FIGURE 6.1. RNA contains the sugar ribose and the base uracil in place of deoxyribose and thymine.

FIGURE 6.2. Synthesis of an RNA strand.

FIGURE 6.3. Numbering on a DNA sequence.

FIGURE 6.4. (A) RNA polymerase binds to the promoter to form the closed promoter complex. (B) The open promoter complex: The DNA helix unwinds and RNA polymerase synthesizes an RNA molecule.

FIGURE 6.5. Rho-independent trancription termination in Escherichia coli.

FIGURE 6.6. A bacterial operon is transcribed into a polycistronic mRNA.

FIGURE 6.7. Reactions catalyzed by -galactosidase.

FIGURE 6.8. Transcription of the lac operon requires the presence of an inducer.

FIGURE 6.9. Cyclic adenosine monophosphate, also called cyclic AMP or just cAMP.

FIGURE 6.10. For efficient transcription of the lac operon, both cAMP and a-galactoside sugar must be present.

UNFIGURE 6.1.

FIGURE 6.11. Isopropylthio- -D-galactoside (IPTG), which can bind to the lac repressor protein but which is not metabolized.

FIGURE 6.12. Transcription of the trp operon is controlled by the concentrationof the amino acid tryptophan.

FIGURE 6.13. mRNA processing in eukaryotes.

FIGURE 6.14. In eukaryotes, RNA polymerase II is guided to the promoter by TFII accessory proteins. (A) TBP binds to the TATA box. (B) The complete transcription preinitiation complex. (C) Phosphorylated RNA polymerase is active.

FIGURE 6.15. Tissue-specific transcription. The myosin IIa gene is not transcribed in liver cells, which do not contain the transcription factors Myo D and NFAT.

FIGURE 6.16. The glucocorticoid hormone receptor acts to increase genetranscription in the presence of hormone.

FIGURE 6.17. The dimerized glucocorticoid hormone receptor binds to a palindromic HRE.