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Nucleic Acids

Nucleic Acids. The nucleic acids DNA and RNA consist of monomers called nucleotides that consist of a Pentose sugar. Nitrogen-containing base. Phosphate. nucleotide. Nitrogen Bases. The nitrogen bases in DNA and RNA are Pyrimidines C, T, and U Purines A and G. Pentose Sugars.

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Nucleic Acids

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  1. Nucleic Acids The nucleic acids DNA and RNA consist of monomers called nucleotidesthat consist of a Pentose sugar. Nitrogen-containing base. Phosphate. nucleotide

  2. Nitrogen Bases The nitrogen bases in DNA and RNA are Pyrimidines C, T, and U Purines A and G.

  3. Pentose Sugars The pentose (five-carbon) sugar In RNA is ribose. • InDNA is deoxyribosewith no O atom on carbon 2’. • Has carbon atoms numbered with primes to distinguish them from the atoms in nitrogen bases.

  4. A nucleoside Has a nitrogen base linked by a glycosidic bond to C1’ of a sugar (ribose or deoxyribose). Is named by changing the the nitrogen base ending to -osine for purines and -idine for pyrimidines. Nucleosides HO

  5. A nucleotide Is a nucleoside that forms a phosphate ester with the C5’ –OH group of a sugar (ribose or deoxyribose). Nucleotides • Is named using the name of the nucleoside followed by 5’-monophosphate

  6. Nucleosides and Nucleotides with Purines

  7. Nucleosides and Nucleotides with Pyrimidines

  8. Primary Structure of Nucleic Acids

  9. Structure of RNA The primary structure of RNA Is a single strand of nucleotides. Consists of the bases A, C, G, and U linked by 3’-5’ ester bonds between ribose and phosphate.

  10. Structure of DNA In the primary structure of DNA, A, C, G, and T are linked by 3’-5’ ester bonds between deoxyribose and phosphate.

  11. Data of Erwin Chargaff Chargaff’s Rules: %A = %T; %G = %C

  12. X–Ray Diffraction Pattern of DNA Helical Cross

  13. DNA Secondary Structure Double Helix

  14. “It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.” Watson, J.D and F.H.C. Crick Nature 171, 737-738 (1953) DNA ReplicationWatson-Crick Idea

  15. DNA Replication

  16. DNA Replication

  17. Transcription: DNA to RNA

  18. Transcription of mRNA

  19. tRNA Structure

  20. Induction of genes normally repressed (Inducer)

  21. Negative Regulation(bound repressor + corepressor inhibits transcription)Repression of genes normally expressed corepressor

  22. Posttranscriptional Processingof mRNA

  23. Genetic Code

  24. Protein Synthesis Amino Acid Activation Transfer energized amino acid to its specific tRNA. Energize the amino acid. Costs equivalent to 2 ATP.

  25. Protein Synthesis Translation

  26. Protein Synthesis: Role of Polysomes

  27. Antibiotics: Inhibitors of Protein Synthesis Streptomycin: inhibits initiation and causes misreading of the genetic code Tetracyclines: inhibit binding of aa-tRNA Chloramphenicol: inhibits peptide bond formation Erthromycin: inhibits translocation

  28. Mutations

  29. Recombinant DNA

  30. 3’ 5’ 5’ 3’ Third Cycle Second Cycle First Cycle Polymerase Chain Reaction (PCR) heat to separate the two strands add primers, cool to 55oC heat to separate the two strands heat to separate the two strands add primers, cool to 55oC use DNA polymerase, to extend chains use DNA polymerase, to extend chains add primers, cool to 55oC use DNA polymerase, to extend chains

  31. DNA Fingerprinting

  32. Retrovirus Action

  33. Examples of protease inhibitors: saquinavir, indinavir, ritonavir AIDS Virus and Treatment Examples of non-nucleoside reverse transcriptase inhibitors: etravirine, efavirenz, nevirapine AZT (3’-azido-3’deoxythymidine) (nucleoside analog reverse transcriptase inhibitor)

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