1. Chapter 2 Nucleic Acids Guest Lecture: Israel Lidsky

2. Quizzes What you need to know on quizzes is covered in lecture You will have one of today’s structures on the quiz

3. Aims Nucleic Acids: fine structure Nucleic Acids: Multiple cellular roles Genes: sequence matters

4. Learning Outcomes Draw a dinucleotide List functional properties of nucleic acids List properties of nucleic acids that make them suitable as carriers of hereditary information

5. Figure 02.09A: A step-wise method for drawing a deoxyribonucleotide. How to actually draw it Clues Keywords Ribose Ribonucleic Acid Deoxyribonucleic Acid Phosphate Group Ribose Nitrogenous Base Dehydration Negative Charge

6. Figure 02.09B: A step-wise method for drawing a deoxyribonucleotide. Keywords Nitrogenous Base Ring Structure Purines Pyrimidines Adenine Thymine Guanine Cytosine Hydrogen Bonds GC Content

7. Figure 02.09C: A step-wise method for drawing a deoxyribonucleotide. Keywords dNTP

8. Figure 02.10: Distinctinctive features of ribonucleotides. Keywords Ribonucleic Acid Uracil Mono- Di- Tri-

9. Figure 02.11: The general structure of a nucleic acid. Keywords Linear Polymer Elongation 5’ to 3’ Phosphate Backbone Pyrophosphates ~Hint Quiz Hint~

10. Sample Quiz Question Two ______ are released whenever DNA elongates by addition of a single ______ a)Nitrogenous bases : Phosphate Group b)Water Molecules : Nucleotide c)Phosphate Groups : Nucleotide d)SyFy Rip-Offs : Sci-Fi Blockbuster

11. Figure 02.12A: Level 1 of DNA organization is a double stranded, antiparallel double helix held together by hydrogen bonds between base pairs. Keywords DNA Double Helix Double Stranded Antiparallel 5’ to 3’ Right Hand Rule Hydrogen Bonds Base Pair

12. Figure 02.12B: A 3D drawing showing the spatial arrangement of the nucleotides in a DNA double helix.

13. RNA Single Stranded (except for SiRNA) Can carry information Messenger RNA (mRNA) Has Enzymatic, Structural, and Interfering properties Not limited to simple structures

14. Transfer RNA Anticodons which recognize codons Bound to amino acids Deliver amino acids to rRNA Graphic submitted to Wikipedia by Yikrazuul Yeast Phenylalanine tRNA

15. Ribosomal RNA (rRNA) Small SubunitLarge Subunit Thermus thermophilus (animated by David S. Goodsell) Two Subunits Contains proteins Site of protein synthesis

16. Figure 02.05: An overview of translation in eukaryotes. Animated

17. Central Dogma DNARNAProtein TranscriptionTranslation Replication

18. Figure 02.01: Some forms of information storage in cells. DNA has “cellular information” in nucleus Other forms of information are used by the cell RNA has intermediate roles towards protein synthesis in the cytosol

19. DNA and Genes DNA carries genetic information (not obvious) DNA is : – Linear – Polar – Reproducible (minimal error, nucleotides easily recognized) – Transcribes efficiently (dNTPs are small and plentiful) – Language with few letters and small words for all 20 amino acids – Mutable

20. Figure 02.04: The smallest function unit of DNA is a gene. Keywords DNA Gene Regulatory Sequence Coding Sequence Exon Intron RNA Splicing

21. Figure 02.03: DNA information is "read" by proteins. Keywords DNA Gene Regulatory Sequence Transcription factors Proteins

22. Figure 02.02: Mistakes in DNA replication may cause mutations.

23. Figure 02.06: Mutations can alter amino acid sequence and protein function.

24. Figure 02.07: A single point mutation causes sickle cell disease. Mutation in code brings change. Affects to survival: good bad benign Survival itself is context dependent

25. Figure 02.08: Mutations accumulate slowly in a population of cells. Wear Sunscreen

26. Learning Outcomes Draw a dinucleotide List functional properties of nucleic acids Information storage, regulatory control, information transfer & conversion, enzymatic, structural, interference List properties of nucleic acids that make them suitable as carriers of hereditary information Linear molecule, polarity, quickly transcribed, synthesizing four nucleotides is efficient, simple codons call for all amino acids and starts and stops, and mutable