Question

In E.coli, rho factor is required for:
(A) Initiation of transcription at specific site
(B) Initiation of transcription at many sites
(C) Termination of transcription at specific site
(D) Termination of transcription at many sites

Answer 1

Hint: Replication, transcription and translation are the processes under central dogma. Transcription requires Rho factors for both initiation and termination of the process. Sigma factor is required for initiation of transcription, RNA polymerase for elongation and rho factor is required for termination of transcription.
Step by step solution:
Replication is a process in which new DNA is synthesized from already existing DNA strands, (semiconservative method of DNA replication is carried out in humans), replication occurs in the S phase of cell division.
Transcription is a process in which mRNA is synthesized from the DNA strand, this process occurs in the nucleus itself, and it requires certain initiation, elongation, and termination factors.
Now, coming on to the process of transcription, we have already discussed that three factors that are initiation factor, elongation factor and termination factor are required to carry out transcription. There are three major types of RNAs that is mRNA, tRNA, and rRNA. All these three RNA are required to synthesize protein. The transcription unit has three regions that are a promoter, structural gene and terminator. RNA polymerase is required for the process of elongation.
The first process of transcription is initiation, for the process to initiate RNA polymerase has to bind with the promoter region. To aid this process sigma factor is required which is also known as the initiation factor. The second step that is elongation is carried out by RNA polymerase alone. The third step is termination, in this step RNA polymerase is needed to be removed from the transcription unit, to aid this step a rho factor or termination factor is required.
therefore, from the above information it is clear that option (C) is correct.
Note: The sigma factor and rho factor are required only in case of prokaryotes such as E.coli (bacteria). In prokaryotes only a single RNA polymerase is required but in eukaryotes there are additional complexities as well.