Chapter 12.1 molecular genetics

2,177 views

Published on

Published in: Technology, Education
  • Be the first to comment

Chapter 12.1 molecular genetics

  1. 1. Chapter 12 – Molecular Genetics
  2. 2. 12.1 DNA: The Genetic Material (Pgs. 326-332)
  3. 3. Frederick Griffith (1928) <ul><li>Studied 2 strains of the bacteria Streptococcus pneumoniae </li></ul><ul><li>Found that one strain could be transformed into the other form </li></ul>
  4. 4. Frederick Griffith Rough Smooth
  5. 5. Oswald Avery (1944) <ul><li>Took Griffith’s work and discovered that DNA was the “transforming molecule” </li></ul>
  6. 6. Hershey & Chase (1952) <ul><li>Provided evidence that DNA was the “transforming factor” </li></ul><ul><li>Used bacteriophage (virus that attacks bacteria) </li></ul><ul><li>Used radioactive labeling </li></ul><ul><li>Read pp. 327-328 </li></ul>
  7. 7. Bacteriophage <ul><li>Made of DNA and protein </li></ul><ul><li>Inject DNA into host cell </li></ul>
  8. 8. Hershey and Chase
  9. 9. DNA Structure <ul><li>DNA is a nucleic acid that stores and transmits genetic information. </li></ul><ul><li>Polymer made up of nucleotides </li></ul><ul><li>5-carbon sugar (deoxyribose), phosphate group, </li></ul><ul><li>nitrogen base </li></ul>
  10. 10. DNA Structure <ul><li>P.A. Levine determined basic structure of nucleotides </li></ul>
  11. 11. Base Groupings <ul><li>Purines (Double ringed) </li></ul><ul><li>Adenine (A) </li></ul><ul><li>Guanine (G) </li></ul><ul><li>Pyrimidines (Single ringed) </li></ul><ul><li>Cytosine (C) </li></ul><ul><li>Thymine (T) </li></ul>
  12. 12. <ul><ul><ul><li>Backbone of DNA chain formed by sugar and phosphate groups of nucleotides </li></ul></ul></ul>sugar phosphate
  13. 13. DNA
  14. 14. DNA Structure <ul><li>Nucleotides bond to form 2 long chains (weak hydrogen bonds) resulting in a ladder like structure called a double helix </li></ul><ul><li>DNA found in nucleus </li></ul>
  15. 16. Erwin Chargaff <ul><li>Discovered that base pairing is the force that holds the two strands of the DNA double-helix together </li></ul><ul><li>Chargaff’s Rule C=G and A=T </li></ul>
  16. 17. Rosalind Franklin & Maurice Wilkins <ul><li>Made x-ray diffraction photographs to study DNA structure </li></ul><ul><li>Photo 51 </li></ul>
  17. 18. James Watson & Francis Crick <ul><li>Credited with discovering double helix model of DNA (see figure 12.8, p. 331) </li></ul><ul><li>C-G pair by 3 hydrogen bonds </li></ul><ul><li>A-T pair by 2 hydrogen bonds </li></ul><ul><li>Hypothesized a method of replication </li></ul>
  18. 19. Watson and Crick

×