaches to the initiation site. It will be complementary to the base present in the DNA at the site

Lastly, after the nucleotide in the promoter region are transcribed and polymerised. RNAP undergo conformational change and move away from the promoter region

Then sigma factor is released and gene elongation process begins.