1. DNA and RNA June.19.2010

2. Chemical structure of DNA

7. The chemical nature of RNA differs from that of DNA RNA is a polymer of purine and pyrimidine ribonucleotides linked together by 3’, 5’- phosphodiester Bridges analogous to those in DNA. Although sharing many features with DNA, RNA possesses several specific differences

9. DNA OH¯ OH¯ DNA RNA DNA RNA

14. Posttranscriptional modification of mRNA showing the 7-methylguanosine cap and poly-A tail.

16. Thymidine, pseudouridine, cytidine

17. A. Characteristic tRNA secondary structure. B. Folded (tertiary) tRNA structure found in cells. D = dihydro-uracil. ψ = pseudouracil.

18. Primary tRNA transcript. B. Functional tRNA after posttranscriptional modification. Modified bases include D (dihydrouracil), ψ ( pseudouracil), and m , which means that the base has been methylated.

19. AUG

20. Genetic Code

22. Posttranscriptional processing of eukaryotic ribosomal RNA by ribonucleases (RNases)

23. Prokaryotic and eukaryotic rRNAs

26. Structure of eukaryotic messenger RNA

27. Alternative splicing patterns in eukaryotic mRNA.

31. Differences between DNA and RNA DNA RNA 1. Sugar moiety is deoxyribose. Sugar moiety is ribose. 2. Uracil is absent. Thymine is absent. . 3. Double stranded molecules. Single stranded molecules. 4. Sum of purine bases is equal to sum of pyrimidine base. (A+G)=(C+T) Sum of purine bases is not equal to sum of pyrimidine base. (A+G)#(C+T) 5. Resistant to hydrolysis by alkali because of absence of hydroxyl group on 2 carbon atom of deoxyribose. Because of presence of hydroxyl group on 2 carbon atom of ribose, RNA is easily hydrolyzed by alkali.

33. 以上です。