1. DNA Replication pp

2. Covalent > Hydrogen
What is DNA made of?
__________
What type of bond holds a nucleotide together?
What type of bond holds the two strands of nucleotides together?
Covalent > Hydrogen
WHY?
MOVIE A

3. Replication Making copies of DNA
Occurs when a cell divides to make new cells
The two strands separate and unwind acting as a template to add new nucleotides
MOVIE B

5. First Step
DNA is split by an enzyme (helicase), breaking the hydrogen bonds
replication fork: point where it separates:

6. Second Step
DNA polymerase adds nucleotides to the open areas ( A-T, G-C) as it unzips
Nucleotides attach from surrounding area

7. Process continues until entire strand is copied
Result is two strands of DNA
Each strand is 50% new and 50% old DNA (semi-conservative)

8. Accuracy and Repair Copies must be 100% accurate
Mutation= change in nucleotide at one location
Enzymes proofread and fix errors