1. Understanding DNA Deoxyribonucleic Acid Double Helix: Two strands twisted around each other like a winding staircase

2. Rosalind Franklin & Maurice Wilkins

3. James Watson & Francis Crick

4. examples: DNA and RNA sugar phosphate nitrogen base nucleotide store genetic information, help to make proteins

5. Nucleotides A. Sugar (deoxyribose) B. Phosphate Group C. Nitrogen Bases A B C

6. Erwin Chargaff AT CG

7. Rules for Base Pairing: A.Cytosine-Guanine (C-G) B. Adenine- Thymine (A-T) The nucleotides are held together by Hydrogen bonds

8. * stores genetic information What is the function of DNA?

9. C G A A T G Sugar Phosphate Nitrogen Bases

11. Fun Facts If you wrote down all of the bases in one cell, you would fill a stack of 1,000 phone books with A's, T's, G's and C's

12. Fun Facts If you unraveled all your chromosomes from all of your cells and laid out the DNA end to end, the strands would stretch from the Earth to the Moon about 6,000 times.

13. DNA Replication

14. DNA Replication Results in two identical DNA strands 1. DNA helicase separates or“unwinds” DNA strands. 2. DNA polymerases add nucleotides to each strand. 3. Two identical DNA strands are made. Each DNA molecule is composed of one new and one old strand.

15. Proofreaders DNA polymerases make sure the correct nucleotide is added.