2. http://publications.nigms.nih.gov/thenewgenetics/chapter1.html

3. DNA Structure DNA consists of two molecules that are arranged into a ladder-like structure called a Double Helix. A molecule of DNA is made up of millions of tiny subunits called Nucleotides. Each nucleotide consists of: 1. Phosphate group 2. Pentose sugar 3. Nitrogenous base

4. http://i-biology.net/ahl/07-nucleic-acids-and-proteins/

5. Nucleotides Phosphate Pentose Sugar Nitrogenous Base

6. Nucleotides The phosphate and sugar form the backbone of the DNA molecule, whereas the bases form the “rungs”. There are four types of nitrogenous bases.

7. Analogies Strengths of Ladder Analogy Weaknesses of Ladder Analogy double-helix shape is well represented location of sugar- phosphate backbone is accurate location of nucleotides is accurate individual nucleotides (A, T, C, G) are not represented individual sugars and phosphates are not shown base pairing (A-T, C-G) is not represented

8. Nucleotides A Adenine T Thymine G Guanine C Cytosine

9. Nucleotides Each base will only bond with one other specific base. Adenine (A) Thymine (T) Cytosine (C) Guanine (G) Form a base pair.

10. DNA Structure Because of this complementary base pairing, the order of the bases in one strand determines the order of the bases in the other strand. http://1.bp.blogspot.com/_gWQaU40PH24/S7J- tYkvibI/AAAAAAAAGas/-_raVWK4zx4/s1600/dna%5B1%5D.gif

11. Complementary base pairing PurinesPyramidines Adenine Thymine AdenineUracil GuanineCytosine

12. G G A T T A A C T G C A T C

13. Hydrogen bonds hold bases together.

14. DNA Structure To crack the genetic code found in DNA we need to look at the sequence of bases. The bases are arranged in triplets called codons. A G G - C T C - A A G - T C C - T A G T C C - G A G - T T C - A G G - A T C

15. A gene is a section of DNA that codes for a protein. Each unique gene has a unique sequence of bases. This unique sequence of bases will code for the production of a unique protein. It is these proteins and combination of proteins that give us a unique phenotype.

16. Protein DNA Gene Trait

17. Nature of the Genetic Material Property 1 - it must contain, in a stable form, information encoding the organism’s structure, function, development and reproduction Property 2 - it must replicate accurately so progeny cells have the same genetic makeup Property 3 - it must be capable of some variation (mutation) to permit evolution

18. Your Task Draw a flow chart to show how to get from:

19. http://207.207.4.198/pub/flash/24/menu.swf Nova-Cracking the Code of Life The Structure of DNA