1. Do Now:

2. http://www.youtube.com/watch?v=KCFgi7Bq2M8

3. Frederick Griffith (1928) -Gave mice the bacterium that causes pneumonia (2 strains) -Smooth strain killed the mice (DEADLY) -Rough strain did not kill the mice (HARMLESS) -Killed smooth strain with heat, did not kill the mice -Mixed the harmless strain and the heat-treated deadly strain -He found that the harmless rough strain of pneumonia, TRANSFORMED into a deadly form. - He discovered the TRANSFORMING principle, genetic material (DNA or Protein?)

4. Oswald Avery(1944) -Wanted to test if protein was the transforming factor -Treated Griffith’s mixture of heat-treated deadly strain and live harmless strain with protein-destroying enzymes. -The bacterial colonies grown from the mixture were still transformed -Then treated the mixture with DNA destroying enzymes. -The bacterial colonies failed to transform. -Determine that the transforming factor is DNA by testing Griffith’s experiment

5. Alfred Hershey and Martha Chase(1952) -Conducted experiments using viruses to be sure DNA was the transforming factor, not protein. -A virus is DNA wrapped in a protein. They reproduce by infecting a living cell with genetic materal. - A virus that infects bacteria is a bacteriophage. -Concluded that the phage’s DNA entered the bacterial cell during infection but the proteins did not.

6. Roseland Franklin and Maurice Wilkins (1950s -Developed X-ray crystallography. Provides clues into shapes and dimensions of complex milecules. -Basic shape of DNA is a helix.

7. Watson and Crick -Modeled DNA’s structure. -Using Franklin’s work, created a new model in which two strands of nucleotides wound about each other, forming a double helix

8. Chargaff’s rules state that in any species there is an equal number of A and T bases, and an equal number of G and C bases

9. Sugar–phosphate backbone 5’ end Nitrogenous bases Thymine (T) Adenine (A) Cytosine (C) Guanine (G) DNA nucleotide Sugar (deoxyribose) 3’ end Phosphate