1. Chapter 12 section 2 and 3

2. Key Questions What are the chemical components of DNA? What clues helped scientists solve the structure of DNA? What does the double-helix model tell us about DNA?

3. Deoxyribonucleic Acid Nucleotide 1.Deoxyribose (sugar) 2.Phosphate (P & O atoms) 3.Nitrogen base (1 of 4) Adenine (A) Thymine (T) Guanine (G) Cytosine (C)

4. Structure of DNA Chargaff Franklin and Wilkins X-ray Watson and Crick

5. Double Helix Spiral staircase (twisted ladder) 2 nucleotide chains S-P “backbone” Antiparallel Nitrogen Base “rungs” H bonds Base Pair Rule

6. Key Questions What role does DNA polymerase play in copying DNA? How does DNA replication differ in prokaryotic cells and eukaryotic cells?

7. DNA Replication S phase One strand of DNA becomes the pattern for another

8. The Process 1.DNA Helicase unwinds and unzips 2.DNA Polymerase attaches, proofreads 3.Releases

9. Telomeres End Prevents damage

10. Prokaryotes vs. Eukaryotes Single Starting Point Two Directions Many Starting Points Two Directions Prokaryotes Eukaryotes