1. Information Today –Chapter 14 and 16 highlights Wed., 30 November –Final exam review – BRING YOUR QUESTIONS! –Instructor evaluations Mon., 12 December, 2:15-4:15pm in C317 –Final Exam kpeterson@oeb.harvard.edu Office: B-203 (by appointment)

2. Chapter 14 READ: – Key Concepts – 14.1 – 14.2

3. 1) DNA is transcribed to form RNA 2) RNA is translated to form polypeptide chains, which fold to form proteins DNA to Proteins

4. 3 Classes of RNAs Messenger RNA (mRNA) –Protein-building instruction Ribosomal RNA (rRNA) –Major component of ribosomes Transfer RNA (tRNA) –Delivers amino acids to ribosomes

5. Base Pairing during Transcription DNA RNAG C A T C G T A G C A U C G T A base pairing in DNA replicationbase pairing in transcription

6. Transcription Small DNA stretch = template RNA polymerase = enzyme Product = 1 RNA strand transcribed DNA winds up again DNA to be transcribed unwinds mRNA transcript RNA polymerase PROTEIN INSTRUCTIONS

7. Genetic Code 64 base triplets Triplets = codons –61 = amino acids –3 = stop Figure 14.7 Page 230

8. tRNA Structure codon in mRNA anticodon amino acid OH amino-acid attachment site Figure 14.8 Page 231 BRINGS AMINO ACIDS TO RIBOSOMES

9. Overview Transcription Translation mRNA rRNAtRNA Mature mRNA transcripts ribosomal subunits mature tRNA

10. Chapter 16 READ 16.2, 16.4

11. Polymerase Chain Reaction (PCR) Double-stranded DNA to copy DNA heated to 90°– 94°C Primers added to base-pair with ends Mixture cooled; base-pairing of primers and ends of DNA strands DNA polymerases assemble new DNA strands Figure 16.6 Page 256 Stepped Art

12. Polymerase Chain Reaction Figure 16.6 Page 256 Stepped Art Mixture heated again; makes all DNA fragments unwind Mixture cooled; base- pairing between primers and ends of single DNA strands DNA polymerase action again doubles number of identical DNA fragments

13. Gel Electrophoresis DNA placed at one end of a gel A current is applied DNA molecules (-) move to + end Small molecules faster than large

14. Nucleotides for Sequencing Standard nucleotides (A, T, C, G) Modified versions –Fluoresce –Stop DNA synthesis

15. Reactions Proceed PCR Stops with modified nucleotide Millions of copies of varying length

16. Recording the Sequence T C C A T G G A C C T C C A T G G A C T C C A T G G A T C C A T G G T C C A T G T C C A T T C C A T C C T C T electrophoresis gel one of the many fragments of DNA migrating through the gel one of the DNA fragments passing through a laser beam after moving through the gel T C C A T G G A C C A DNA placed on gel Fragments move by size Pass through laser beam Color of each fragment is recorded on printout Figure 16.8 Page 258

17. Information Today –Chapter 14 and 16 highlights Wed., 30 November –Final exam review – BRING YOUR QUESTIONS! –Instructor evaluations Mon., 12 December, 2:15-4:15pm in C317 –Final Exam kpeterson@oeb.harvard.edu Office: B-203 (by appointment)