1. DNA History & Structure
AP Biology
DNA History & Structure

2. Nucleic Acid Structure

3. Complimentary Base Pairing

4. Frederick Griffith

5. Frederick Griffith Experiment
Mixture of heat-killed
S cells and living
R cells
Living S cells
(control)
Living R cells
(control)
Heat-killed
S cells (control)
RESULTS
Mouse dies
Mouse healthy
Mouse healthy
Mouse dies
Living S cells
are found in
blood sample

6. Oswald Avery

7. Alfred Hershey & Martha Chase

8. Bacteriaphage injecting it’s DNA into a bacterial cell

9. Electron Microscope View

10. Hershey – Chase Experiment

11. Erwin Chargaff

12. Adenine = Thymine (DNA) or Uracil (RNA)
Chargaff’s Rule
Adenine = Thymine (DNA) or Uracil (RNA)
&
Guanine = Cytosine
If you know the % composition of 1, you can find the % composition of the other 3.

13. Rosalind Franklin

14. DNA from a top view

15. DNA from a side view

16. James Watson & Francis Crick with their DNA model

17. See the HYDROGEN bonds?