DNA (Deoxyribonucleic Acid)

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

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)

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

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

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

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

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…

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

(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)