1. Warm Up 3 2/3 What does DNA replication mean?
When does DNA need to make a copy of itself?
What does “template” mean?

2. DNA Replication
When cells divide (mitosis), their DNA makes a copy during S phase of the cell cycle

3. DNA Replication
The “original” molecule has two complementary strands

4. DNA Replication separation of the two strands by helicase
forms 2 template strands

6. DNA Replication
Each strand has all the info to make other half because of base pairing
New nucleotide attach to original strand

7. DNA Replication Final Product:
2 DNA’s (each have 1 original and 1 new strand)

8. DNA polymerase: enzyme that joins nucleotides to make DNA & proofreads new strand
Section 12-2
Original strand
DNA polymerase
New strand
Growth
DNA polymerase
Growth
Replication fork
Replication fork
Nitrogenous bases
New strand
Original strand
After DNA Polymerase is done, other enzymes “proofread” and correct the new strand.
The error rate is about 1 error per 10,000,000,000 nucleotide.to Section:

9. The Race to Discover DNA’s Structure
X-Ray diffraction 1952
Rosalind Franklin

10. Watson & Crick 1953
Developed double helix model

11. Warm Up 2
1. Look at the difference between a prokaryote cell (left) and an eukaryote cell(right). How do you think the DNA might be different in the two? 11

12. 2. Nitrogen bases are held together by ___________ bonds.
3. What is cell division?
4. Put the following in order:
G1 phase, mitosis, G2 phase, S phase, cytokinesis 12

14. 12.2 DNA Length

15. Prokaryotes
5 million base pairs needs to fit into a space 1/1000 of its length

16. Eukaryotes 1000 times more DNA than prokaryotes
million base pairs per cell

17. proteins called histones which forms nucleosome (bead of histone+DNA).
DNA wraps around
proteins called histones which forms
nucleosome (bead of histone+DNA).
Coils to make chromatin.
Supercoils to form chromosome.
DNA
Double Helix
Nucleosomes
Chromosome
Coils
Supercoils
Histones

19. DNA
Double Helix
Nucleosomes
Chromosome
Coils
Supercoils
Histones