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FINDING DNA

FINDING DNA. Proof of DNA as Genetic Material. Was the genetic material protein or DNA? Mendel (peas) and Morgan (flies) did not know it was DNA. Worksheet links Bozeman Biology: DNA and RNA Part I Bozeman Biology: DNA and RNA Part II. Frederick Griffith.

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FINDING DNA

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  1. FINDING DNA

  2. Proof of DNA as Genetic Material • Was the genetic material protein or DNA? • Mendel (peas) and Morgan (flies) did not know it was DNA. Worksheet links • Bozeman Biology: DNA and RNA Part I Bozeman Biology: DNA and RNA Part II

  3. Frederick Griffith • A medical officer was trying to find a vaccine against pneumococcus

  4. Rough and Smooth Pneumococcus

  5. Griffith 1920’s • Streptococcus pneumoniae used to show a “transforming factor”

  6. Griffith’s Conclusion • Some material in the heat-killed S strain that was responsible for “transforming” the R-strain into a lethal form • transformation= passing the inheritance factor from one organism to another • THIS TRANSFORMING FACTOR WAS LATER FOUND TO BE DNA

  7. Oswald Avery 1944 He had reported that DNA, not protein (which was believed at the time), was the hereditary substance (transforming material). Studied medical research

  8. Oswald Avery 1940’s

  9. Avery’s Conclusion • Removed DNA, RNA, protein from S-strain pneumococcus • AVERY PROVED THAT DNA WAS THE TRANSFORMING MATERIAL

  10. Alfred Hershey and Margaret Chase 1953 • Showed that the hereditary material in bacteriophage viruses is DNA. DNA in water

  11. Hershey-Chase

  12. Hershey-Chase Bacteriophages Youtube • McGraw-Hill Hershey-Chase Experiment Radioactive P32 in DNA Radioactive S35 in protein

  13. Hershey-Chase • CONCLUSION – • DNA is genetic material because (32P)nucleic acid not (35S)protein guides viral replication

  14. Bacteriophages (“bacteria-eaters”) Mostly made of just protein coat and DNA

  15. Virus Examples HIV Virus • Cold Virus Bird Flu Virus Ebola Virus

  16. Herpes Virus

  17. Bacteriophage Structure

  18. Virus: Are they Alive? • Viruses can only replicate in a living host. • "Viruses straddle the definition of life. They lie somewhere between supra molecular complexes and very simple biological entities. Viruses contain some of the structures and exhibit some of the activities that are common to organic life, but they are missing many of the others.” • Dr. Mark Young of MSU youtube (4:00)

  19. Bacteriophage Lytic Infection • Attach to host • 2. Insert DNA • 3. Make and assemble DNA parts • 4. Lyse (burst) EXAMPLES: Cold Flu

  20. Lysogenic Infection • BIOL 230 Lecture Guide - Lysogenic Life Cycle of a Temperate Bacteriophage (animation link) • 1. Virus lands on host. • 2. Virus injects DNA into host. • 3. Virus DNA attaches to host DNA = prophage. • 4. Virus Prophage will become lytic when conditions are favorable (you are sick, tired).

  21. Lysogenic Cycle Animation • Animation Quiz 2 - Lamda Phage Replication Cycle • EXAMPLES:HERPESHIV • CHICKEN POX

  22. Click on “Journey into DNA” • NOVA Online | Cracking the Code of Life | Journey into DNA (keep clicking on “zoom” + button) • View for extra credit • Write 10 things you learned about DNA

  23. What is the structure of DNA? • It is a nucleic acid • Polynucleotide = Made of long chains of Nucleotides

  24. Phosphate Group O O=P-O O 5 CH2 O N Nitrogenous base (A, G, C, or T) C1 C4 Sugar (deoxyribose) C3 C2 DNA Nucleotide

  25. NUCLEOTIDE POLYNUCLEOTIDE DNA Structure

  26. MADE OF: Sugar Phosphate Base Deoxyribose sugar PO4 4 kinds: (A) (G) (T) (C) (names on next slide) A Nucleotide

  27. 4 Types of Base Pairs • A = adenine • T = thymine • C = cytosine • G = guanine • NOW SING THE DNA SONG

  28. A or G T or C Nitrogenous Bases • PURINES -2 rings 1. Adenine (A) 2. Guanine (G) • PYRIMIDINES -1 ring 3. Thymine (T) 4. Cytosine (C)

  29. DNA • Deoxyribonucleic Acid • (Get out colored pencils)

  30. “Rungs of ladder” Nitrogenous Base (A,T,G or C) “Legs of ladder” Phosphate & Sugar Backbone DNA Double Helix

  31. DNA backbone • Sugar • Phosphate

  32. DNA Structure • Rungs of the Ladder: • Various orders of A, T, C, G • Backbone: • Sugar and phosphates • Alternate

  33. 5 O 3 3 O P P 5 5 C O G 1 3 2 4 4 2 1 3 5 O P P T A 3 5 O O 5 P P 3 DNA Double Helix

  34.  National DNA Day, April 25, 2009 • DNA SONG AND VIDEOhttp://www.terrificscience.org/general/dnavideo.jsp

  35. Ribonucleic Acid Three types: mRNA tRNA rRNA What’s RNA?

  36. DNA Double stranded Sugar = deoxyribose Bases: A-T, C-G Found only in nucleus Can repair itself RNA Single stranded Sugar = ribose Bases: A-U, C-G Found in and out of the nucleus Cannot repair itself Comparing DNA and RNA

  37. RNA DNA

  38. Uracil Thymine Pretty Similar

  39. DNA RNA Both • Single stranded molecule • Contains uracil • Contains ribose sugar • - Found in nucleus and cytoplasm • Made of nucleotides • - Contain adenine, guanine and cytosine • Contains Thymine • Contains deoxyribose sugar • Double stranded molecule • - Found only in nucleus

  40. Bozeman Biology DNA and RNA Part 1 • Griffith, Avery, Hershey and Chase, Watson and Crick, pro and eukaryotic chromos • Bozeman Biology DNA and RNA part 2 • DNA replication • Transformation • Protein synthesis

  41. Relative Proportions (%) of Bases in DNA Organisms A T G C • Human 30.9 29.4 19.9 19.8 • Chicken 28.8 29.2 20.5 21.5 • Grasshopper 29.3 29.3 20.5 20.7  • Sea Urchin 32.8 32.1 17.717.3 • Wheat 27.3 27.1 22.7 22.8 • Yeast 31.3 32.9 18.7 17.1 • E. coli 24.7 23.6 26.0 25.7

  42. Question: • If there is 30%Adenine, how much Cytosine is present? • HINT: A –T and C - G

  43. Answer: • There would be 20%Cytosine. Adenine (30%) = Thymine (30%) Guanine (20%) = Cytosine (20%) Total of 100%

  44. Chargaff’s Rules • the amount of (A)denine will always equal the amount of (T)hymine • And • the amount of (G)uanine will always equal the amount of (C)ytosine. HOT!!!

  45. Nitrogenous Bases • Why does A bond only with T and C only with G? • What do you notice?

  46. Nitrogenous Bases T and C are single-ring Pyrimidines A and G are double-ring Purines A single bonds with a double

  47. 2 chains of nucleotides bind to form a DNA molecule • Hydrogen bonds form between the nitrogenous bases to join the 2 chains together • The sugar and phosphate group together is known as the sugar-phosphate backbone

  48. ENZYMES FOR DNA REPLICATION • Helicase = separates 2 DNA strands (breaks H bonds) • Primase=RNA primers at INITIATION

  49. REPLICATION ENZYMES • Topoisomerase = unwinding DNA • DNA Polymerase = Adding of DNA nucleotides ELONGATION (proofread and repair)

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