Question

What will happen if the promoter sequence for a specific gene is removed so that it is no longer present, but the rest of the chromosome remains unchanged?

A.The corresponding pre-mRNA will not be made.

B.Transcription will occur.

C.A longer than normal pre-mRNA will be made.

D.A shorter than normal pre-mRNA will be made.

E.B and C.

F.B and D.

Answer 1

Ans: Correct option is A

Promoter sequence of a particular gene is where all transcription Factor bind and assemble to recruit RNA POLYMERASE at correct position and in correct orientation to initiate transcription of a gene. Promoter can be long and short and ate find upstream to the gene.

Therefore, if, promoter of a gene is deleted then transcription factors will be unable to recruit RNA polymerase to its correct position and therefore, transcription will not occur and the corresponding pre mRNA will not be synthesised.

Other options are incorrect,

Because if transcription would not occur, then the possibility of longer and shorter transcript, pre-mRNA than normal will also not be synthesised. Absence of promoter, results in absence of transcription factors binding, this will disturb the overall assembly of initiation complex and no transcript will be found.