19. If mRNA is complementary to the DNA template strand and the DNA template strand is complementary to the DNA non-template strand, then why are base sequences of mRNA and the DNA non-template strand not identical? Could they ever be?
20. A scientist observes that a cell has an RNA polymerase deficiency that prevents it from making proteins. Describe three additional observations that would together support the conclusion that a defect in RNA polymerase I activity, and not problems with the other polymerases, causes the defect.
21. Describe how transcription in prokaryotic cells can be altered by external stimulation such as excess lactose in the environment
22. Describe how controlling gene expression will alter the overall protein levels in the cell.