Repressor slows down transcription.
RNA Polymerase enzyme transcribes mRNA from DNA.
Explanation:
Promoters are the 100 to 900 bps long sequence of DNA, that helps in the initiation of transcription. The transcription gets slow down as repressor bind to the promoter region hampering the attachment of RNA Polymerase enzyme which is responsible for transcription.
The process of transcription is the conversion of DNA into mRNA as told in the central dogma of molecular biology. Enzyme responsible for transcription is RNA polymerase. It is the first phase of gene expression, where DNA strand is copied into mRNA called a primary transcript.
When you shower with hot water, everytime you get out the shower, outside it is cold, but inside it is hot due to the hot gas particles. When you shower with cold water, it is the opposite.