1. Fig. 11-2 Muscle cell Pancreas cells Blood cells If all human cells have the same number of genes, how can we have some 300 different cell types?

2. Figure 11.1B_1 Operon turned off (lactose is absent): OPERON Regulatory gene Promoter Operator Lactose-utilization genes RNA polymerase cannot attach to the promoter Active repressor Protein mRNA DNA

3. Figure 11.1B_2 Protein mRNA DNA Operon turned on (lactose inactivates the repressor): RNA polymerase is bound to the promoter Lactose Inactive repressor Translation Enzymes for lactose utilization

4. Figure 11.1C Inactive repressor Active repressor Lactose Tryptophan DNA Promoter Operator Gene lac operon trp operon

5. Figure 11.7_1 Chromosome DNA unpacking Other changes to the DNA Gene DNA Transcription Gene Exon Intron Tail Cap Addition of a cap and tail RNA transcript Splicing mRNA in nucleus NUCLEUS Flow through nuclear envelope CYTOPLASM

6. Figure 11.7_2 mRNA in cytoplasm CYTOPLASM Breakdown of mRNA Translation Polypeptide Broken- down mRNA Cleavage, modification, activation Active protein Amino acids Breakdown of protein

7. Figure 11.2A DNA double helix (2-nm diameter) “Beads on a string” Linker Histones Supercoil (300-nm diameter) Nucleosome (10-nm diameter) Tight helical fiber (30-nm diameter) Metaphase chromosome 700 nm

8. Figure 11.3 Enhancers DNA Promoter Gene Transcription factors Activator proteins Other proteins RNA polymerase Bending of DNA Transcription

9. Figure 11.4 DNA RNA transcript mRNA Exons Introns Cap Tail RNA splicing or 1 1 1 1 2 2 22 4 4 4 5 5 55 3 3 3

10. Figure 11.5 miRNA Target mRNA mRNA degraded or Translation blocked miRNA- protein complex Protein 3214

11. Figure 11.6 Folding of the polypeptide and the formation of S—S linkages Initial polypeptide (inactive) Folded polypeptide (inactive) Active form of insulin Cleavage S S S S S S S S S S S S SH Protein folding and activation (post-translational modifications)

12. Figure 11.2B Cell division and random X chromosome inactivation Early Embryo Adult X chromo- somes Allele for orange fur Allele for black fur Two cell populations Active X Inactive X Active X Inactive X Black fur Orange fur Epigenetics and imprinting

13. Figure 11.10 3 2 1 4 5 6 Signaling cell EXTRACELLULAR FLUID Signaling molecule Receptor protein Plasma membrane Target cell Relay proteins Signal transduction pathway Transcription factor (activated) NUCLEUS DNA mRNA CYTOPLASM Transcription Translation New protein

14. Figure 11.18A Growth factor Target cell Normal product of ras gene Relay proteins Receptor Hyperactive relay protein (product of ras oncogene) issues signals on its own CYTOPLASM DNA NUCLEUS Transcription Translation Protein that stimulates cell division Transcription factor (activated)

15. Figure 11.18B Growth-inhibiting factor Receptor Relay proteins Transcription factor (activated) Nonfunctional transcription factor (product of faulty p53 tumor-suppressor gene) cannot trigger transcription Normal product of p53 gene Transcription Translation Protein that inhibits cell division Protein absent (cell division not inhibited)