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What carries genetic information?

What carries genetic information?. Agenda for Tuesday May 3 rd Intro DNA notes Create DNA. Timeline of Identifying Genetic Material. Genetic Material Transforms Bacteria - Frederick Griffith, 1931 DNA is the hereditary material - Oswald Avery, Colin MacLeod, and Maclyn McCarty, 1944

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What carries genetic information?

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  1. What carries genetic information? Agenda for Tuesday May 3rd • Intro DNA notes • Create DNA

  2. Timeline of Identifying Genetic Material • Genetic Material Transforms Bacteria - Frederick Griffith, 1931 • DNA is the hereditary material - Oswald Avery, Colin MacLeod, and Maclyn McCarty, 1944 • The Genetic Material is DNA - Alfred D. Hershey and Martha Chase, 1952 • Erwin Chargaff, 1940’s and early 50's • M.H.F. Wilkins and Rosalind Franklin, early 50’s • James Watson and Francis H.C. Crick, 1953

  3. Discovery of DNA Griffith • 2 strains of bacteria • Smooth (pneumonia) • Rough (no pneumonia) • Conclusion • Disease was passed • One strain was transformed into the other

  4. Discovery of DNA Avery • Isolated macromolecules from killed S cells • DNA, protein, lipids • Found that living R cells exposed to S strain DNA turned into S cells • Conclusion • DNA released • R strain incorporated this DNA into its cells

  5. Discovery of DNA Hershey and Chase • Bacteriophages – virus that attacks bacteria • DNA and protein • Viruses must inject DNA into living cell • Labeled both parts of virus (DNA and protein) • Radioactive isotopes • DNA – labeled phosphorous • Proteins – labeled sulfur • Conclusion • DNA provided info needed to produce new viruses

  6. DNA - Deoxyribose nucleic acid • Store and transmit genetic information • Composed of smaller nucleotides • DNA is an ideal genetic material • store information • able to replicate • undergo changes (mutate)

  7. Structure of DNA Nucleotides – 3 parts • Deoxyribose sugar • Phosphate group • Nitrogenous base • A, T, C, G

  8. Nitrogenous Bases • 4 Bases • Adenine (A), Thymine (T), Cytosine (C), Guanine (G) • Purine – Double ring • A and G • Pyrimidine – single ring • T and C

  9. Chargaff’s Rule • Found amount of guanine equals amount of cytosine • Amount of adenine nearly equals thyamine • Chargaff’s rule: C=G A=T

  10. Discovering Structure of DNA X – Ray Diffraction • Maurice Wilkins and Rosalind Franklin • Photo 51 • Indicated DNA was a double helix • http://www.pbs.org/wgbh/nova/photo51/

  11. James Watson and Francis Crick Double Helix Model • Used Franklin’s Photo and Chargaff’s data Features of Model **Similar to ladder that is twisted** 1. Sides formed by sugar-phosphate backbone 2. rungs (or steps) formed by hydrogen bonding between bases of nucleotides 3. bases display complimentary base pairing -- purine always bond to a pyrimidine • A always bonds with T and G always bonds with C

  12. DNA is Complementary • Complementary: bases on one strand match up with the bases on the other strand • (A-T and G-C) Example: Strand 1- ATG GGC CTA Strand 2- TAC CCG GAT

  13. Orientation of DNA • The nucleotides form a chain • The phosphate end of the chain is referred to as the 5' end. The opposite end is the 3' end. • Q: Since DNA is complementary, what end matches with the 5’ end?

  14. Remember DNA is like an Oreo Phophates + sugars = cookies Bases = cream filling Final Thoughts:DNA • Similar to a ladder • Rails (outside of ladder) are deoxyribose and phosphate • Base pairs are rungs of ladder • Twisted

  15. Chromosome Structure • Prokaryotes – DNA is in the shape of a ring • Eukaryotic – chromosomes • 51 – 245 million base pairs • 5 centimeters • Coils tightly around histones and forms nucleosome • Nucleosome group together and form chromatin fibers • Chromatin fibers form chromosomes

  16. Chromosome Structure Chromatin Fibers • DNA wraps around histones • 8 histones combine to form nucleosome Histones Nucleosomes

  17. Remember!! • 2 strands allow bases to pair • A binds T with 2 H bonds • C binds G with 3 H bonds Phosphates + sugars on the outside Bases on the inside (Bases fit like puzzle pieces)

  18. Info on Bases • Purine – double ring base • Guanine, Adenine • Pyrimidine – single ring base • Cytosine, Thymine

  19. What is a nucleotide made of (3 parts)? Agenda for Wednesday May 4th • Create DNA

  20. What shape is DNA? How was this discovered? Agenda for Thursday May 5th • Finish Making DNA • DNA Extraction lab

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