Terminology

1. Terminology • Genetics Study of what genes are, how they carry information, how information is expressed, and how genes are replicated • Gene Segment of DNA that encodes a functional product, usually a protein

2. Terminology • Genome All of the genetic material in a cell • Genomics Molecular study of genomes • Genotype Genes of an organism • Phenotype Expression of the genes

3. E. coli Figure 8.1a

4. Flow of Genetic Information Figure 8.2

5. DNA • Polymer of nucleotides: adenine, thymine, cytosine, guanine • Double helix associated with proteins • "Backbone" is deoxyribose-phosphate • Strands held together by hydrogen bonds between AT and CG • Strands are antiparallel Figure 8.4

6. DNA Figure 8.3

7. DNA Figure 8.5

8. DNA • DNA is copied by DNA polymerase • In the 5 3 direction • Initiated by an RNA primer • Leading strand synthesized continuously • Lagging strand synthesized discontinuously • Okazaki fragments • RNA primers are removed and Okazaki fragments joined by a DNA polymerase and DNA ligase

9. DNA Figure 8.6

10. DNA • DNA replication is semiconservative Figure 8.7

11. DNA Encodes Proteins • Transcription and Translation are the processes necessary to generate proteins.

12. T P CS Transcription Pol GENE • DNA is transcribed to make RNA (mRNA, tRNA, and rRNA) • Transcription proceeds in the 5 3 direction

13. Transcription Figure 8.8

14. Translation • mRNA is translated in codons (3 nucleotides) – 64 possibilities • Translation of mRNA begins at the start codon: AUG • Translation ends at a STOP codon: UAA, UAG, UGA • 3 types of RNA are used to generate proteins Figure 8.2

15. Translation Figure 8.9

16. Translation Figure 8.10.1

17. Translation Figure 8.10.2

18. Translation Figure 8.10.3

19. Translation Figure 8.10.4

20. Translation Figure 8.10.5

21. Translation Figure 8.10.6

22. Translation Figure 8.10.7

23. Translation Figure 8.10.8

24. Translation Figure 8.11

25. RNA processing in Eukaryotes Figure 8.12

26. Regulation of Bacterial Gene Expression • Constitutive enzymes are expressed at a fixed rate • Other enzymes are expressed only as needed • Repressible enzymes • Inducible enzymes

27. Repression Figure 8.13

28. Operon Enzymes involved in lactose metabolism - B-galactosidase -permease -transacetylase Figure 8.14.1

29. Regulation of Gene Expression Figure 8.14.2

30. Regulation of Gene Expression Figure 8.14.3

31. Regulation of Gene Expression Lactose Present in the media Figure 8.14.4

32. Regulation of Gene Expression Figure 8.14.5

33. Regulation of Gene Expression Figure 8.15