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 linksBozeman Biology: DNA and RNA Part I Bozeman Biology: DNA and RNA Part II
3 Frederick GriffithA medical officer was trying to find a vaccine against pneumococcus
5 Griffith 1920’sStreptococcus 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 formtransformation = passing the inheritance factor from one organism to anotherTHIS TRANSFORMING FACTOR WAS LATER FOUND TO BE DNA
7 Oswald Avery 1944He had reported that DNA, not protein (which was believed at the time), was the hereditary substance (transforming material).Studied medical research
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 host2. Insert DNA3. Make and assemble DNA parts4. Lyse (burst)EXAMPLES:ColdFlu
20 Lysogenic InfectionBIOL 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).
37 DNA RNA Comparing DNA and RNA Double stranded Sugar = deoxyribose Bases: A-T, C-GFound only in nucleusCan repair itselfRNASingle strandedSugar = riboseBases: A-U, C-GFound in and out of the nucleusCannot repair itself
40 DNA RNA Both Single stranded molecule Contains uracil Contains ribose sugar- Found in nucleus and cytoplasmMade of nucleotides- Contain adenine, guanine and cytosineContains ThymineContains deoxyribose sugarDouble stranded molecule- Found only in nucleus
41 Bozeman Biology DNA and RNA Part 1 Griffith, Avery, Hershey and Chase, Watson and Crick, pro and eukaryotic chromosBozeman Biology DNA and RNA part 2DNA replicationTransformationProtein synthesis
42 Relative Proportions (%) of Bases in DNA Organisms A T G C HumanChickenGrasshopper Sea UrchinWheatYeastE. coli
43 Question: If there is 30% Adenine, how much Cytosine is present? HINT: A –T and C - G
44 Answer: There would be 20% Cytosine. Adenine (30%) = Thymine (30%) Guanine (20%) = Cytosine (20%)Total of 100%
45 Chargaff’s Rulesthe amount of (A)denine will always equal the amount of (T)hymineAndthe amount of (G)uanine will always equal the amount of (C)ytosine.HOT!!!
46 Nitrogenous Bases Why does A bond only with T and C only with G? What do you notice?
47 Nitrogenous Bases T and C are single-ring Pyrimidines A and G are double-ringPurinesA single bonds with adouble
48 2 chains of nucleotides bind to form a DNA molecule Hydrogen bonds form between the nitrogenous bases to join the 2 chains togetherThe sugar and phosphate group together is known as the sugar-phosphate backbone
49 ENZYMES FOR DNA REPLICATION Helicase = separates 2 DNA strands (breaks H bonds)Primase=RNA primers at INITIATION
50 Topoisomerase = unwinding DNA REPLICATION ENZYMESTopoisomerase = unwinding DNADNA Polymerase = Adding of DNA nucleotides ELONGATION (proofread and repair)
51 DNA REPLICATION ENZYMES LIGASE= Binds the Okazaki fragmentsWatch the enzymes in DNA Replication Animation
52 AT and C-G Base Pairing DNA Replication simple version) (link) Media Showcase (cool animation link)Detailed Replication Link
54 in tons of combinations makes our genetic code DNA STRUCTUREA-TC-Gin tons of combinations makes our genetic code
55 DNA Replication Animation click here Hi!...Still Awake?DNA Replication Animation click here
56 What is the complementary base sequence on the other strand of the DNA? A T T G C C C T A AT A A C G G G A T T
57 The Race is On!To Determine the Structure of the DNA molecule.
58 DNA GeekRosalind Franklin was an English chemist who was working in an X-ray crystallography lab in Paris, France in 1951.FAMOUS PHOTO 51(correct orientation of DNA)
59 Linus Pauling American biochemist suggested helix (spiral)shape Most famous for Vitamin C prevents colds
60 DNA GeekLinus Pauling was a Caltech chemist (USA), who in 1951 had discovered the alpha helical nature of protein structure.I remember his books: Vitamin C and the Common Cold and Cancer and Vitamin C alsoThe Nature of the Chemical Bond and protested nuclear testing
61 DNA GeeksJames Watson, a biologist from Indiana University, and Francis Crick, a physicist, were working at the Cavendish Lab in Cambridge, England Nobel Prize for structure of DNA