A geneticist finds that a strain of bacteria to produces a non-functional sigma factor. Which among the following steps in transcription would most likely be first affected? A. Assembly of RNAP onto the DNA strand

B. Identification and binding of RNAP on to the promoter sequence

C. Conversion of open initiation complex to closed initiation complex

D. Synthesis of RNA after the formation of open initiation complex

Answer

D

The transcription factors and RNA polymerase form a complex called the transcription initiation complex. This complex initiates transcription, and the RNA polymerase begins mRNA synthesis by matching complementary bases to the original DNA strand.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.