1. DNA

2. What is DNA? DeoxyriboNucleic Acid Found in all cells of the body
Nucleic Acid – composed of nucleotides
Carries all genetic information used in development and instructions of living things
Chromosome: carries the genetic code from 1 cell to another during cell division

3. Structure of DNA Made of 5-carbon sugar (deoxyribose), a nitrogen
Double Helix
Discovered by Watson
and Crick
Composed of nucleotides
Made of 5-carbon sugar
(deoxyribose), a nitrogen
containing base attached to the sugar, and a phosphate group.

4. Who Discovered structure of DNA?
Watson and Crick
1953
“Double stranded helix”

5. purines and pyrmidines
DNA has 4 Nitrogen Bases
Adenine
Thymine
Guanine
Cytosine
purines and pyrmidines

6. Pairing the Bases A T C G Adenine pairs with Thymine
Held together by Hydrogen Bonds:
Easy to separate during replication, but strong to hold DNA structure
Adenine pairs with Thymine
Cytosine pairs with Guanine

7. DNA Replication During DNA replication, the DNA
molecule ‘unzip’ into two strands.
By enzyme HELICASE
DNA Repication takes place BEFORE
a cell divides, to make sure each
cell has a complete set of DNA

8. DNA Replication Continued….
Each strand that is unwound in the double helix DNA serves as a template, or model, for the new strand.
Each strand of DNA
has 1 old strand
and 1 new strand

9. DNA Replication Continued….
DNA then produces two NEW complimentary strands following the rules of base pairing by enzyme DNA POLYMERASE
C pairs with G
G pairs with C
T pairs with A
A pairs with T
**The sequence of nucleotides in DNA codes for proteins (central key to cell function and life**