Final answer:
The false statement is option B: T7 RNAP recognizes 1000 phage promoters. T7 RNAP specifically recognizes a hairpin-shaped promoter in its own bacteriophage, enabled by a specificity loop, and does not bind to a large number of different phage promoters.
Step-by-step explanation:
The false statement among the provided options about T7 RNA polymerase (RNAP) is option B: T7 RNAP recognizes 1000 phage promoters. T7 RNAP is specific to its own promoter, which is a 19-nucleotide long sequence that folds into a hairpin structure, rather than recognizing a large number of phage promoters. This specificity is due to a specificity loop that aids in recognizing the promoter sequence, thus determining the initiation site for transcription. Additionally, T7 RNAP indeed has a DNA binding region and an active site, just like other polymerases, and is indeed a single peptide, which manages its function without the need for additional factors or subunits.
Further understanding of the promoter comes from the definition of a promoter, which is a specific sequence of DNA nucleotides where the transcription machinery binds to initiate transcription (not a sequence of RNA nucleotides, a protein, or an enzyme that synthesizes RNA). Furthermore, the -10 and -35 regions upstream of the initiation site help facilitate the unwinding of the DNA due to their A-T richness. T7 RNAP is an important tool used in in vitro transcription where it synthesizes RNA from a DNA template.