1. DNA Structure and Replication REVIEW

2. Nucleic Acids
DNA and RNA
Polymers (long chains) of nucleotides

3. Nucleotide
Made of a Sugar = Deoxyribose (DNA) or Ribose (RNA) Phosphate group Nitrogenous Base (A,T,G or C…U in RNA)

4. Paired bases DNA structure Bases match together double helix
2 sides like a ladder
Bases match together
A pairs with T
A : T
C pairs with G
C : G
phosphate
sugar
N base

5. Nitrogenous bases Our alphabet has 26 letters
Can create many different words  many different sentences  billions of different books of information.
DNA’s alphabet has 4 letters
A, T, C, and G
Create 3 letter words  Amino acids  proteins  billions of different organisms

6. Copying DNA
Matching bases allows DNA to be easily copied

7. Making new DNA Copying DNA replication
DNA starts as a double-stranded molecule
matching bases (A:T, C:G)
then it unzips…

8. DNA replication Strands “unzip” at the weak bonds between bases
Enzyme: DNA helicase

9. DNA replication Enzyme DNA polymerase adds new bases
DNA bases in nucleus
Enzyme
DNA polymerase
adds new bases
DNA
polymerase

10. Copying DNA Build daughter DNA strand
use original parent strand as “template”
add new matching bases
synthesis enzyme = DNA polymerase
DNA
Polymerase

11. New copies of DNA
Get 2 exact copies of DNA to split between new cells. Semi-Conservative (1 old and 1 new strand)
DNA
polymerase
DNA
polymerase

12. Gaps are closed (zipped closed)
The nucleotides are connected to form the sugar-phosphate backbones of the new strands. DNA ligase
Each “daughter” DNA molecule consists of one parental strand and one new strand….semi-conservative

13. Reviewing DNA Replication
Replication #3 and more