Final answer:
Sigma factor is involved in the initiation stage of bacterial transcription, where it recognizes the promoter region, allowing RNA polymerase to bind and initiate RNA synthesis. It is not involved in mRNA formation or the termination of replication. Thus, the option b is the correct answer.
Step-by-step explanation:
The correct answer regarding sigma factor is that it recognizes the promoter region. Sigma factor is an essential component of bacterial transcription and is involved in the initiation stage. It associates with RNA polymerase to form a holoenzyme, allowing the polymerase to recognize and bind to specific promoter sequences of DNA. Upon binding, the sigma factor helps to create an open complex by unwinding a short stretch of the DNA, facilitating the initiation of RNA synthesis.
The role of sigma factor is critical in the regulation of gene expression, as different sigma factors recognize different sets of promoters, thereby controlling the transcription of different sets of genes. It does not form mRNA, nor is it involved in the termination of replication or directly forming an open complex.
To further clarify, during bacterial transcription, specifically in E. coli, the sigma factor-associated RNA polymerase identifies and binds to the promoter region. This is reflected in the general process where transcription factors bind to the promoter region, creating the initiation complex necessary for transcription to begin. In this case, the sigma factor is part of the bacterial RNA polymerase initiation complex. The transcription initiation complex is a collection of proteins that prepare the DNA for transcription by RNA polymerase.