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

UNFIGURE 6.1.

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

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

FIGURE mRNA processing in eukaryotes.

FIGURE 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 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 The glucocorticoid hormone receptor acts to increase gene transcription in the presence of hormone.

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