1. DNA
The Molecule of Life

2. The Basics of DNA DNA = DeoxyriboNucleic Acid
Found in the Nucleus of cells
Made up of nucleotides containing 3 parts:
5 Carbon Sugar = Deoxyribose
Phosphate Group
Nitrogen Base

3. The Bases There are 4 different Nitrogen Bases for DNA
They are divided into 2 groups based on their chemical structure
Purines = Adenine & Guanine
Pyrimidines = Cytosine and Thymine

5. DNA Structure
We refer to the structure of DNA as a Double Helix (spiral)
It resembles a twisted ladder
Its sides are formed from long chains of sugar & phosphate
The ‘rungs’ are the pairs of Nitrogen bases

7. Just some interesting facts
All 46 chromosomes in humans contain more than 5 Billion nucleotides!
The smallest known virus contains about 5,000 nucleotides
The structural and chemical make-up of DNA is the same in all organisms!
Only the sequence of the nucleotides varies

8. How the structure forms…
A purine and a pyrimidine must pair with each other make a rung that is the right width
If 2 purines were together, it would be too wide
If 2 pyrimidines were together, it would not be wide enough
Weak Hydrogen bonds hold the bases together
They are able to break easily, allowing the DNA to open like a zipper

9. Replication
The process by which DNA copies itself is called replication
The H-bonds connecting the bases break in several places and the molecule separates down the middle
As the molecule splits into separate strands, special enzymes cause the proper nucleotides to pair with complementary nucleotides on each strand

10. Replication continued…
Other enzymes then link the nucleotides into one long strand
Each original strand serves as a template or pattern, for the creation of the new strand
Every T (Thymine) nucleotide pairs with a nucleotide containing an A (Adenine)
Every G (Guanine) nucleotide pairs with a nucleotide containing a C (Cytosine)

13. Final thoughts of Replication
Each completed DNA molecule now contains one old and one new strand
The entire process is powered by energy from ATP and the action of enzymes

15. Just a Preview….. Coming soon to a classroom near you!
RNA….the OTHER nucleic acid

16. Any Questions??
That’s all folks!