DNA History,Structure,and

1. DNAHistory,Structure,and

2. Check out Griffith’s experiment on page 138 • What is up? • Shows how harmless bacteria can turn deadly. • How? DNA is transferred!

3. DNA(de-oxy-ribo-nucleic acid)a nucleic acid that stores and transmits the genetic information from one generation to the next

4. Big Players in DNA • Chargaff • Rosalind Franklin • Watson and Crick

5. People knew that DNA was made up of: • Adenine (A) • Guanine (G) • Cytosine (C) • Thymine (T)

6. Erwin Chargaff • Discovered that in any sample of DNA, the amount of A equals the amount of T and the amount of C equals the amount of G. • This suggested that A binds with T and that C binds with G.

7. Rosalind Franklin’sX-Ray Crystallography • Took x-ray photographs of crystallized DNA • Discovered that the shape of DNA must be a helix, because of the x-ray pattern • Died of cancer (too many x-rays?)

8. An example of X-Ray Crystallography

9. Watson and Crick • Credited for discovering the structure of DNA in 1953 • Used Chargaff and Franklin’s discoveries along with toy models to discover the structure

10. A 3-D Model of DNA

13. NUCLEOTIDES Made up of: • A phosphate group • 5 carbon sugar • Nitrogenous Base (nitrogen containing)

14. PURINES • Adenine (A) • Guanine (G)

15. PYRIMIDINES • Cytosine (C) • Thymine (T)

16. Base Pairing in DNA A-T C-G

19. Guanine Nucleotide

20. Write the complementary DNA strand for each of these DNA strands: • DNA • GAATTACA • CCAATTAG • ATAGACAG • CCAGTACA • DNA • CTTAATGT • GGTTAATC • TATCTGTC • GGTCATGT

21. Examples of DNA Replication