1. DNA (Deoxyribonucleic Acid)

2. Genetic material of cells…DNA
GENES – units of genetic material that CODES FOR A SPECIFIC TRAIT
DNA is made up of repeating molecules called NUCLEOTIDES
A, T, C, G

3. A HISTORY OF DNA Discovery of the DNA double helix
A. Frederick Griffith – Discovers that a factor in diseased bacteria can transform harmless bacteria into deadly bacteria (1928)
B. Rosalind Franklin - X-ray photo of DNA.
(1952)
C. Watson and Crick - described the DNA molecule from Franklin’s X-ray.
(1953)

4. DNA pairings… DNA pairs in a very specific way: ADENINE – THYMINE
CYTOSINE - GUANINE
DNA was made of 2 long stands.

5. DNA Double Helix “Rungs of ladder” Nitrogenous Base (A,T,G or C)
“Legs of ladder”
Phosphate &
Sugar Backbone

6. DNA Pairing Rule… Adenine must pair with Thymine
Guanine must pair with Cytosine G C T A

7. Genetic Diversity… Asexual Reproduction Sexual Reproduction
(1 parent cell)
Sexual Reproduction
( 2 parent cells

8. The Code of Life…Sequence!
The “code” of the chromosome is the SPECIFIC ORDER that bases occur.
A T C G T A T G C G G…

9. DNA Replication during Mitosis
DNA must be copied
The DNA molecule produces 2 IDENTICAL new complementary strands following the rules of base pairing:
A-T, G-C
Each strand of the original DNA serves as a template for the new strand

10. (a library of about 1,000 books)
AMAZING DNA FACTS…
DNA from a single human cell extends in a single thread for almost 2 meters long!!!
It contains information equal to some 600,000 printed pages of 500 words each!!!
(a library of about 1,000 books)