DNA Structure, Function, And Replication In Biology Practice Test

Initiation of transcription in eukaryotes requires assembling RNA polymerase II at the gene’s promoter with promoter-bound transcription factors. These factors recognize promoter elements and recruit RNA polymerase II to form the pre-initiation complex, properly orienting the enzyme to start RNA synthesis. Additional players like the Mediator complex and chromatin remodelers help make the promoter accessible and regulate the process, and TFIIH opens the DNA and phosphorylates the polymerase to start elongation. This coordinated assembly at the promoter explains why transcription begins only after promoter-bound transcription factors recruit RNA polymerase II, not by RNA polymerase II acting alone, not by ribosomes, and not by DNA polymerase. The other options describe processes that do not initiate transcription in this way.