1. Review: The flow of genetic information in the cell is DNA  RNA  protein  The sequence of codons in DNA spells out the primary structure of a polypeptide  Polypeptides form proteins that cells and organisms use  Animation of Translation Animation of Translation

3. TRANSLATION

4. Figure 10.7 DNA molecule Gene 1 Gene 2 Gene 3 DNA strand TRANSCRIPTION RNA Polypeptide TRANSLATION Codon Amino acid

5. Transfer RNA molecules serve as interpreters during translation  In the cytoplasm, a ribosome attaches to the mRNA and translates its message into a polypeptide  The process is aided by transfer RNAs Figure 10.11A Hydrogen bond Amino acid attachment site RNA polynucleotide chain Anticodon

6.  Each tRNA molecule has a triplet anticodon on one end and an amino acid attachment site on the other Figure 10.11B, C Anticodon Amino acid attachment site

7.  An exercise in translating the genetic code Start codon RNA Transcribed strand Stop codon Translation Transcription DNA

8. Ribosomes build polypeptides Figure 10.12A-C Codons tRNA molecules mRNA Growing polypeptide Large subunit Small subunit mRNA mRNA binding site Growing polypeptide tRNA Next amino acid to be added to polypeptide

9. Table 14.2 Types of RNA Type of RNA Functions inFunction Messenger RNA (mRNA) Nucleus, migrates to ribosomes in cytoplasm Carries DNA sequence information to ribosomes Transfer RNA (tRNA) Cytoplasm Provides linkage between mRNA and amino acids; transfers amino acids to ribosomes Ribosomal RNA (rRNA) Cytoplasm Structural component of ribosomes

10. (continued) 4 Stage Elongation Growing polypeptide Codons 5 Stage Termination mRNA New peptide bond forming Stop Codon The ribosome recognizes a stop codon. The poly- peptide is terminated and released. A succession of tRNAs add their amino acids to the polypeptide chain as the mRNA is moved through the ribosome, one codon at a time. Polypeptide