1. TRANSCRIPTION TRANSLATION DNA mRNA Ribosome Polypeptide (a) Bacterial cell Nuclear envelope TRANSCRIPTION RNA PROCESSING Pre-mRNA DNA mRNA TRANSLATION Ribosome Polypeptide (b) Eukaryotic cell 1

2. DNA molecule Gene 1 Gene 2 Gene 3 DNA template strand TRANSCRIPTION TRANSLATION mRNA Protein Codon Amino acid 2

3. Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon) 3

4. (a) Tobacco plant expressing a firefly gene (b) Pig expressing a jellyfish gene 4

5. Polypeptide Ribosome Amino acids tRNA with amino acid attached tRNA Anticodon Trp Phe Gly Codons 3 5 mRNA 5

6. Amino end of polypeptide mRNA 5 3 E P site A site GTP GDP E P A E PA GTP Ribosome ready for next aminoacyl tRNA E P A 6

7. Release factor 3 5 Stop codon (UAG, UAA, or UGA) 5 3 2 Free polypeptide 2 GDP GTP 5 3 7

8. Wild-type hemoglobin DNA mRNA Mutant hemoglobin DNA mRNA 3 3 3 3 3 3 5 5 5 5 5 5 CCTT T T G G A A A A AA A GG U Normal hemoglobinSickle-cell hemoglobin Glu Val 8