So if we have many of these genes and many of these nucleotides how exactly does the RNA polymerase know where to bind and begin the process of transcription of some particular gene of interest? Well, basically in prokaryotic as well as eukaryotic cells we have these regions on the DNA known as promoter regions or promoter sites. And what these promoter sites are, there are specific sequences of nucleotides that can bind very well to the RNA polymerase. And so when the RNA polymerase binds onto the promoter side, it knows it has to begin the process of transcription. Now, even though both bacterial cells, which are prokaryotic cells and human cells which are eukaryotic cells contain these promotocides, they are slightly different. So let's begin by discussing the promotosides we would normally find in a prokaryotic cell such as a bacterial cell.