1. Chapter Twenty Two Nucleic Acids

2. Copyright © Houghton Mifflin Company. All rights reserved.22 | 2 →CO 22.1 Human egg and sperm. Lipids cont’d Dr. Nikos / James Burns / Phototake

3. Copyright © Houghton Mifflin Company. All rights reserved.22 | 3 →Fig. 22.1 Molecule of Adenine, a nitrogen-containing heterocyclic base present in both RNA and DNA. Lipids cont’d

4. Copyright © Houghton Mifflin Company. All rights reserved.22 | 4 ←Fig. 22.2 Two purine bases and three pyrimidine bases are found in the nucleotides present in nucleic acids. Lipids cont’d

5. Copyright © Houghton Mifflin Company. All rights reserved.22 | 5 Table 22.1 Lipids cont’d

6. Copyright © Houghton Mifflin Company. All rights reserved.22 | 6 CAG 22.1 Lipids cont’d

7. Copyright © Houghton Mifflin Company. All rights reserved.22 | 7 Fig. 22.3 The general structure of a nucleic acid in terms of nucleotide subunits. Lipids cont’d

8. Copyright © Houghton Mifflin Company. All rights reserved.22 | 8 ←Fig. 22.4 (a) The generalized structure of a nucleic acid. (b) The specific backbone structure for a deoxyribonucleic acid (DNA). (c) The specific backbone structure for a ribonucleic acid (RNA). Lipids cont’d

9. Copyright © Houghton Mifflin Company. All rights reserved.22 | 9 →Fig. 22.5 A four-nucleotide-long segment of DNA. Lipids cont’d

10. Copyright © Houghton Mifflin Company. All rights reserved.22 | 10 Fig. 22.6 A comparison of the primary structures of nucleic acids and proteins. Lipids cont’d

11. Copyright © Houghton Mifflin Company. All rights reserved.22 | 11 →Fig. 22.7 A schematic drawing of the DNA double helix that emphasizes the hydrogen bonding between bases on the two chains. Lipids cont’d

12. Copyright © Houghton Mifflin Company. All rights reserved.22 | 12 ←Fig. 22.8 Hydrogen bonding possibilities Lipids cont’d

13. Copyright © Houghton Mifflin Company. All rights reserved.22 | 13 Fig. 22.9 DNA replication Lipids cont’d

14. Copyright © Houghton Mifflin Company. All rights reserved.22 | 14 Fig. 22.10 One strand of DNA grows continuously in the direction of the unwinding, and the other grows in the opposite direction. Lipids cont’d

15. Copyright © Houghton Mifflin Company. All rights reserved.22 | 15 →Fig. 22.11 DNA replication usually occurs at multiple sites within a molecule, and the replication is bidirectional from these sites. Lipids cont’d

16. Copyright © Houghton Mifflin Company. All rights reserved.22 | 16 ←Fig. 22.12 Identical twins share identical physical characteristics because they received identical DNA from their parents. Lipids cont’d © Erica Stone / Peter Arnold, Inc.

17. Copyright © Houghton Mifflin Company. All rights reserved.22 | 17 Lipids cont’d  CAG 22.2

18. Copyright © Houghton Mifflin Company. All rights reserved.22 | 18 Fig. 22.13 A hairpin loop is produced when a single-stranded RNA doubles back on itself and complementary base pairing occurs. Lipids cont’d

19. Copyright © Houghton Mifflin Company. All rights reserved.22 | 19 Fig. 22.14 An overview of types of RNA. Lipids cont’d

20. Copyright © Houghton Mifflin Company. All rights reserved.22 | 20 →Fig. 22.15 The transcription of DNA to form RNA involves an unwinding of a portion of the DNA double helix. Lipids cont’d

21. Copyright © Houghton Mifflin Company. All rights reserved.22 | 21 Fig. 22.16 Heterogenous nuclear RNA contains both exons and introns. Lipids cont’d

22. Copyright © Houghton Mifflin Company. All rights reserved.22 | 22 Fig. 22.17 An hnRNA molecule containing four exons. Lipids cont’d

23. Copyright © Houghton Mifflin Company. All rights reserved.22 | 23  Table 22.2 Lipids cont’d

24. Copyright © Houghton Mifflin Company. All rights reserved.22 | 24 ←Fig. 22.18 A tRNA molecule Lipids cont’d

25. Copyright © Houghton Mifflin Company. All rights reserved.22 | 25 →Fig. 22.19 An aminoacyl-tRNA synthetase has an active site for tRNA and a binding site for the particular amino acid that is to be attached to that tRNA. Lipids cont’d

26. Copyright © Houghton Mifflin Company. All rights reserved.22 | 26 ←Fig. 22.20 The interaction between anticodon an codon. Lipids cont’d

27. Copyright © Houghton Mifflin Company. All rights reserved.22 | 27 →Fig. 22.21 Ribosomes have structures that contain two subunits. Lipids cont’d

28. Copyright © Houghton Mifflin Company. All rights reserved.22 | 28 Fig. 22.22 Initiation of protein synthesis begins with the formation of an initiation complex. Lipids cont’d

29. Copyright © Houghton Mifflin Company. All rights reserved.22 | 29 →Fig. 22.23 The process of translation that occurs during protein synthesis. Lipids cont’d

30. Copyright © Houghton Mifflin Company. All rights reserved.22 | 30 CC 22.1 Lipids cont’d

31. Copyright © Houghton Mifflin Company. All rights reserved.22 | 31 ←Fig. 22.24 Several ribosomes can simultaneously proceed along a single strand of mRNA. Such a complex of mRNA and ribosomes is called a polysome. Lipids cont’d

32. Copyright © Houghton Mifflin Company. All rights reserved.22 | 32 Lipids cont’d  CAG 22.3

33. Copyright © Houghton Mifflin Company. All rights reserved.22 | 33 →Fig. 22.25 Image of an influenza virus. Lipids cont’d NIBSC / SPL / Photo Researchers

34. Copyright © Houghton Mifflin Company. All rights reserved.22 | 34 ←Fig. 22.26 Recombinant DNA is made by inserting a gene obtained from DNA of one organism into the DNA from another kind of organism. Lipids cont’d

35. Copyright © Houghton Mifflin Company. All rights reserved.22 | 35 →Fig. 22.27 Cleavage patterns resulting from the use of a restriction enzyme that cleaves DNA between G and A bases. Lipids cont’d

36. Copyright © Houghton Mifflin Company. All rights reserved.22 | 36 ←Fig. 22.28 The “sticky ends” of the cut plasmid and the gene are complementary and combine to form recombinant DNA. Lipids cont’d

37. Copyright © Houghton Mifflin Company. All rights reserved.22 | 37 →Fig. 22.29 The basic steps of the polymerase chain reaction process. Lipids cont’d

38. Copyright © Houghton Mifflin Company. All rights reserved.22 | 38 ←Fig. 22.30 Selected steps in the DNA sequencing procedure for the 10- base DNA segment 5’ AGCAGCTGGT 3’. Lipids cont’d