Final answer:
The presence of the core promoter by itself typically results in low transcription levels, requiring additional elements like transcription factors for enhanced activity. Mutated promoters affect transcription by altering the binding sites for transcription factors, which can increase, decrease, or even stop transcription.
Step-by-step explanation:
The question addresses whether the presence of the core promoter by itself results in a low level of transcription. The core promoter is a crucial component in the process of transcription initiation. It comprises a sequence of nucleotides at the beginning of a gene and triggers the start of transcription. However, the core promoter alone often leads to a minimal level of transcriptional activity. It typically requires additional elements like transcription factors to enhance the efficiency and rate of transcription.
Mutations within the promoter region can significantly affect the rate of transcription. A mutated promoter might decrease the rate of transcription by altering the binding sites for transcription factors, making it more difficult for them to bind and thus effectively slowing down the transcription process. Conversely, a mutation could potentially increase the rate of transcription if it leads to a change that enhances the binding of RNA polymerase or transcription factors.
In extreme cases, mutated promoters could fundamentally change the binding site such that transcription factors cannot bind at all, which would cease transcription of the adjacent gene. Thus, mutations in promoter regions are significant because they can drastically alter gene transcription.