1. DNA REPLICATION
Chapter 11, Section 1

2. DNA Review What is the building block of DNA?
Nucleotides (Sugar, Phosphate, Base)
What is the shape of DNA?
Double Helix
What holds together the two strands of DNA?
Hydrogen bonds
During what part of the Cell Cycle does DNA replicate (copy itself)?
Interphase
What pairs with G? A? Hydrogen Bonds?
Guanine & Cytosine (3), Adenine & Thymine (2)
Which are the Purines? Pyrimidines?
Purines A&G (2 rungs) Pyrimidines T&C (3 rungs)
What are the complimentary bases for the following sequence? AATCCGC
TTAGGCG

4. How DNA Replicates DNA has to be replicated before a cell divides
New cells at the end of Mitosis need identical strands of DNA

5. One strand of DNA gets used as a template (pattern) to make a new strand that matches up with it
Special enzymes are required for DNA replication

6. Steps of DNA Replication
1. Replication begins with the unwinding & separation of the DNA double helix by enzymes called helicases
The process is like unzipping a zipper

7. 2. New strands are formed by enzymes called DNA polymerase which adds complimentary nucleotides to the original strands
3. Leading Strand (continuous) vs. Lagging Strand (discontinuous)

8. Semi-conservative Replication
Each new strand compliments one of the original strands
2 identical DNA double helix strands are the result of DNA replication

10. Uneven formation of DNA
When DNA is replicating one strand forms continuously and the other strand forms in chunks with spaces that need to be filled in

11. DNA 5’ to 3’ Anti-parallel
In the double helix one strand is “right-side up,” the other strand is “up-side down”
If not, the nitrogen bases wouldn’t be able to bond together

12. 5’ and 3’ come from how the carbons in the 5-carbon sugar get numbered

13. 5’ end
3’ end

14. DNA polymerase can only add nucleotides to the 3’ end of a strand of DNA
That means that the newly forming strand is forming from 5’ to 3’
That means…
One strand gets to form continuously
The other strand gets formed in chunks called Okazaki fragments that need to be connected by the enzyme DNA Ligase

15. http://highered. mcgraw-hill. com/olcweb/cgi/pluginpop. cgi
Important Terms- semiconservative replication, anti-parallel, 5’ to 3’