1. Genes Determine the characteristics of individuals.
Found in the nucleus of the cell
Located on chromosomes
Aka DNA

2. Structure of DNA DNA is made of two long chains of nucleotides.
Each chain of nucleotides is formed by the sugar of one nucleotide connecting to the phosphate group of another nucleotide. P S N P S N

3. The bases from one chain complement the bases on the other chain
(Complement = they fit together like a lock and key.)
Adenine (A) complements Thymine (T)
Cytosine (C) complements Guanine (G) A T C G

4. Double strand showing complements

5. Because of the configuration of the nucleotides the DNA is in the form of a double helix.
A helix is shaped like a spring

6. DNA Replication
The DNA molecule unzips in both directions at many points

7. 1. Helicases unwind the parental (original)
double helix

8. DNA polymerase puts together free-floating nucleotides (that are complements to the old strand) to form a new strand

9. DNA polymerase also “proofreads” the new strand and corrects any mistakes

10. Okazaki Fragments Write this line from left to right
Write this line from right to left
Which way went more smoothly?

11. On the other strand Okazaki fragments are made
Primase makes an RNA primer which is replaced by DNA polymerase
DNA ligase joins the Okazaki fragments together